Effect of an Inactivated Vaccine Against SARS-CoV-2 on Safety and Immunogenicity Outcomes: Interim Analysis of 2 Randomized Clinical Trials

Myocarditis: causes, mechanisms, and evolving therapies

INTRODUCTION

Myocarditis is a severe lymphocyte-mediated inflammatory disorder of the heart, mostly caused by viruses and immune checkpoint inhibitors (ICIs). Recently, myocarditis as a rare adverse event of mRNA vaccines for SARS-CoV-2 has caused global attention. The clinical consequences of myocarditis can be very severe, but specific treatment options are lacking or not yet clinically proven.

AREAS COVERED

This paper offers a brief overview of the biology of viruses that frequently cause myocarditis, focusing on mechanisms important for viral entry and replication following host infection. Current and new potential therapeutic targets/strategies especially for viral myocarditis are reviewed systematically. In particular, the immune system in myocarditis is dissected with respect to infective viral and non-infective, ICI-induced myocarditis.

EXPERT OPINION

Vaccination is an excellent emerging preventative strategy for viral myocarditis, but most vaccines still require further development. Anti-viral treatments that inhibit viral replication need to be considered following viral infection in host myocardium, as lower viral load reduces inflammation severity. Understanding how the immune system continues to damage the heart even after viral clearance will define novel therapeutic targets/strategies. We propose that viral myocarditis can be best treated using a combination of antiviral agents and immunotherapies that control cytotoxic T cell activity.

Impaired Humoral Immunity Identified in Inactivated SARS-CoV-2 Vaccine Recipients without Anti-Spike RBD Antibodies

Inactivated SARS-CoV-2 vaccines have been deployed in a significant portion of the world population, who have widely varied responses to vaccination. Understanding this differential response would help the development of new vaccines for non-responders. Here, we conducted surveillance of anti-Spike receptor-binding domain (RBD) antibody levels in a large cohort of 534 healthy Chinese subjects vaccinated with two doses of inactivated SARS-CoV-2 vaccines. We show that the positive rate of antibodies among vaccinated subjects rapidly wanes as the interval between antibody testing and vaccination increases (14 to 119 days: 81.03%, 363 of 448 subjects; 120 to 149 days: 46.43%, 13 of 28 subjects; more than 150 days: 20%, 1 of 5 subjects). However, the antibodies were maintained at high levels in 16 convalescent COVID-19 patients at more than 150 days after recovery. We also found that increased age and body mass index are associated with decreased antibody levels. Vaccinated subjects who fail to produce antibodies display impaired B-cell activating humoral immunity, which was confirmed in COVID-19 patients without antibodies detected at 4 to 18 days after diagnosis. IMPORTANCE Our study illustrates the immune responses engaged by encountering antigen, highlighting the critical roles of B-cell activating humoral immunity in the body's antibody production.

Indirect Dispersion of SARS-CoV-2 Live-Attenuated Vaccine and Its Contribution to Herd Immunity

It has been 34 months since the beginning of the SARS-CoV-2 coronavirus pandemic, which causes the COVID-19 disease. In several countries, immunization has reached a proportion near what is required to reach herd immunity. Nevertheless, infections and re-infections have been observed even in vaccinated persons. That is because protection conferred by vaccines is not entirely effective against new virus variants. It is unknown how often booster vaccines will be necessary to maintain a good level of protective immunity. Furthermore, many individuals refuse vaccination, and in developing countries, a large proportion of the population has not yet been vaccinated. Some live-attenuated vaccines against SARS-CoV-2 are being developed. Here, we analyze the indirect dispersion of a live-attenuated virus from vaccinated individuals to their contacts and the contribution that this phenomenon could have to reaching Herd Immunity.

Side Effects of COVID-19 Vaccines Among Diabetic Subjects and Healthy Individuals

Objectives Vaccinations protect against disease through various ways, but the process of developing immunity might result in side effects. This study determined the immediate side effects of coronavirus disease 2019 (COVID-19) vaccination among patients with diabetes and non-diabetic participants. Methods This multi-center, cross-sectional study was conducted in multiple hospitals in Karachi, Pakistan. The duration of the study was six months, from March 1, 2022, to August 31, 2022. A total of 1150 participants who received one of the COVID-19 vaccines, for instance, Sinopharm, AstraZeneca, Sinovac, and Pfizer (double or booster doses) were included in the study and allocated into two groups: diabetics (n=540) and non-diabetics (n=610). The chi-square test was used to compare the frequency of side effects between diabetic and non-diabetic participants. The association between means of demographic variables such as age and weight was compared using an independent t-test. Results The study findings showed that the mean age of the group with diabetes was 46.73±14.98 years and that of the non-diabetic group was 44.01±14.80 years with a significant difference between them (p=0.002). The majority of participants, 187 (34.6%) patients with diabetes received Pfizer, while 234 (38.4%) non-diabetic participants received Sinovac. Following the first dose, side effects were higher in patients with diabetes. Burning at the injection site, fever, and pain were the most commonly reported side effects in patients with diabetes following the first dose. Additionally, following the second dose, burning at the injection site, muscular pain, fever, and pain were the most commonly observed side effects, with a significant association among diabetic and non-diabetic participants (p<0.001). Conclusion Diabetes is a prevalent comorbidity in individuals infected with COVID-19, and patients with diabetes report more side effects from immunization than non-diabetic participants. The most commonly reported side effects of the vaccine in diabetic participants were observed to be burning at the injection site, fever, muscle and joint pain, and swelling at the injection site. Additionally, participants with and without diabetes reported feeling satisfied with their vaccines.

An update on SARS-CoV-2 immunization and future directions

Millions of people have died as a result of SARS-CoV-2, which was first discovered in China and has since spread globally. Patients with SARS-CoV-2 infection may show a range of symptoms, including fever, coughing, and shortness of breath, or they may show no symptoms at all. To treat COVID-19 symptoms and avoid serious infections, many medications and vaccinations have been employed. However, to entirely eradicate COVID-19 from the world, next-generation vaccine research is required because of the devastating consequences it is having for humanity and every nation's economy. Scientists are working hard to eradicate this dangerous virus across the world. SARS-CoV-2 has also undergone significant mutation, leading to distinct viral types such as the alpha, beta, gamma, delta, and omicron variants. This has sparked discussion about the effectiveness of current vaccines for the newly formed variants. A proper comparison of these vaccinations is required to compare their efficacy as the number of people immunized against SARS-CoV-2 globally increases. Population-level statistics evaluating the capacity of these vaccines to reduce infection are therefore being developed. In this paper, we analyze the many vaccines on the market in terms of their production process, price, dosage needed, and efficacy. This article also discusses the challenges of achieving herd immunity, the likelihood of reinfection, and the importance of convalescent plasma therapy in reducing infection.

Antibody dependent disease enhancement (ADE) after COVID-19 vaccination and beta glucans as a safer strategy in management

A potential risk associated with vaccines for COVID-19 is antibody-dependent disease enhancement (ADE) in which vaccine induced antibody mediated immune responses may lead to enhanced SARS CoV- 2 acquisition or increased disease severity. Though ADE has not been clinically demonstrated with any of the COVID-19 vaccines so far, when neutralizing antibodies are suboptimal, the severity of COVID-19 has been reported to greater. ADE is presumed to occur via abnormal macrophages induced by the vaccine based immune response by antibody-mediated virus uptake into Fc gamma receptor IIa (FcγRIIa) or by the formation of Fc-mediated excessive antibody effector functions. Beta-glucans which are naturally occurring polysaccharides known for unique immunomodulation by capability to interact with macrophages, eliciting a specific beneficial immune-response and enhancing all arms of the immune system, importantly without over-activation are suggested as safer nutritional supplement-based vaccine adjuvants for COVID-19.

Effectiveness of BBIBP-CorV vaccine in preventing SARS-CoV2 infection and severe outcomes in people living with multiple sclerosis: A population-based study

BACKGROUND

The objective of the present study was to estimate the effectiveness of the BBIBP-CorV vaccine (VE) in preventing SARS-CoV-2 infection, related hospitalization, and death among people living with multiple sclerosis (PLWMS).

METHODS

In this population-based retrospective observational study, data on all PLWMS, vaccination, SARS-CoV-2 tests, hospitalization, and deaths were collected in Isfahan, Iran between February 9, 2021, and November 4, 2021. We estimated the hazard ratio between vaccinated (partially and fully) and unvaccinated groups using the Andersen-Gill extension of the Cox proportional hazards model. We also performed Cox proportional hazards analysis to identify risk factors for breakthrough infection and COVID-19-related hospitalization in fully-immunized group.

RESULTS

Of the 9869 PLWMS, 1368 were in partially-vaccinated group, 4107 were in the fully-vaccinated group, and 3794 were in the unvaccinated group. In the partially-vaccinated group, the estimated VE against COVID-19 infection was 39.3% (16%, 56.1%), hospitalization was 64.9% (1.3%, 87.5%), and mortality was 92.7% (88.8%, 100%). The respective results for the fully-vaccinated group were 63.9% (56%, 70.3%), 75.7% (57.5%, 86.1%), and 100%. Progressive MS was independently associated with a greater risk of breakthrough infection (HR=1.952, 95%CI: 1.174-3.246, p = 0.010). Older adults (≥50 years vs. 18-49 years, HR=3.115, 95%CI: 1.145-8.470, p = 0.026) and those on rituximab (HR=7.584; 95% CI: 1.864-30.854; p = 0.005) were at an increased risk of COVID-19-related hospitalization.

CONCLUSION

This study showed that two doses of the BBIBP-CorV vaccine can effectively prevent COVID-19 infection and hospitalization among PLWMS. Old PLWMS and those who treating with rituximab are at increased risk of hospitalization after receiving two doses of the vaccine.

Assessment of acceptance, concerns and side effects towards COVID-19 vaccination among the community: A cross-sectional study from Baghdad, Iraq

Introduction

The newly developed and marketed vaccines along with concerns about vaccine safety and long-term side effects has been raised an alarming in the general population. The aim of this study was to assess the rate of acceptance, perceptions and concerns towards receiving COVID-19 vaccines and to explore the incidence of vaccines' side effects among Iraqi population in Baghdad province, Iraq.

Method

This was a descriptive, cross-sectional study conducted via direct interviews among a convenient sample size of Iraqi population using a structured validated questionnaire consisting of using 24-item questionnaire to assess acceptance, concerns and the incidence of vaccines' side effects towards receiving COVID-19 vaccines.

Results

A total of 500 participants with an average age of 27.8 ± 3.7 years were included. Majority were females (70.6%). 43.4% had a history of COVID-19, and 46% received the Pfizer BioNTech vaccine. 73.4% (P < 0.0001) agreed about the importance of receiving the vaccination to protect the community against the COVID-19.46.8% (P < 0.0001) were unsure about the adverse effects and long-term vaccine safety. 72.8% reported that transmission of COVID-19 infection to family members is the main concern for accepting vaccination. Fatigue (60%), injection site reactions (55.8%) were the most common vaccine's side effects. Young age (P = 0.001), females (P < 0.0001), and university educational (P < 0.0001) were the most significant determents for accepting vaccination.

Conclusion

This study highlights that the Iraqi population showed a considerable acceptance rate for the COVID-19 vaccines. However, vaccine safety is considered a high priority concern associated with the willingness of the population to vaccinate.

An update on COVID-19: SARS-CoV-2 variants, antiviral drugs, and vaccines

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious and pathogenic virus that first appeared in late December 2019. This SARS-CoV-2 causes an infection of an acute respiratory disease called "coronavirus infectious disease-2019 (COVID-19). The World Health Organization (WHO) declared this SARS-CoV-2 outbreak a great pandemic on March 11, 2020. As of January 31, 2023, SARS-CoV-2 recorded more than 67 million cases and over 6 million deaths. Recently, novel mutated variants of SARS-CoV are also creating a serious health concern worldwide, and the future novel variant is still mysterious. As infection cases of SARS-CoV-2 are increasing daily, scientists are trying to combat the disease using numerous antiviral drugs and vaccines against SARS-CoV-2. To our knowledge, this is the first comprehensive review that summarized the dynamic nature of SARS-CoV-2 transmission, SARS-CoV-2 variants (a variant of concern and variant of interest), antiviral drugs and vaccines utilized against SARS-CoV-2 at a glance. Hopefully, this review will enable the researcher to gain knowledge on SARS-CoV-2 variants and vaccines, which will also pave the way to identify efficient novel vaccines against forthcoming SARS-CoV-2 strains.

Phase II randomized, double blind, placebo controlled, clinical trial of safety and immunogenicity of an inactivated SARS-CoV-2 vaccine FAKHRAVAC in adults aged 18-70 years

BACKGROUND

The FAKHRAVAC®, an inactivated SARS-CoV-2 vaccine, was assessed for safety and immunogenicity in a phase II trial.

METHODS

We did a phase II, single-centered, randomized, double-blind, placebo-controlled clinical trial of the FAKHRAVAC inactivated SARS-CoV-2 vaccine on adults aged 18 to 70. The two parallel groups received two intramuscular injections of either a 10-µg vaccine or a placebo at 2-week intervals. The participants' immunogenicity responses and the occurrence of solicited and unsolicited adverse events were compared over the study period of up to 6 months. Immunogenicity outcomes include serum neutralizing antibody activity and specific IgG antibody levels.

RESULTS

Five hundred eligible participants were randomly (1:1) assigned to vaccine or placebo groups. The median age of the participants was 36 years, and 75% were male. The most frequent local adverse reaction was tenderness (21.29% after the first dose and 8.52% after the second dose), and the most frequent systemic adverse reaction was headache (11.24% after the first dose and 8.94% after the second dose). Neutralizing antibody titers two and four weeks after the second injection in the vaccine group showed about 3 and 6 times increase compared to the placebo group (GMR = 2.69, 95% CI 2.32-3.12, N:309) and (GMR = 5.51, 95% CI 3.94-8.35, N:285). A four-fold increase in the neutralizing antibody titer was seen in 69.6% and 73.4% of the participants in the vaccine group two and four weeks after the second dose, respectively. Specific ELIZA antibody response against a combination of S1 and RBD antigens 4 weeks after the second injection increased more than three times in the vaccine compared to the placebo group (GMR = 3.34, 95% CI 2.5-4.47, N:142).

CONCLUSIONS

FAKHRAVAC® is safe and induces a significant humoral immune response to the SARS-CoV-2 virus at 10-µg antigen dose in adults aged 18-70. A phase III trial is needed to assess the clinical efficacy.

TRIAL REGISTRATION

Trial Registry Number: Ref., IRCT20210206050259N2 ( http://irct.ir ; registered on 08/06/2021).

SARS-CoV-2 Variant-Specific mRNA Vaccine: Pros and Cons

Emerging severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants have raised concerns about the efficacy of vaccines. The present study aimed to compare the potential of Delta and Omicron variant-specific mRNA vaccines in inducing immune responses. B cell and T cell epitopes and population coverage of spike (S) glycoprotein of the variants were predicted using the Immune Epitope Database. The molecular docking was carried out between the protein and different toll-like receptors, as well as the receptor-binding domain (RBD) protein and angiotensin-converting-enzyme 2 (ACE2) cellular receptor using ClusPro. The molecular simulation was done for each docked RBD-ACE2 using YASARA. The mRNA secondary structure was predicted through the RNAfold. The simulation of immune responses to the mRNA vaccine construct was performed using C-ImmSim. Apart from a few positions, no significant difference was observed in the prediction of S protein B cell and T cell epitopes of these two variants. The lower amounts of Median consensus percentile in the Delta variant in similar positions signify its stronger affinity to major histocompatibility complex (MHC) II binding alleles. Docking of Delta S protein with TLR3, TLR4, and TLR7 and also its RBD with ACE2 showed striking interactions with the lower binding energy than Omicron. In the immune simulation, elevated levels of cytotoxic T lymphocytes, helper T lymphocytes, and memory cells in both the active and resting states and the main regulators of the immune system suggested the capacity of mRNA constructs to elicit robust immune responses against SARS-CoV-2 variants. Considering slight differences in the binding affinity to MHC II binding alleles, activation of TLRs, mRNA secondary structure stability, and concentration of immunoglobulins and cytokines, the Delta variant is suggested for the mRNA vaccine construction. Further studies are being done to prove the efficiency of the design construct.

Immunological Findings in a Group of Individuals Who Were Poor or Non-Responders to Standard Two-Dose SARS-CoV-2 Vaccines

Coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared a pandemic. However, data on the poor or non-responders to SARS-CoV-2 vaccines in the general population are limited. The objective of this study was to comprehensively compare the immunological characteristics of poor or non-responders to SARS-CoV-2 vaccines in the 18-59-year group with those in the ≥60-year group using internationally recognized cut-off values. The main outcome was effective seroconversion characterized by an anti-SARS-CoV-2 spike IgG level of at least a four-fold increase from baseline. Profiling of naïve immune cells was analyzed prior to vaccination to demonstrate baseline immunity. The outcomes of effective seroconversion in patients aged 18-59 years with those in patients aged ≥60 years were compared. The quantitative level of anti-spike IgG was significantly lower in individuals aged ≥60 and men aged 18-59 years. There were 7.5% of poor or non-responders among the 18-59 years and 11.7% of poor or non-responders in the ≥60 years using a four-fold increase parameter. There were 37.0-58.1% with low lymphocyte count (<1000/mm³), 33.3-45.2% with low CD4 cell counts (<500/mm³), and 74.1-96.8% with low B cell counts (<100/mm³) in the non-seroconversion group. An individual with an anti-SARS-CoV-2 spike IgG titer below 50 BAU/mL might be considered a poor or non-responder between 14 and 90 days after the last vaccine dose. Booster vaccination or additional protective measures should be recommended to poor or non-responders as soon as possible to reduce disease severity and mortality.

Structural and Immunoreactivity Properties of the SARS-CoV-2 Spike Protein upon the Development of an Inactivated Vaccine

Inactivated vaccines are promising tools for tackling the COVID-19 pandemic. We applied several protocols for SARS-CoV-2 inactivation (by β-propiolactone, formaldehyde, and UV radiation) and examined the morphology of viral spikes, protein composition of the preparations, and their immunoreactivity in ELISA using two panels of sera collected from convalescents and people vaccinated by Sputnik V. Transmission electron microscopy (TEM) allowed us to distinguish wider flail-like spikes (supposedly the S-protein's pre-fusion conformation) from narrower needle-like ones (the post-fusion state). While the flails were present in all preparations studied, the needles were highly abundant in the β-propiolactone-inactivated samples only. Structural proteins S, N, and M of SARS-CoV-2 were detected via mass spectrometry. Formaldehyde and UV-inactivated samples demonstrated the highest affinity/immunoreactivity against the convalescent sera, while β-propiolactone (1:2000, 36 h) and UV-inactivated ones were more active against the sera of people vaccinated with Sputnik V. A higher concentration of β-propiolactone (1:1000, 2 h) led to a loss of antigenic affinity for both serum panels. Thus, although we did not analyze native SARS-CoV-2 for biosafety reasons, our comparative approach helped to exclude some destructive inactivation conditions and select suitable variants for future animal research. We believe that TEM is a valuable tool for inactivated COVID-19 vaccine quality control during the downstream manufacturing process.

COVID-19 therapy and vaccination: a clinical narrative review

The SARS-CoV-2 pandemic is the most globally impacting health issue our world has faced over the last century. As of January 7, 2022, around 300 million cases have been reported worldwide, with over 5 million deaths. The SARS-CoV-2 infection causes a hyperactive host immune response leading to an excessive inflammatory reaction with the release of many cytokines - cytokine storm - commonly noticed in acute respiratory distress syndrome, sepsis and fulminant multiorgan failure. Since the beginning of the pandemic, the scientific medical community has worked on therapeutic procedures that interfere with the exaggerated immune response. Thromboembolic complications are widespread in patients who are critically ill with COVID-19. Anticoagulant therapy was initially considered a cornerstone in hospitalized patients and even in the early post-discharge period; however, later trials have aborted the clinical benefits except for suspicion of or confirmed thrombosis. Immunomodulatory therapies are still crucial in moderate to severe COVID-19. Immunomodulator therapies include various medications from steroids to hydroxychloroquine, tocilizumab and Anakinra. Anti-inflammatory agents, vitamin supplements and antimicrobial therapy had initial encouraging evidence, but there are limited data to review. Convalescent plasma, immunoglobulins, eculizumab, neutralizing IgG1 monoclonal antibodies and remdesivir have positively impacted inpatient mortality and hospital length of stay. Eventually, wide population vaccination was proven to be the best tool to overcome the SARS-CoV-2 pandemic and help humanity return to regular life. Many vaccines and various strategies have been used since December 2020. This review discusses how the SARS-CoV-2 pandemic has progressed and surged, and summarizes the safety and efficacy of the most used therapies and vaccines in the light of recent evidence.

From Immunogen to COVID-19 vaccines: Prospects for the post-pandemic era

The COVID-19 pandemic has affected millions of people and posed an unprecedented burden on healthcare systems and economies worldwide since the outbreak of the COVID-19. A considerable number of nations have investigated COVID-19 and proposed a series of prevention and treatment strategies thus far. The pandemic prevention strategies implemented in China have suggested that the spread of COVID-19 can be effectively reduced by restricting large-scale gathering, developing community-scale nucleic acid testing, and conducting epidemiological investigations, whereas sporadic cases have always been identified in numerous places. Currently, there is still no decisive therapy for COVID-19 or related complications. The development of COVID-19 vaccines has raised the hope for mitigating this pandemic based on the intercross immunity induced by COVID-19. Thus far, several types of COVID-19 vaccines have been developed and released to into financial markets. From the perspective of vaccine use in globe, COVID-19 vaccines are beneficial to mitigate the pandemic, whereas the relative adverse events have been reported progressively. This is a review about the development, challenges and prospects of COVID-19 vaccines, and it can provide more insights into all aspects of the vaccines.

Safety of inactivated COVID-19 vaccines in autoimmune encephalitis: A real-world cross-sectional survey

OBJECTIVE

To assess safety data of the inactivated COVID-19 vaccines in a real-world sample of people with autoimmune encephalitis (pwAE).

METHODS

A cross-sectional study was performed between 1 March and 30 April 2022. We invited pwAE from our previous ONE-WC (Outcome of Autoimmune Encephalitis Study in Western China) registration study database, to attend neurological clinics, at West China Hospital to participate in a face-to-face survey using a custom-designed questionnaire for this study. The ONE-WC study began in October 2011 and prospectively enrolled pwAE from four large comprehensive neurological centers in Sichuan province, China.

RESULTS

Of the 387 pwAE, 240 (62.0%) completed the questionnaire. Half the 240 participants (121, 50.4%) reported receiving at least one dose of COVID-19 vaccine, which in all but two patients received inactivated COVID-19 vaccine. Among vaccinated pwAE, the median age was 35 years (range 15-69) and 57.8% of them were women. The most frequent reasons that unvaccinated individuals reported for not receiving the COVID-19 vaccine were concern about vaccine-induced relapse of AE (50.4%) and advice from a physician to delay vaccination (21.0%). Small proportions of vaccinated individuals reported adverse events after the first dose (11.5%) or the second dose (10.2%), and none of the adverse events was serious. Across the entire sample, one individual reported relapsing within 30 days after the first dose and three individuals reported relapsing more than 120 days after the first dose.

CONCLUSIONS

This real-world survey indicates an overall favorable safety profile of the inactivated COVID-19 vaccine for pwAE.

Long COVID: An inevitable sequela of SARS-CoV-2 infection

At present, there are more than 560 million confirmed cases of the coronavirus disease 2019 (COVID-19) worldwide. Although more than 98% of patients with severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection can survive acute COVID, a significant portion of survivors can develop residual health problems, which is termed as long COVID. Although severe COVID-19 is generally associated with a high risk of long COVID, patients with asymptomatic or mild disease can also show long COVID. The definition of long COVID is inconsistent and its clinical manifestations are protean. In addition to general symptoms, such as fatigue, long COVID can affect many organ systems, including the respiratory, neurological, psychosocial, cardiovascular, gastrointestinal, and metabolic systems. Moreover, patients with long COVID may experience exercise intolerance and impaired daily function and quality of life. Long COVID may be caused by SARS-CoV-2 direct injury or its associated immune/inflammatory response. Assessment of patients with long COVID requires comprehensive evaluation, including history taking, physical examination, laboratory tests, radiography, and functional tests. However, there is no known effective treatment for long COVID. Based on the limited evidence, vaccines may help to prevent the development of long COVID. As long COVID is a new clinical entity that is constantly evolving, there are still many unknowns, and further investigation is warranted to enhance our understanding of this disease.

Application of Traditional Vaccine Development Strategies to SARS-CoV-2

Over the past 150 years, vaccines have revolutionized the relationship between people and disease. During the COVID-19 pandemic, technologies such as mRNA vaccines have received attention due to their novelty and successes. However, more traditional vaccine development platforms have also yielded important tools in the worldwide fight against the SARS-CoV-2 virus. A variety of approaches have been used to develop COVID-19 vaccines that are now authorized for use in countries around the world. In this review, we highlight strategies that focus on the viral capsid and outwards, rather than on the nucleic acids inside. These approaches fall into two broad categories: whole-virus vaccines and subunit vaccines. Whole-virus vaccines use the virus itself, either in an inactivated or attenuated state. Subunit vaccines contain instead an isolated, immunogenic component of the virus. Here, we highlight vaccine candidates that apply these approaches against SARS-CoV-2 in different ways. In a companion manuscript, we review the more recent and novel development of nucleic-acid based vaccine technologies. We further consider the role that these COVID-19 vaccine development programs have played in prophylaxis at the global scale. Well-established vaccine technologies have proved especially important to making vaccines accessible in low- and middle-income countries. Vaccine development programs that use established platforms have been undertaken in a much wider range of countries than those using nucleic-acid-based technologies, which have been led by wealthy Western countries. Therefore, these vaccine platforms, though less novel from a biotechnological standpoint, have proven to be extremely important to the management of SARS-CoV-2.

Humoral immune response to inactivated COVID-19 vaccination at the 3rd month among people living with HIV

BACKGROUND

Research on the immune response to inactivated COVID-19 vaccination among people living with HIV (PLWH) is limited, especially among those with low CD4+ T lymphocyte (CD4 cell) count. This prospective cohort study aimed to assess the humoral immune response to inactivated COVID-19 vaccination among PLWH compared to HIV negative controls (HNCs) and to determine the impact of CD4 cell count on vaccine response among PLWH.

METHODS

The neutralizing antibodies (nAbs) and the specific IgM and IgG-binding antibody responses to the inactivated COVID-19 vaccine at the third month after the second dose of inactivated COVID-19 vaccination were measured among 138 PLWH and 35 HNCs. Multivariable logistic regression and multiple linear regression models were conducted to identify factors associated with the seroconversion rate of antibodies and the magnitude of anti-SARS-CoV-2 antibody titers, respectively.

RESULTS

At the end of the third month after two doses of vaccination, the seroconversion rates of IgG were comparable between PLWH (44.9%; 95% CI 36.5-53.3%) and HNCs (60.0%; 95% CI 42.9-77.1%), respectively. The median titers and seroconversion rate of nAbs among PLWH were 0.57 (IQR: 0.30-1.11) log10 BAU/mL and 29.0% (95% CI 21.3-36.8%), respectively, both lower than those in HNCs (P < 0.05). After adjusting for age, sex, comorbidities, and CD4 cell count, the titers and seroconversion rate of nAbs were comparable between PLWH and HNCs (P > 0.05). Multivariable regression analyses showed that CD4 cell count < 200/μL was independently associated with lower titers and seroconversion rate of nAbs among PLWH (P < 0.05). A positive correlation was observed between the CD4 cell count and nAbs titers in PLWH (Spearman's ρ = 0.25, P = 0.0034).

CONCLUSION

Our study concluded that the immune response to inactivated COVID-19 vaccination among PLWH was independently associated with CD4 cell count, PLWH with lower CD4 cell count showed a weaker humoral immune response, especially those with CD4 cell count < 200/μL. This finding suggests that expanding COVID-19 vaccination coverage among PLWH is impendency. In addition, aggressive ART should be carried out for PLWH, especially for those with low CD4 cell count, to improve the immune response to vaccines.

Evaluation of Short-Term Side Effects Following the First Dose of COVID-19 Vaccines Among Physicians and Dentists: A Cross-Sectional Study from India

BACKGROUND

Efficacy and safety are fundamental for the development of successful COVID-19 vaccines. Vaccine-associated side effects influence vaccine hesitancy. This study investigated the prevalence, severity, and onset of side effects following the first dose of COVID-19 vaccines among physicians and dentists working in various healthcare settings across India.

METHODS

A cross-sectional survey collected self-report data from April to June 2021 on side effects following the first dose of the vaccine. An online validated questionnaire using the Google Docs® platform was circulated via email and social media platforms.

RESULTS

More than 40% of participants experienced at least one side effect after the first dose of vaccination; the most common were mild and resolved within three days after vaccination. More than 91% of respondents received the Covishield (AstraZeneca) vaccine; the most prevalent adverse effects were soreness of the injected arm (78.9%), tiredness (71.1%), and fever (54.9%). Logistic regression showed that women were almost 60% less likely to report side effects.

CONCLUSION

Findings supported the safety of the first dose of the COVID-19 vaccine based on relatively few self-limiting side effects, mainly soreness of the injected arm and tiredness. Further research is needed to determine the long-term safety of COVID-19 vaccines, especially after booster doses.

Assessing the long-stand antibody response induced by COVID-19 vaccines: A study in an educational cohort in San Luis, Argentina

BACKGROUND

Although there has developed an increased interest in the vaccines BNT1622b2 (Pfizer/BioNTech), mRNA-1273 (Moderna/NIAID), and ChAdOx1 nCoV-19 (AstraZeneca/University of Oxford), there are still few reports describing the immune response induced by different vaccine platforms in real-world settings of low-income countries. Here, we proposed to analyse the humoral immune response elicited by the primary vaccines used in Argentina from July-December 2021.

METHODS

Anti-SARS-CoV-2-Spike-RBD IgG and neutralising antibodies were assayed by ELISA in a total of 871 serum samples obtained from 376 volunteers from an educational staff. The individuals were vaccinated with BBIBP-CorV (Sinopharm), ChAdOx1 nCoV-19 (AstraZeneca/University of Oxford, AZ), Gam-COVID-Vac (Sputnik V, SpV) or combined vaccines (mostly SpV and mRNA-1273, Moderna). The antibody response was analysed several days after the initial vaccination (20, 40, 120 and 180 days).

RESULTS

After receiving at least one dose of the COVID-19 vaccine, we detected 93.34% of seroprevalence. Previously SARS-CoV-2 infected showed higher antibody concentrations compared with naïve vaccinees. Six months after the initial vaccination, combined vaccination induced higher anti-SARS-CoV-2 antibody levels than the other vaccines in naïve volunteers. However, we did not find differences in the neutralising responses after any vaccine from naïve vaccines or between the naïve and previously infected volunteers on day 120 after vaccination.

CONCLUSIONS

Our long-term analysis of volunteers from the educational system provides data in a real-world context, showing the benefits of a boost dose still in previously infected volunteers, and suggesting the advantages of a heterologous prime-boost schedule.

Safety and immunogenicity of an inactivated whole virion SARS-CoV-2 vaccine, TURKOVAC, in healthy adults: Interim results from randomised, double-blind, placebo-controlled phase 1 and 2 trials

BACKGROUND

Development of safe and effective vaccine options is crucial to the success of fight against COVID-19 pandemic. Herein, we report interim safety and immunogenicity findings of the phase 1&2 trials of ERUCoV-VAC, an inactivated whole virion SARS-CoV-2 vaccine.

METHODS

Double-blind, randomised, single centre, phase 1 and 2 trials included SARS-CoV-2 seronegative healthy adults aged 18-55 years (18-64 in phase 2). All participants, except the first 4 in phase 1 who received ERUCoV-VAC 3 μg or 6 μg unblinded and monitored for 7 days for safety purposes, were assigned to receive two intramuscular doses of ERUCoV-VAC 3 μg or 6 μg (an inactivated vaccine containing alhydrogel as adjuvant) or placebo 21 days apart (28 days in phase 2) according to computer-generated randomisation schemes. Both trials are registered at ClinicalTrials.gov (phase 1, NCT04691947 and phase 2, NCT04824391).

RESULTS

Forty-four participants (3 μg [n:17], 6 μg [n:17], placebo [n:10]) in phase 1 and 250 (3 μg [n:100], 6 μg [n:100], placebo [n:50]) in phase 2 received ≥1 dose. In phase 1 trial, 25 adverse events AEs (80 % mild) occured in 15 participants (34.1 %) until day 43. There was no dose-response relationship noted in safety events in ERUCoV-VAC recipients (p = 0.4905). Pain at injection site was the most common AE (9/44;20.5 %). Both doses of ERUCoV-VAC 3 μg and 6 μg groups were comparable in inducing SARS-CoV-2 wild-type neutralising antibody (MNT50): GMTs (95 %CI) were 8.3 (6.4-10.3) vs. 8.6 (7.0-10.2) at day 43 (p = 0.7357) and 9.7 (6.0-13.4) vs. 10.8 (8.8-12.8) at day 60 (p = 0.8644), respectively. FRNT50 confirmed MNT50 results: SARS-CoV-2 wild-type neutralising antibody GMTs (95 %CI) were 8.4 (6.3-10.5) vs. 9.0 (7.2-10.8) at day 43 (p = 0.5393) and 11.0 (7.0-14.9) vs. 12.3 (10.3-14.5) at day 60 (p = 0.8578). Neutralising antibody seroconversion rates (95 %CI) were 86.7 % (59.5-98.3) vs 94.1 % (71.3-99.8) at day 43 (p = 0.8727) and 92.8 % (66.1-99.8) vs. 100 % (79.4-100.0) at day 60 (p = 0.8873), in ERUCoV-VAC 3 μg and 6 μg groups, respectively. In phase 2 trial, 268 AEs, (67.2 % moderate in severity) occured in 153 (61.2 %) participants. The most common local and systemic AEs were pain at injection site (23 events in 21 [8.4 %] subjects) and headache (56 events in 47 [18.8 %] subjects), respectively. Pain at injection site was the only AE with a significantly higher frequency in the ERUCoV-VAC groups than in the placebo arm in the phase 2 study (p = 0.0322). ERUCoV-VAC groups were comparable in frequency of AEs (p = 0.4587). ERUCoV-VAC 3 μg and 6 μg groups were comparable neutralising antibody (MNT₅₀): GMTs (95 %CI) were 30.0 (37.9-22.0) vs. 34.9 (47.6-22.1) at day 43 (p = 0.0666) and 34.2 (23.8-44.5) and 39.6 (22.7-58.0) at day 60, (p = 0.2166), respectively. FRNT50 confirmed MNT50 results: SARS-CoV-2 wildtype neutralising antibody GMTs were 28.9 (20.0-37.7) and 30.1 (18.5-41.6) at day 43 (p = 0.3366) and 34.2 (23.8-44.5) and 39.6 (22.7-58.0) at day 60 (p = 0.8777). Neutralising antibody seroconversion rates (95 %CI) were 95.7 % (91.4-99.8) vs. 98.9 % (96.9-100.0) at day 43 (p = 0.8710) and 96.6 % (92.8-100.0) vs 98.9 % (96.7-100.0) at day 60 (p = 0.9129) in ERUCoV-VAC 3 μg and 6 μg groups, respectively.

CONCLUSIONS

Two-dose regimens of ERUCoV-VAC 3 μg and 6 μg 28 days both had an acceptable safety and tolerability profile and elicited comparable neutralising antibody responses and seroconversion rates exceeding 95 % at day 43 and 60 after the first vaccination. Data availability Data will be made available on request.

Sleep quality was associated with adverse reactions after coronavirus disease 2019 vaccination among healthcare workers: A longitudinal paired study

Background

Many countries have currently relied on various types of vaccines for the public to control the coronavirus disease 2019 (COVID-19) pandemic. The adverse reactions (ARs) after vaccination may affect vaccination coverage and confidence. However, whether sleep quality was associated with ARs after vaccination remains unclear.

Methods

We designed a longitudinal paired study within a hospital setting. We collected data about the side effects within 7 days after two doses of scheduled vaccination among healthcare workers (HCWs). All HCWs were asked to complete a sleep survey indexed by the Pittsburgh Sleep Quality Index (PSQI) before vaccination and after a 1-month follow-up. Then, we explored the relationship between sleep quality before or after vaccination and the occurrence of ARs.

Results

A total of 345 HCWs were recruited to receive COVID-19 vaccination. The sleep quality became worse after vaccination. All local and systemic reactions were mild or moderate in severity (32.46%), and no serious adverse event was reported. Binary logistic regression showed participants with poor sleep quality (PSQI > 5) than good sleep quality (PSQI ≤ 5) before the two doses of vaccination, respectively, exhibited 1.515 and 1.107 times risk of ARs after each vaccination (both p < 0.001).

Conclusion

There is an apparently complex bidirectional relationship between sleep quality and COVID-19 vaccination adverse effects. Poor sleep quality significantly increases the risk of mild ARs after vaccination, while vaccination may cause a temporary decline in sleep quality.

Neutralizing antibodies and T-cell responses to inactivated SARS-CoV-2 vaccine in COVID-19 convalescents one and a half years after infection

Vaccines have been considered the most promising solution for ending the coronavirus disease 2019 (COVID-19) pandemic. Information regarding neutralizing antibodies (NAbs) and T-cell immune response in inactivated SARS-CoV-2 vaccine-immunized COVID-19 convalescent patients were either only available for a short time after illness recovered or not available at all (T-cell immunity). We evaluated SARS-CoV-2 NAbs and cellular immune responses to the SARS-CoV-2 inactivated vaccine in convalescent patients who recovered from infection for about one and a half years. We found that compared to before vaccination, SARS-CoV-2 NAbs and specific T-cell responses were significantly boosted by the inactivated vaccine in convalescent patients, which confirmed the pre-existing adaptive immunity in SARS-CoV-2 infected people. We observed that NAbs and IFN-γ-secreting T-cell response elicited by a single vaccine dose in subjects with prior COVID-19 infection were higher than after two doses of vaccine in SARS-CoV-2 naïve subjects. Both humoral and cellular immune responses elicited by one and two doses of inactivated vaccine were comparable in COVID-19-recovered persons. In conclusion, inactivated COVID-19 vaccine induced robust NAbs and T-cell responses to SARS-CoV-2 in COVID-19 convalescent patients and immune responses after one dose were equal to that after receiving two doses, which highlighted that robust humoral and cellular immune response can be reactivated by the inactivated vaccine in SARS-CoV-2 convalescent patients.

Side Effects Comparison of Coronavirus Vaccines Among Healthcare Workers in Shoushtar, Iran

Objective

Vaccination is one of the effective ways to fight against COVID-19 disease. Various vaccines have been designed during the coronavirus pandemic. Each of the used vaccines has beneficial effects as well as side effects. Healthcare workers were among the first vaccinated persons against COVID-19 in different countries. The current study aims to compare the side effects of AstraZeneca, Sinopharm, Bharat, and Sputnik V on healthcare workers in Iran.

Methods

This descriptive study was conducted from July 2021 to January 2022 on 1639 healthcare workers who received the COVID-19 vaccines. Data were collected using a checklist that contained questions related to systemic, local, and severe side effects of the vaccine. The collected data were analyzed using the Kruskal-Wallis, Chi-square, and trend chi-square. P < .05 was regarded as a significant statistical difference.

Results

The most commonly injected vaccines were Sinopharm (41.80%), Sputnik V (36.65%), AstraZeneca (17.75%), and Bharat (3.80%), respectively. At least 37.5% of participants reported one complication. The most common side effects after 72 hours of the first and second doses were as follows: injection site pain, fatigue, fever, myalgia, headache, and chill. Overall complication rates were reported as follows: AstraZeneca (91.4%), Sputnik V (65.9%), Sinopharm (56.8%), and Bharat (98.4%). Bharat showed the highest overall side effects, while Sinopharm had the lowest overall side effects. Also, our results indicated that individuals with a previous history of positive COVID-19 infection had a higher rate of overall complications.

Conclusions

The majority of participants did not show life-threatening side effects after the injection of 1 of the 4 studied vaccines. Since it was well accepted and tolerable by the participants, it can be used widely and safely against SARS-CoV-2.

Immunogenicity of Inactivated SARS-CoV-2 Vaccine (BBIBP-CorV; Sinopharm) and Short-Term Clinical Outcomes in Vaccinated Solid Organ Transplant Recipients: A Prospective Cohort Study

BackgroundImmunocompromised patients have lower seroconversion rate in response to COVID-19 vaccination. The aim of this study is to evaluate the humoral immune response with short-term clinical outcomes in solid organ transplant recipients vaccinated with SARS-CoV-2 vaccine (BBIBP-CorV; Sinopharm).MethodsThis prospective cohort was conducted from March to December 2021 in Abu Ali Sina hospital, Iran. All transplant recipients, older than 18 years were recruited. The patients received two doses of Sinopharm vaccine 4 weeks apart. Immunogenicity was evaluated through assessment of antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 after the first and second dose of vaccine. The patients were followed up for 6 months after vaccination.ResultsOut of 921 transplant patients, 115 (12.5%) and 239 (26%) had acceptable anti S-RBD immunoglobulin G (IgG) levels after the first and second dose, respectively. Eighty patients (8.68%) got infected with COVID-19 which led to 45 (4.9%) of patients being hospitalized. None of the patients died during follow-up period. Twenty-four (10.9%) liver transplant recipients developed liver enzyme elevation, and increased serum creatinine was observed in 86 (13.5%) kidney transplant patients. Two patients experienced biopsy-proven rejection without any graft loss.ConclusionOur study revealed that humoral response rate of solid organ transplant recipients to Sinopharm vaccine was low.

The third inactivated vaccine booster dramatically enhanced SARS-CoV-2 antibody responses and did not influence the profile of prothrombotic antibody

The purpose of this study is to investigate the production of both severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-specific antibodies and autoantibodies in serum following the third booster vaccination of the inactivated COVID-19 vaccine, and to study the effect of B cell subsets with CD27 and CD38 phenotypes in peripheral blood on antibody production. Routine blood indexes, SARS-CoV-2 antibodies, platelet factor 4 and seven antiphospholipid antibodies were detected both before and 2 months after vaccination in the medical staff of the Zhongnan Hospital of Wuhan University. Peripheral blood B cell subtypes were detected before vaccination. Following immunization, the positive rate of anti-N-S1 immunoglobulin (IgG) had increased from 24.8% to 91.3% and the average antibody concentration had increased by 11 times. The positive rate of neutralizing antibody had increased from 24.8% to 91.3%, the average antibody concentration had increased by 12 times, and the primary increased anti-S1 IgG subtype was that of IgG1. Peripheral blood CD27 + CD38+ B cells were positively correlated with antibody levels after vaccination and were a predictor of the antibody response. In addition, although some indicators showed slight absolute changes, the blood parameters and antiphospholipid antibodies of most volunteers were normal both before and after COVID-19 inactivated vaccine inoculation, and there was no statistical difference in abnormal rates either before or after inoculation. Antibodies in vivo were increased after vaccination with the inactivated vaccine, and IgG1 was the main subtype involved in response to the vaccine. Vaccination with the inactivated COVID-19 vaccine did not appear to affect thrombus-related autoantibodies.

Humoral and cellular immunity of two-dose inactivated COVID-19 vaccination in Chinese children: A prospective cohort study

Children are the high-risk group for COVID-19, and in need of vaccination. However, humoral and cellular immune responses of COVID-19 vaccine remain unclear in vaccinated children. To establish the rational immunization strategy of inactivated COVID-19 vaccine for children, the immunogenicity of either one dose or two doses of the vaccine in children was evaluated. A prospective cohort study of 322 children receiving inactivated COVID-19 vaccine was established in China. The baseline was conducted after 28 days of the first dose, and the follow-up was conducted after 28 days of the second dose. The median titers of receptor binding domain (RBD)-IgG, and neutralizing antibody (NAb) against prototype strain and Omicron variant after the second dose increased significantly compared to those after the first dose (first dose: 70.0, [interquartile range, 30.0-151.0] vs. second dose: 1261.0 [636.0-2060.0] for RBD-IgG; 2.5 [2.5-18.6] vs. 252.0 [138.6-462.1] for NAb against prototype strain; 2.5 [2.5-2.5] vs. 15.0 [7.8-26.5] for NAb against Omicron variant, all p < 0.05). The flow cytometry results showed that the first dose elicited SARS-CoV-2 specific cellular immunity, while the second dose strengthened SARS-CoV-2 specific IL-2⁺ or TNF-α⁺  monofunctional, IFN-γ⁺ TNF-α⁺  bifunctional, and IFN-γ^- IL-2⁺ TNF-α⁺ multifunctional CD4⁺ T cell responses (p < 0.05). Moreover, SARS-CoV-2 specific memory T cells were generated after the first vaccination, including the central memory T cells and effector memory T cells. The present findings provide scientific evidence for the vaccination strategy of the inactive vaccines among children against COVID-19 pandemic.

Impact of inactivated vaccines on decrease of viral RNA levels in individuals with the SARS-CoV-2 Omicron (BA.2) variant: A retrospective cohort study in Shanghai, China

Background

SARS-CoV-2 Omicron (BA.2) has stronger infectivity and more vaccine breakthrough capability than previous variants. Few studies have examined the impact of inactivated vaccines on the decrease of viral RNA levels in individuals with the Omicron variant, based on individuals' continuous daily cycle threshold (Ct) values and associated medical information from the infection to hospital discharge on a large population.

Methods

We extracted 39,811 individuals from 174,371 Omicron-infected individuals according to data inclusion and exclusion criteria. We performed the survival data analysis and Generalized Estimating Equation to calculate the adjusted relative risk (aRR) to assess the effect of inactivated vaccines on the decrease of viral RNA levels.

Results

Negative conversion was achieved in 54.7 and 94.3% of all infected individuals after one and 2 weeks, respectively. aRRs were shown weak effects on turning negative associated with vaccinations in asymptomatic infections and a little effect in mild diseases. Vaccinations had a protective effect on persistent positivity over 2 and 3 weeks. aRRs, attributed to full and booster vaccinations, were both around 0.7 and had no statistical significance in asymptomatic infections, but were both around 0.6 with statistical significance in mild diseases, respectively. Trends of viral RNA levels among vaccination groups were not significant in asymptomatic infections, but were significant between unvaccinated group and three vaccination groups in mild diseases.

Conclusion

Inactivated vaccines accelerate the decrease of viral RNA levels in asymptomatic and mild Omicron-infected individuals. Vaccinated individuals have lower viral RNA levels, faster negative conversion, and fewer persisting positive proportions than unvaccinated individuals. The effects are more evident and significant in mild diseases than in asymptomatic infections.

Efficacy and safety of COVID-19 vaccines for patients with spinal tumors receiving denosumab treatment: An initial real-clinical experience study

Background

Even if COVID-19 vaccine has gradually been adopted in the world, information of side effects and crosstalk in patients with spinal tumors is absent due to the exclusion from clinical research. In this research, we aimed to investigate the efficacy and safety for the patients with spinal tumors treated by denosumab.

Methods

In this retrospective research, 400 patients under treatment of denosumab against spinal tumors in real-clinical experience were grouped into two cohorts according to the treatment of COVID-19 vaccine. And linked hospital data, serum samples and unsolicited related adverse events had been collected from January 22nd 2021 to June 1st 2021 respectively.

Results

233 patients of all participants who received regular treatment of denosumab were vaccinated by mRNA or inactivated vaccine. Patients of metastatic disease and primary osseous spinal tumor showed similar distribution in both two groups. Over the study period, within 176 patients tested the status of serologic response of vaccine, 88(81.48%) and 41(87.23%) individuals injected one or two inactivated vaccines had effective antibody against SARS-CoV-2 infections. As 21 patients (85.71%) treated by mRNA vaccine did. Considering of the safety of vaccine, most common systemic adverse events were nausea or vomiting (45 events vs 23events). Interestingly, fewer participants in the vaccine group were statistically recorded in local adverse events than in the placebo group (16 events vs 33 events).

Conclusions

Our initial real-clinical experience suggests that COVID-19 vaccines are likely safe and effective in in patients with spinal tumors receiving denosumab treatment.

COVID-19 Vaccination Hesitancy: A Review of the Literature and Recommendations

Vaccines are important to improve immunity against pathogens and diseases. The current COVID-19 disease is rapidly evolving and spreading among people; therefore, it is important to utilize a proper vaccination strategy against it. Currently, many approved vaccines are available and accessible; however, there is a reported hesitancy against taking them among the public and even the health care workers. Mainly, this is attributed to the fear of the possible side effects and complications. Moreover, inaccurate knowledge disseminated through the media/social media especially by those who lack the proper expertise, adds confusion and more fear that affects the vaccination decision. For such reasons, it is essential to find strategies to increase the acceptability of vaccines and enhance confidence in the vaccination process. This should be accompanied by sufficient efforts and proper clinical studies to confirm the value and the safety of the vaccines. Those strategies are important to avoid the further spread of the COVID-19 disease and abort the pandemic worldwide, especially when considering the likely approach towards a COVID-19 booster vaccination program, in which booster vaccines are re-taken along intervals to adequately contain the rapidly evolving nature of the virus. This review article highlights the factors influencing the acceptability of the COVID-19 vaccination and enrollment in clinical trials among the public and some specific populations. Furthermore, it summarizes the suggested strategies and recommendations to improve attitudes towards COVID-19 vaccination programs.

SARS-CoV-2 Vaccines: Types, Working Principle, and Its Impact on Thrombosis and Gastrointestinal Disorders

In the current scenario of the coronavirus pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), considerable efforts have been made to control the pandemic by the development of a strong immune system through massive vaccination. Just after the discovery of the genetic sequences of SARS-CoV-2, the development of vaccines became the prime focus of scientists around the globe. About 200 SARS-CoV-2 candidate vaccines have already been entered into preclinical and clinical trials. Various traditional and novel approaches are being utilized as a broad range of platforms. Viral vector (replicating and non-replicating), nucleic acid (DNA and RNA), recombinant protein, virus-like particle, peptide, live attenuated virus, an inactivated virus approaches are the prominent attributes of the vaccine development. This review article includes the current knowledge about the platforms used for the development of different vaccines, their working principles, their efficacy, and the impacts of COVID-19 vaccines on thrombosis. We provide a detailed description of the vaccines that are already approved by administrative authorities. Moreover, various strategies utilized in the development of emerging vaccines that are in the trial phases along with their mode of delivery have been discussed along with their effect on thrombosis and gastrointestinal disorders.

The prevalence of adverse reactions among individuals with three-dose COVID-19 vaccination

BACKGROUND

Considering the adverse reactions to vaccination against coronavirus disease 2019 (COVID-19), some people, particularly the elderly and those with underlying medical conditions, are hesitant to be vaccinated. This study aimed to explore the prevalence of adverse reactions and provide direct evidence of vaccine safety, mainly for the elderly and people with underlying medical conditions, to receive COVID-19 vaccination.

METHODS

From 1st March to 30th April 2022, we conducted an online survey of people who had completed three doses of COVID-19 vaccination by convenience sampling. Adverse reaction rates and 95% confidence intervals were calculated. In addition, conditional logistic regression was used to compare the differences in adverse reactions among the elderly and those with underlying medical conditions with the general population.

RESULTS

A total of 3339 individuals were included in this study, of which 2335 (69.9%) were female, with an average age of 32.1 ± 11.4 years. The prevalence of adverse reactions after the first dose of inactivated vaccine was 24.6% (23.1-26.2%), 19.2% (17.8-20.7%) for the second dose, and 19.1% (17.7-20.6%) for the booster dose; among individuals using messenger RNA vaccines, the prevalence was 42.7% (32.3-53.6%) for the first dose, 47.2% (36.5-58.1%) for the second dose, and 46.1% (35.4-57.0%) for the booster dose. Compared with the general population, the prevalence of adverse events did not differ in individuals with underlying medical conditions and those aged 60 and above.

CONCLUSIONS

For individuals with underlying medical conditions and those aged 60 and above, the prevalence of adverse reactions is similar to that of the general population, which provides a scientific basis regarding vaccination safety for these populations.

Effects of inactivated SARS-CoV-2 vaccination on male fertility: A retrospective cohort study

Numerous studies have revealed severe damage to male fertility from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, raising concerns about the potential adverse impact on reproductive function of the coronavirus disease 2019 (COVID-19) vaccine developed based on the virus. Interestingly, there are several researchers who have studied the impact of the COVID-19 mRNA vaccine since then but have come up with conflicting results. As a near-ideal candidate for mass immunization programs, inactivated SARS-CoV-2 vaccine has been widely used in many countries, particularly in less wealthy nations. However, little is known about its effect on male fertility. Here, we conducted a retrospective cohort study at a single large center for reproductive medicine in China between December 2021 and August 2022. Five hundred and nineteen fertile men with no history of laboratory-confirmed COVID-19 were included and categorized into four groups based on their vaccination status: unvaccinated group (n = 168), one-dose vaccinated group (n = 8), fully vaccinated group (n = 183), and booster group (n = 160). All of them underwent a semen analysis and most had serum sex hormone levels tested. There were no significant differences in all semen parameters and sex hormone levels between the unvaccinated group and either vaccinated group. To account for possible vaccination-to-test interval-specific changes, sub-analyses were performed for two interval groups: ≤90 and >90 days. As expected, most of the semen parameters and sex hormone levels remained unchanged between the control and vaccinated groups. However, participants in vaccinated group (≤90 days) have decreased total sperm motility and increased follicle-stimulating hormone level compared with the ones in unvaccinated group. Moreover, some trends similar to those found during COVID-19 infection and recovery were observed in our study. Fortunately, all values are within the normal range. In addition, vaccinated participants reported few adverse reactions. No special medical intervention was required, and no serious adverse reactions happened. Our study suggests that inactivated SARS-CoV-2 vaccination does not impair male fertility, possibly due to the low frequency of adverse effects. This information reassures young male population who got this vaccine worldwide, and helps guide future vaccination efforts.

Cardiovascular complications of COVID-19 vaccines: A review of case-report and case-series studies

BACKGROUND

There are multiple reviews on cardiovascular aspects of COVID-19 disease on cardiovascular system in different population but there is lack of evidence about cardiovascular adverse effects of COVID vaccines.

OBJECTIVES

The purpose of this study was to compare the cardiac complications of COVID19 vaccines, based on vaccine type (mRNA, vector-based, and inactivated vaccines).

METHODS

A systematic search was performed covering PubMed for English case-reports and case-series studies, and finally 100 studies were included.

RESULTS

Myocarditis (with overall rate around 1.62%) was shown to be the most common post-COVID19 immunization cardiac event. More than 90% of post-COVID19 vaccination myocarditis occurred after receiving mRNA vaccines (Moderna & Pfizer-BioNTech), but the report of this event was less in the case of vector-based vaccinations and/or inactivated vaccines. Myocarditis was reported more commonly in men and following the second dose of the immunization. Takotsubo cardiomyopathy (TTC) was reported after mRNA (more commonly) and vector-based vaccinations, with no case report after inactivated vaccines. When mRNA and vector-based vaccinations were used instead of inactivated vaccines, a greater frequency of vaccine-induced thrombotic thrombocytopenia (VITT) and pulmonary emboli (PE) was reported. Myocardial infarction/cardiac arrest was recorded in those beyond the age of 75 years.

CONCLUSION

The personal and public health benefits of COVID-19 vaccination much outweigh the minor cardiac risks. Reporting bias, regarding more available mRNA vaccines in developed countries, may conflict these results.

Safety and Immunogenicity of Inactivated SARS-CoV-2 Vaccine (BBIBP-CorV) in Hypertensive and/or Diabetic People Aged over 60 Years: A Prospective Open-Label Study

AIMS

Severe acute respiratory syndrome coronavirus type 2 (SARS-COV-2) infection may increase the risk of developing dangerous symptoms among the elderly with underlying medical conditions. The aim of this study was to evaluate the safety and immunogenicity of the SARS-CoV-2 inactivated vaccine (Vero) in patients over 60 years of age with hypertension and/or diabetes.

METHODS

An open-label, multi-center, prospective clinical trial was conducted at three medical sites in Fujian, China. Participants aged 60 years and above with hypertension, diabetes, and healthy controls were included in four groups: hypertension, diabetes, combined disease, and healthy controls. Volunteers received two doses of the inactivated SARS-COV-2 vaccine (BBIBP-CorV) on days 0 and 21. Adverse events were recorded for 21 days after each dose. Blood samples were taken before the first vaccination and 28 days after the second vaccination to detect the serum conversion rate and geometric mean titer (GMT) of neutralizing antibodies.

RESULTS

A total of 480 participants (110 hypertension, 110 diabetes, 100 combined hypertension and diabetes, and 160 healthy controls) were recruited. The incidences of adverse events in the four groups were 10 (9.1%) in the hypertension group, 19 (17.3%) in the diabetes group, 11 (11.0%) in the combined disease group, and 11 (6.9%) in healthy controls, with no statistical significance (P > 0.05). At 28 days after the second vaccination, the positive conversion rates of serum neutralizing antibody in the four groups were 97.3%(107/110), 97.3% (107/110), 100.0% (99/99),and 98.7%(155/157), respectively, and the GMTs were 75.28 (95% CI 64.03-88.50), 69.4 (95% CI 59-81.63), 77.21 (95% CI 66.68-89.41), and 78.64 (95% CI 69.87-88.50), respectively. There was no significant difference in neutralizing antibody responses among the four groups (P > 0.05). Additionally, the GMT after immunization was higher in females than in males (OR = 2.59, 95% CI 1.31-5.12).

CONCLUSIONS

The BBIBP-CorV vaccine is safe and elicits an adequate antibody response in patients over 60 years of age with hypertension and/or diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT05065879.

The efficacy and effectiveness of the COVID-19 vaccines in reducing infection, severity, hospitalization, and mortality: a systematic review

With the relatively rapid development of the COVID-19 pandemic, vaccine development has become crucial for limiting disease transmission. The accelerated growth in the approved COVID-19 vaccines has sparked concerns about their efficacies which have been assessed by many studies. This systematic review compares the efficacy and effectiveness of seven COVID-19 vaccines. A comprehensive systematic literature search was performed using several databases to identify studies reporting the effectiveness or the efficacy of the vaccines. Only 42 studies met our inclusion criteria, which revealed that the COVID-19 vaccines have successfully reduced the rates of infections, severity, hospitalization, and mortality among the different populations. The full-dose regimen of the Pfizer/BioNTech vaccine is the most effective against infections with the B.1.1.7 and B.1.351 variants. Despite of the high effectiveness of some of the COVID-19 vaccines, more efforts are required to test their effectiveness against the other newly emerging variants.

Clinical characteristics and severity of beta and delta variants of SARS-CoV-2 and the effect of vaccine on delta variants

Background

The Delta variant of concern (VOC) is rapidly becoming the dominant strain globally. We report the clinical characteristics and severity of hospitalized patients infected with Delta and Beta VOCs during the local outbreak in Harbin, Heilongjiang Province, China, and the effect of vaccines on the Delta variant.

Methods

We collected a total of 735 COVID-19 patients from the First Affiliated Hospital of Harbin Medical University, including 96 cases infected with the Delta VOC and 639 cases infected with the Beta VOC. Demographic, clinical characteristic and laboratory findings were collected and compared.

Results

Differences in viral shedding, IgG and IgM levels, and the neutrophil-to-lymphocyte ratio were noted between the Delta and Beta VOCs (p < 0.05). Survival analysis of the two groups revealed longer viral shedding of the Delta VOC (p < 0.05). For the Delta VOC, the longer the vaccination period, the lower the IgG and IgM levels. IgM levels were higher in the convalescent plasma group, whereas lymphocyte counts were lower.

Conclusions

Delta VOC virus shedding was longer compared with Beta VOC shedding. Vaccination with inactivated vaccines can reduce the severe illness rate of the Delta VOC. IgG and IgM levels are reduced as the time period between the first and second vaccine doses increases.

Efficacy and Safety of COVID-19 Vaccination in Older Adults: A Systematic Review and Meta-Analysis

Objective: To analyze the differences in efficacy and safety of different types of novel coronavirus pneumonia (COVID-19) vaccines in different age groups (young adults and elderly). Methods: Randomized controlled trials (RCTs) on COVID-19 vaccine in PubMed, Embase, Web of Science, and Cochrane library were searched by computer, and eight eligible studies were analyzed. Meta-analysis was performed using Stata 16.0 and RevMan5.4 software. Results: The mean geometric titer (GMT) of the virus in the elderly was significantly higher than that in the placebo group (SMD = 0.91, 95% CI (0.68, 1.15), p < 0.01), presenting no obvious difference compared with the young adults (SMD = 0.19, 95% CI (0.38, 0.01), p = 0.06). Meanwhile, the effect of multiple vaccinations was better than that of single vaccination (SMD = 0.83, 95% CI (0.33, 1.34), p < 0.01). However, the number of adverse events (AEs) in the elderly was lower than that in the young adults (OR = 0.35, 95% CI (0.29, 0.42), p < 0.01). Conclusions: The immunization effect of COVID-19 vaccine in the elderly is obvious, especially after multiple vaccinations, and the incidence of AEs in the elderly is low, which proves that the vaccination of the elderly is safe and effective.

Health Consequences of University Employees Post-COVID-19 Vaccination at Palestinian Universities

Introduction

The control of vaccine hesitancy comes with key protective measures against coronavirus disease (COVID-19) and excellent efficacy in clinical trials and effectiveness in real-world data. However, some people believe that vaccination is ineffective and it causes health problems. This study aimed to assess the health consequences of university employees' post-COVID-19 vaccination at Palestinian universities.

Method

A cross-sectional study was conducted between February and June 2021. A total of 310 university employees participated from six universities in Palestine. A self-reported questionnaire was used for data collection and included the following: personal characteristics of university employees, knowledge about COVID-19 vaccination, medical background of the participant, and their perception regarding receiving the COVID-19 vaccination.

Results

The results revealed that 32.6% and 43.2%of the participants had fever post the first and second doses, respectively. Also, 49.0% and 39.4% of them complained of exhaustion or fatigue and headache post the first dose and 58.1% and 46.1% had exhaustion or fatigue and pain in their muscles post the second dose, respectively. In addition, 29.2% and 16.7% of them had respiratory and digestive problems post the first dose and 38.9% and 19.0% had problems in respiratory and digestive respectively post the second dose. Furthermore, the analysis revealed that fever, symptoms at (the injection site), and exposure to physical symptoms have significant differences between the first dose and second doses of the vaccine (p < .001).

Conclusion

This study confirmed that the respiratory and digestive problems are the main problems post-COVID-19 vaccination. Also, this study confirmed that fever, symptoms at (the injection site), and exposure to physical symptoms have significant differences between the first dose and second dose of the vaccine.

Short-term Side Effects of COVID-19 Vaccines (Astrazeneca, Sputnik-V, and Sinopharm) in Health Care Workers: A Cross-Sectional Study in Iran

Background: The occurrence of side effects of vaccines plays an important role in their acceptance by people. Therefore, the aim of this study was to evaluate the side effects of COVID-19 vaccines (Sputnik-V, AstraZeneca, and Sinopharm) in Neyshabur health care workers (HCWs). Methods: A cross-sectional study was performed to evaluate the side effects of COVID-19 vaccines among the HCWs of the Neyshabur University of Medical Sciences from July 31, 2021, to September 6, 2021, by using a self-report checklist. We sent our checklist via an internet link to collect data such as demographic data of participants, previous COVID-19 infection (PCR+), vaccine information and side effects of vaccines. Mean, median and standard deviation were used to determine descriptive statistics and a logistic regression model was also used to determine the relationship between the type of vaccine and its side effects. Results: 317 participants filled out the checklist; among them 47% (N= 149), 21.14% (N= 67), and 31.86% (N= 101) have been vaccinated with Sputnik-V, AstraZeneca, and Sinopharm, respectively. The percentage of side effects after the first dose was 62.15% (N= 197). The Percentage of local side effects was 76% (N= 241) and systemic side effects were 29.36% (N= 95). The most common side effects in all three vaccines were injection site pain (75.08%, N= 240), muscle pain (62.46%, N=198) and headache (52.05%, N=165). Also, the odds ratio of injection site pain, chill and sweating in those who received the AstraZeneca vaccine was 3.9(95% CI, 1.7-9.3), 3.7 (95% CI, 1.8-7.3), and 3.2 (95% CI, 1.7-63), of those who received the Sputnik V vaccine (p ≤ 0.001). Conclusion: The most common side effects among our participants were injection site pain, muscle pain, and headache. Most of the post-vaccination side effects are mild to moderate in severity and self-limited. Reported side effects were more common in recipients with AstraZeneca than in those with Sputnik-V and Sinopharm.

Efficacy and Short-Term Safety of COVID-19 Vaccines: A Cross-Sectional Study on Vaccinated People in the UAE

BACKGROUND

The emergence of COVID-19 has been a major challenge to public health and the world economy. During a wave of COVID-19, the usage of widespread vaccination procedures and broader coverage to the whole of humanity will be made possible if the general population has access. An intended effect of vaccination is to provide "herd immunity," which protects those who have not been vaccinated along with those who have been. However, some concerns regarding the safety and efficacy of COVID-19 vaccines were raised.

AIM

This study aims to provide evidence on the short-term safety and efficacy of four types of vaccines that are officially approved by the Ministry of Health in the United Arab Emirates (UAE). These include Sinopharm, Sputnik V, Pfizer, and AstraZeneca.

METHOD

This study utilized a cross-sectional descriptive design. Data on the efficacy and short-term protection of COVID-19 vaccines on vaccinated citizens and residents (n = 764) of the UAE were collected between February and April 2021. Participants were conveniently approached using a Google Forms survey, where they responded to a semi-structured questionnaire pertaining to socio-demographic questions and in-depth questions related to COVID-19, including whether they suffer from any comorbidities, the most commonly encountered post-vaccination side effects, and the severity of their symptoms, using a 5-point Likert scale. Results were analyzed using SPSS version 24, calculations of p-values and descriptive statistics were used for data differentiation.

RESULTS

The majority of the participants (n = 612 or 94.4%) stated that they did not become reinfected after receiving two doses of COVID-19 vaccine. In addition, the incidence of being hospitalized after vaccination was negligible. In terms of adverse effects, the most common individually reported side effects, regardless of the vaccination type, included "pain at the site of injection", followed by "general fatigue", then "lethargy". Moreover, most of these side effects occurred after the second dose of the vaccine, irrespective of the type of vaccine. Females were found to be more susceptible to the adversities of COVID-19 vaccination. The occurrence of side effects was not found to be related to the nationality/ethnicity of the vaccine recipient. Furthermore, none of the vaccines affected sleep pattern, since a significant number of respondents reported a regular sleep pattern after being vaccinated. The majority respondents who received two doses of vaccination (n = 585 or 76.6%) reported that they did not become infected post vaccination, regardless the type of vaccine received, whereas only (n = 11 or 1.9%) were reinfected with COVID-19 after 2-4 weeks.

CONCLUSION

The findings of this study suggest that vaccines can offer short-term protection against COVID-19 reinfection. Moreover, both the first- and second-vaccination side effects were described as very mild to moderate, which indicates tolerability. These data may strengthen the public confidence in receiving vaccinations.

Intranasal SARS-CoV-2 RBD decorated nanoparticle vaccine enhances viral clearance in the Syrian hamster model

Multiple vaccines have been developed and licensed for SARS-CoV-2. While these vaccines reduce disease severity, they do not prevent infection, and SARS-CoV-2 continues to spread and evolve. To prevent infection and limit transmission, vaccines must be developed that induce immunity in the respiratory tract. Therefore, we performed proof-of-principle vaccination studies with an intranasal nanoparticle vaccine against SARS-CoV-2. The vaccine candidate consisted of the self-assembling 60-subunit I3-01 protein scaffold covalently decorated with the SARS-CoV-2 receptor binding domain (RBD) using the SpyCatcher-SpyTag system. We verified the intended antigen display features by reconstructing the I3-01 scaffold to 3.4A using cryo-EM, and then demonstrated that the scaffold was highly saturated when grafted with RBD. Using this RBD-grafted SpyCage scaffold (RBD+SpyCage), we performed two unadjuvanted intranasal vaccination studies in the "gold-standard" preclinical Syrian hamster model. Hamsters received two vaccinations 28 days apart, and were then challenged 28 days post-boost with SARS-CoV-2. The initial study focused on assessing the immunogenicity of RBD+SpyCage, which indicated that vaccination of hamsters induced a non-neutralizing antibody response that enhanced viral clearance but did not prevent infection. In an expanded study, we demonstrated that covalent bonding of RBD to the scaffold was required to induce an antibody response. Consistent with the initial study, animals vaccinated with RBD+SpyCage more rapidly cleared SARS-CoV-2 from both the upper and lower respiratory tract. These findings demonstrate the intranasal SpyCage vaccine platform can induce protection against SARS-CoV-2 and, with additional modifications to improve immunogenicity, is a versatile platform for the development of intranasal vaccines targeting respiratory pathogens.

COVID-19 vaccination boosts the potency and breadth of the immune response against SARS-CoV-2 among recovered patients in Wuhan

The immunity of patients who recover from coronavirus disease 2019 (COVID-19) could be long lasting but persist at a lower level. Thus, recovered patients still need to be vaccinated to prevent reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or its mutated variants. Here, we report that the inactivated COVID-19 vaccine can stimulate immunity in recovered patients to maintain high levels of anti-receptor-binding domain (RBD) and anti-nucleocapsid protein (NP) antibody titers within 9 months, and high neutralizing activity against the prototype, Delta, and Omicron strains was observed. Nevertheless, the antibody response decreased over time, and the Omicron variant exhibited more pronounced resistance to neutralization than the prototype and Delta strains. Moreover, the intensity of the SARS-CoV-2-specific CD4+ T cell response was also increased in recovered patients who received COVID-19 vaccines. Overall, the repeated antigen exposure provided by inactivated COVID-19 vaccination greatly boosted both the potency and breadth of the humoral and cellular immune responses against SARS-CoV-2, effectively protecting recovered individuals from reinfection by circulating SARS-CoV-2 and its variants.

Efficacy and safety of COVID-19 vaccines

BACKGROUND

Different forms of vaccines have been developed to prevent the SARS-CoV-2 virus and subsequent COVID-19 disease. Several are in widespread use globally.  OBJECTIVES: To assess the efficacy and safety of COVID-19 vaccines (as a full primary vaccination series or a booster dose) against SARS-CoV-2.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register and the COVID-19 L·OVE platform (last search date 5 November 2021). We also searched the WHO International Clinical Trials Registry Platform, regulatory agency websites, and Retraction Watch.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing COVID-19 vaccines to placebo, no vaccine, other active vaccines, or other vaccine schedules.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. We used GRADE to assess the certainty of evidence for all except immunogenicity outcomes.  We synthesized data for each vaccine separately and presented summary effect estimates with 95% confidence intervals (CIs).  MAIN RESULTS: We included and analyzed 41 RCTs assessing 12 different vaccines, including homologous and heterologous vaccine schedules and the effect of booster doses. Thirty-two RCTs were multicentre and five were multinational. The sample sizes of RCTs were 60 to 44,325 participants. Participants were aged: 18 years or older in 36 RCTs; 12 years or older in one RCT; 12 to 17 years in two RCTs; and three to 17 years in two RCTs. Twenty-nine RCTs provided results for individuals aged over 60 years, and three RCTs included immunocompromized patients. No trials included pregnant women. Sixteen RCTs had two-month follow-up or less, 20 RCTs had two to six months, and five RCTs had greater than six to 12 months or less. Eighteen reports were based on preplanned interim analyses. Overall risk of bias was low for all outcomes in eight RCTs, while 33 had concerns for at least one outcome. We identified 343 registered RCTs with results not yet available.  This abstract reports results for the critical outcomes of confirmed symptomatic COVID-19, severe and critical COVID-19, and serious adverse events only for the 10 WHO-approved vaccines. For remaining outcomes and vaccines, see main text. The evidence for mortality was generally sparse and of low or very low certainty for all WHO-approved vaccines, except AD26.COV2.S (Janssen), which probably reduces the risk of all-cause mortality (risk ratio (RR) 0.25, 95% CI 0.09 to 0.67; 1 RCT, 43,783 participants; high-certainty evidence). Confirmed symptomatic COVID-19 High-certainty evidence found that BNT162b2 (BioNtech/Fosun Pharma/Pfizer), mRNA-1273 (ModernaTx), ChAdOx1 (Oxford/AstraZeneca), Ad26.COV2.S, BBIBP-CorV (Sinopharm-Beijing), and BBV152 (Bharat Biotect) reduce the incidence of symptomatic COVID-19 compared to placebo (vaccine efficacy (VE): BNT162b2: 97.84%, 95% CI 44.25% to 99.92%; 2 RCTs, 44,077 participants; mRNA-1273: 93.20%, 95% CI 91.06% to 94.83%; 2 RCTs, 31,632 participants; ChAdOx1: 70.23%, 95% CI 62.10% to 76.62%; 2 RCTs, 43,390 participants; Ad26.COV2.S: 66.90%, 95% CI 59.10% to 73.40%; 1 RCT, 39,058 participants; BBIBP-CorV: 78.10%, 95% CI 64.80% to 86.30%; 1 RCT, 25,463 participants; BBV152: 77.80%, 95% CI 65.20% to 86.40%; 1 RCT, 16,973 participants). Moderate-certainty evidence found that NVX-CoV2373 (Novavax) probably reduces the incidence of symptomatic COVID-19 compared to placebo (VE 82.91%, 95% CI 50.49% to 94.10%; 3 RCTs, 42,175 participants). There is low-certainty evidence for CoronaVac (Sinovac) for this outcome (VE 69.81%, 95% CI 12.27% to 89.61%; 2 RCTs, 19,852 participants). Severe or critical COVID-19 High-certainty evidence found that BNT162b2, mRNA-1273, Ad26.COV2.S, and BBV152 result in a large reduction in incidence of severe or critical disease due to COVID-19 compared to placebo (VE: BNT162b2: 95.70%, 95% CI 73.90% to 99.90%; 1 RCT, 46,077 participants; mRNA-1273: 98.20%, 95% CI 92.80% to 99.60%; 1 RCT, 28,451 participants; AD26.COV2.S: 76.30%, 95% CI 57.90% to 87.50%; 1 RCT, 39,058 participants; BBV152: 93.40%, 95% CI 57.10% to 99.80%; 1 RCT, 16,976 participants). Moderate-certainty evidence found that NVX-CoV2373 probably reduces the incidence of severe or critical COVID-19 (VE 100.00%, 95% CI 86.99% to 100.00%; 1 RCT, 25,452 participants). Two trials reported high efficacy of CoronaVac for severe or critical disease with wide CIs, but these results could not be pooled. Serious adverse events (SAEs) mRNA-1273, ChAdOx1 (Oxford-AstraZeneca)/SII-ChAdOx1 (Serum Institute of India), Ad26.COV2.S, and BBV152 probably result in little or no difference in SAEs compared to placebo (RR: mRNA-1273: 0.92, 95% CI 0.78 to 1.08; 2 RCTs, 34,072 participants; ChAdOx1/SII-ChAdOx1: 0.88, 95% CI 0.72 to 1.07; 7 RCTs, 58,182 participants; Ad26.COV2.S: 0.92, 95% CI 0.69 to 1.22; 1 RCT, 43,783 participants); BBV152: 0.65, 95% CI 0.43 to 0.97; 1 RCT, 25,928 participants). In each of these, the likely absolute difference in effects was fewer than 5/1000 participants. Evidence for SAEs is uncertain for BNT162b2, CoronaVac, BBIBP-CorV, and NVX-CoV2373 compared to placebo (RR: BNT162b2: 1.30, 95% CI 0.55 to 3.07; 2 RCTs, 46,107 participants; CoronaVac: 0.97, 95% CI 0.62 to 1.51; 4 RCTs, 23,139 participants; BBIBP-CorV: 0.76, 95% CI 0.54 to 1.06; 1 RCT, 26,924 participants; NVX-CoV2373: 0.92, 95% CI 0.74 to 1.14; 4 RCTs, 38,802 participants). For the evaluation of heterologous schedules, booster doses, and efficacy against variants of concern, see main text of review.

AUTHORS' CONCLUSIONS

Compared to placebo, most vaccines reduce, or likely reduce, the proportion of participants with confirmed symptomatic COVID-19, and for some, there is high-certainty evidence that they reduce severe or critical disease. There is probably little or no difference between most vaccines and placebo for serious adverse events. Over 300 registered RCTs are evaluating the efficacy of COVID-19 vaccines, and this review is updated regularly on the COVID-NMA platform (covid-nma.com). Implications for practice Due to the trial exclusions, these results cannot be generalized to pregnant women, individuals with a history of SARS-CoV-2 infection, or immunocompromized people. Most trials had a short follow-up and were conducted before the emergence of variants of concern. Implications for research Future research should evaluate the long-term effect of vaccines, compare different vaccines and vaccine schedules, assess vaccine efficacy and safety in specific populations, and include outcomes such as preventing long COVID-19. Ongoing evaluation of vaccine efficacy and effectiveness against emerging variants of concern is also vital.

SARS-CoV-2: An Analysis of the Vaccine Candidates Tested in Combatting and Eliminating the COVID-19 Virus

Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), better known as COVID-19, is a highly contagious virus, transferable via air droplets from close human-human contact. The pandemic has led to over 6.5 million deaths worldwide, making it the largest global health crisis since the influenza pandemic in 1918. SARS-CoV-2 rapidly spread around the world, forcing the World Health Organization (WHO) to deem it a global health pandemic after three months of its initiation. The virus has wreaked havoc on many countries worldwide, overwhelming healthcare systems, hence damaging many economies. Even though research has progressed the understanding of the SARS-CoV-2 virus, the information gathered about the vaccine trials and their findings have been scarcely distributed to the public in a single study. The information available to scientists has therefore given researchers a pathway to building an efficacious vehicle to substantially decrease the spread of the virus. The vaccines formulated had many challenges due to multiple factors such as viral mutations and clinical trial delays. This paper will aim to educate readers on the processes that the vaccine candidates took, and better understand the procedures; additionally, we'll look at all candidates' findings that went into clinical trials, assessing, analyzing, and evaluating the 27 vaccine candidates that went into phase III trials and the 13 candidates that went into either phase I/II trials.

The associations between COVID-19 vaccination and psychological disorders among healthcare workers in China

INTRODUCTION

COVID-19 has caused an unprecedented psychological affection that might impact the nationwide vaccination program in China. This study was to explore the association between COVID-19 vaccination and psychological disorders among healthcare workers.

METHODS

The study included 1571 healthcare workers from an anonymous online survey. Participants' sociodemographic characteristics, uptake data for the COVID-19 vaccine, and scores of the Depression, Anxiety, and Stress Scale (DASS-21) were collected. Nonparametric tests were conducted to compare the mean scores of DASS-21 between different subgroups. The potential factors related to psychological disorders of healthcare workers were analyzed using logistic regression.

RESULTS

The vaccination rate was 69.6 %, the incidence of vaccine-related adverse events was 35.13 %, and the prevalence of depression, anxiety, and stress were 24.8 %, 32 %, and 33.4 % in this study, respectively. Compared to vaccinated participants (single-dose and double-dose vaccines), unvaccinated participants got significantly higher mean scores of DASS-21 (p < 0.05 for all). Vaccinated participants who suffered no adverse events scored significantly lower than those who suffered 1-2 or ≥3 adverse events (p < 0.05 for all). Vaccination was negatively associated with higher depression, anxiety, and stress, however, the number of vaccine-related adverse events was positively associated with them.

LIMITATIONS

As this is a cross-sectional study, we could only speculate on the causality.

CONCLUSIONS

An obvious impact of the psychological disorders on the COVID-19 vaccine coverage and related adverse events was detected in this study. Public health agencies should attach great importance to the psychological states of our citizens before getting vaccinated.

Emerging COVID-19 variants and their impact on SARS-CoV-2 diagnosis, therapeutics and vaccines

The emergence of novel and evolving variants of SARS-CoV-2 has fostered the need for change in the form of newer and more adaptive diagnostic methods for the detection of SARS-CoV-2 infections. On the other hand, developing rapid and sensitive diagnostic technologies is now more challenging due to emerging variants and varying symptoms exhibited among the infected individuals. In addition to this, vaccines remain the major mainstay of prevention and protection against infection. Novel vaccines and drugs are constantly being developed to unleash an immune response for the robust targeting of SARS-CoV-2 and its associated variants. In this review, we provide an updated perspective on the current challenges posed by the emergence of novel SARS-CoV-2 mutants/variants and the evolution of diagnostic techniques to enable their detection. In addition, we also discuss the development, formulation, working mechanisms, advantages, and drawbacks of some of the most used vaccines/therapeutic drugs and their subsequent immunological impact.Key messageThe emergence of novel variants of the SARS-CoV-2 in the past couple of months, highlights one of the primary challenges in the diagnostics, treatment, as well as vaccine development against the virus.Advancements in SARS-CoV-2 detection include nucleic acid based, antigen and immuno- assay-based and antibody-based detection methodologies for efficient, robust, and quick testing; while advancements in COVID-19 preventive and therapeutic strategies include novel antiviral and immunomodulatory drugs and SARS-CoV-2 targeted vaccines.The varied COVID-19 vaccine platforms and the immune responses induced by each one of them as well as their ability to battle post-vaccination infections have all been discussed in this review.