A Comparative Study of Immunogenicity, Antibody Persistence, and Safety of Three Different COVID-19 Boosters between Individuals with Comorbidities and the Normal Population

Optimal Timing of Vaccination: A Narrative Review of Integrating Strategies for COVID-19, Influenza, and Respiratory Syncytial Virus

Lower respiratory tract infections caused by SARS-CoV-2, influenza, and respiratory syncytial virus (RSV) cause a significant disease burden globally, despite the availability of effective vaccines. Certain populations, such as older adults (≥ 60 years) and individuals of all ages with particular comorbidities, are at increased risk for severe outcomes, including hospitalization and death. National administration schedules for available vaccines against respiratory viruses are not unified, and not all current guidelines are clear and directive, concerning the optimal timing of vaccination. Herein, we formulate an evidence-based position regarding the optimal timing of COVID-19, influenza, and RSV vaccination for older adults and individuals with chronic comorbidities, based on a synthesis of the literature and current guidelines. Vaccination impact and timing were found to be influenced by vaccinee risk factors, including age and comorbidities, and waning vaccine effectiveness and seasonal pathogen burden. Because COVID-19, influenza, and RSV display unique seasonal patterns within and between regions, local epidemiological surveillance of each virus is crucial for determining optimal vaccination timing and guidelines. To maximize the benefits of these respiratory virus vaccines, the timing of peak vaccine effectiveness and period of greatest risk for severe outcomes should be aligned. Thus, COVID-19, influenza, and other recommended vaccines given ahead of the start of the respiratory virus season (or other regionally appropriate time) and co-administered at a single, routine visit represent the optimal approach to protecting at-risk populations. More data will be required to establish the clinical benefit of additional RSV vaccine doses and whether these may be integrated within a seasonal schedule. Coordinated policy decisions that align with strain selection for new and annually reformulated vaccines would enable the timely raising of public health awareness, ultimately leading to enhanced vaccine uptake. Implementation strategies will require engagement of healthcare providers and strong, evidence-based public health recommendations for integrated vaccine schedules.

Long-term assessment of anti-SARS-CoV-2 antibody levels post-pandemic: Tracking the dynamics after two, three, and four COVID-19 vaccine doses

BACKGROUND

Given the limited available data about to the number of vaccine doses administered over an extended time in Iran, the immune status of vaccinated individuals and any potential disparities in this regard among those who received different numbers of vaccine doses remain unknown. Therefore, this study aimed to assess humoral immunity of individuals who received different doses of the COVID-19 vaccines in Iran.

METHODS

This study was conducted from February, 2022 to December 2023 including 605 vaccinated subjects. The durability of anti-spike, anti-nucleocapsid (NCP), neutralizing antibody, and interferon-γ (IFN-γ) was evaluated at least 6 months after the last vaccination, as well as 60 and 120 days after it, in individuals who received two or three doses of the COVID-19 vaccine. Furthermore, the evaluation of humoral and cellular response was performed before the fourth dose (second booster) as well as 21 and 60 days thereafter.

RESULTS

The 3-dose group showed significantly higher levels of anti-spike, neutralizing antibodies, and IFN-γ compared to the 2-dose group. Both the 2-dose and 3-dose groups experienced a slight decrease in the dynamic of SARS-CoV-2 Abs, though the associated levels remained within a positive range. After receiving the fourth dose of PastoCovac, most participants had significantly high levels of anti-spike, neutralizing antibodies, and IFN-γ, regardless of the type of three-dose regimen they had previously received. The average antibody titer decreased after 60 days from the fourth dose, but remained relatively stable during the follow-up period.

CONCLUSION

This study found that the level of anti-SARS-CoV-2 antibodies and IFN-γ, as well as their durability, were still within a positive range in 2-dose and 3-dose vaccinated groups over the long-term follow-up. Furthermore, PastoCovac vaccine enhanced humoral and cellular immune responses and could be recommended as a booster dose for individuals previously vaccinated with any previously administered COVID-19 vaccine.

Circulatory microRNAs as potential biomarkers for different aspects of COVID-19

The coronavirus disease of 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can alter the expression levels of host microRNAs (miRNAs). Increasing evidence suggests that circulating miRNAs can potentially play an important role in the diagnosis and prognosis of respiratory infectious diseases, especially COVID-19, and might serve as sensitive indicators of disease before the emergence of clinical symptoms. Here, we review the potential of circulatory microRNAs as novel biomarkers for different aspects of COVID-19. Recent studies have suggested that they can be useful not only for COVID-19 prognosis but also for prediction of disease severity and mortality among intensive care unit (ICU) and ward patients. Moreover, extracellular vesicle (EV) miRNAs can be associated with antibody titer after COVID-19 vaccination. This review provides an overview of miRNA-based biomarkers.

Epidemiological and immunological characteristics of middle-aged and elderly people in housing estates after Omicron BA.5 wave in Jinan, China

A great number of COVID-19 patients was caused by Omicron BA.5 subvariant between December 2022 and January 2023 after the end of the zero-COVID-19 policy in China. In this study, we clarified the epidemiological and immunological characteristics of 457 enrolled middle-aged and elderly population in two housing estates after Omicron BA.5 wave. A total of 89.9 % (411/457) individuals have suffered Omicron BA.5 infection, among which 78.1 % (321/411) were symptomatic. The elderly patients were more likely to show fatigue and had longer symptomatic period than that of middle-aged patients post Omicron BA.5 infection. Omicron XBB and BA.2.86 subvariants extensively escaped the immunity elicited by Omicron BA.5 infection. The level of neutralizing antibody was mostly affected by vaccination doses rather than underlying disease status in these participants. It is very important to strengthen the epidemiological investigation and immune resistance assessment among elderly population for control of emerging SARS-CoV-2 variants.

Assessment of COVID-19 Vaccine Impact on Women's Menstrual Health within an 18-Month Follow-Up

Considering menstruation as a crucial factor in females' health and fertility, any factor that could change its cycle is important. This study was conducted from April 2021 to October 2022 on females who got 3 doses of vaccines against SARS-CoV-2 through different platforms. The participants were requested to provide the trained experts with any changes regarding menstrual cycles after each dose of the vaccine up to 6 months after the booster shots. The disturbances related to the vaccines were identified by the adverse events committee to find possible associations with the applied vaccines. Of 308 women who participated until the end of the study, 22 (7.1%) complained about at least one abnormality in their menstrual patterns. The most common disturbance was metrorrhagia as 10 (48%) incidences followed by menorrhagia as 6 events (24.2%). Notably, the identified complaints were persistent in 59% of the patients. In addition, 14 studied cases developed COVID-19 infection after menstrual disorders. In these cases, COVID-19 could also play a role in the persistence of postvaccine menstrual disturbances. COVID-19 vaccination could affect menstrual cycle in women with no remarkable previous medical history. More longitudinal studies are required regarding this issue.

Non-cross-reactive epitopes dominate the humoral immune response to COVID-19 vaccination - kinetics of plasma antibodies, plasmablasts and memory B cells

Introduction

COVID-19 vaccines are highly effective in inducing protective immunity. While the serum antibody response to COVID-19 vaccination has been studied in depth, our knowledge of the underlying plasmablast and memory B cell (Bmem) responses is still incomplete. Here, we determined the antibody and B cell response to COVID-19 vaccination in a naïve population and contrasted it with the response to a single influenza vaccination in a primed cohort. In addition, we analyzed the antibody and B cell responses against the four endemic human coronaviruses (HCoVs).

Methods

Measurement of specific plasma IgG antibodies was combined with functional analyses of antibody-secreting plasmablasts and Bmems. SARS-CoV-2- and HCoV-specific IgG antibodies were quantified with an in-house bead-based multiplexed immunoassay.

Results

The antibody and B cell responses to COVID-19 vaccination reflected the kinetics of a prime-boost immunization, characterized by a slow and moderate primary response and a faster and stronger secondary response. In contrast, the influenza vaccinees possessed robust immune memory for the vaccine antigens prior to vaccination, and the recall vaccination moderately boosted antibody production and Bmem responses. Antibody levels and Bmem responses waned several months after the 2nd COVID-19 vaccination, but were restored upon the 3rd vaccination. The COVID-19 vaccine-induced antibodies mainly targeted novel, non-cross-reactive S1 epitopes of the viral spike protein, while cross-reactive S2 epitopes were less immunogenic. Booster vaccination not only strongly enhanced neutralizing antibodies against an original SARS-CoV-2 strain, but also induced neutralizing antibodies against the Omicron BA.2 variant. We observed a 100% plasma antibody prevalence against the S1 subunits of HCoVs, which was not affected by vaccination.

Discussion

Overall, by complementing classical serology with a functional evaluation of plasmablasts and memory B cells we provide new insights into the specificity of COVID-19 vaccine-induced antibody and B cell responses.

Epidemiological characteristics and antibody kinetics of elderly population with booster vaccination following both Omicron BA.5 and XBB waves in China

After the termination of zero-COVID-19 policy, the populace in China has experienced both Omicron BA.5 and XBB waves. Considering the poor antibody responses and severe outcomes observed among the elderly following infection, we conducted a longitudinal investigation to examine the epidemiological characteristics and antibody kinetics among 107 boosted elderly participants following the Omicron BA.5 and XBB waves. We observed that 96 participants (89.7%) were infected with Omicron BA.5, while 59 (55.1%) participants were infected with Omicron XBB. Notably, 52 participants (48.6%) experienced dual infections of both Omicron BA.5 and XBB. The proportion of symptomatic cases appeared to decrease following the XBB wave (18.6%) compared to that after the BA.5 wave (59.3%). Omicron BA.5 breakthrough infection induced lower neutralizing antibody titers against XBB.1.5, BA.2.86, and JN.1, while reinfection with Omicron XBB broadened the antibody responses against all measured Omicron subvariants and may alleviate the wild type-vaccination induced immune imprinting. Boosted vaccination type and comorbidities were the significant factors associated with antibody responses. Updated vaccines based on emerging severe acute respiratory syndrome coronavirus 2 variants are needed to control the Coronavirus Disease 2019 pandemic in the elderly.

Lessons from COVID-19 Pandemic: A Successful Policy and Practice by Pasteur Institute of Iran

The present study aims to provide an insight to the comprehensive efforts of Pasteur Institute of Iran (PII) regarding COVID-19 management, research, achievements, and vaccine production, though there are many challenges. The relevant literature review was investigated through national and international database and also reports from the related research departments. Six strategies were taken by PII to manage the pandemic of COVID-19. While this pandemic has been hopefully controlled, SARS-CoV-2 could still be a potential threat. Therefore, COVID-19 data management and updated studies, as well as long-term safety and efficacy of the SARS-CoV-2 vaccines are still on the agenda.

Evaluation of PastoCovac plus vaccine as a booster dose on vaccinated individuals with inactivated COVID-19 vaccine

COVID-19 pandemic has been managed through global vaccination programs. However, the antibody waning in various types of vaccines came to notice. Hereby, PastoCovac Plus as a protein subunit vaccine was investigated in immunized health care workers by COVAXIN (BBV152). The booster vaccine was recommended at least three months post the second dose of COVAXIN. Sera collection was done before and after each injection. SARS-CoV-2 PCR test was done monthly to detect any asymptomatic and symptomatic vaccine breakthrough. 47.9 and 24.3% of the participants were seronegative for anti-N and anti-S antibodies three months after the second dose of COVAXIN, respectively. On average, fold-rises of 70, 93, 8 and mean-rises of 23.32, 892.4, 5.59 were recorded regarding neutralizing antibody, quantitative and semi-quantitative anti-Spike antibody, respectively. Anti-Spike and neutralizing antibodies seroconversion was seen 59.3% and 45.7%, respectively. The vaccine breakthrough assessment showed that all the isolated samples belonged to SARS-CoV-2 Delta variant. PastoCovac Plus boosting is strongly recommended in combination with inactivated vaccine platforms against SARS-CoV-2.