Covaxin: An overview of its immunogenicity and safety trials in India

Co-Delivery of Novel Synthetic TLR4 and TLR7/8 Ligands Adsorbed to Aluminum Salts Promotes Th1-Mediated Immunity against Poorly Immunogenic SARS-CoV-2 RBD

Despite the availability of effective vaccines against COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread worldwide, pressing the need for new vaccines with improved breadth and durability. We developed an adjuvanted subunit vaccine against SARS-CoV-2 using the recombinant receptor-binding domain (RBD) of spikes with synthetic adjuvants targeting TLR7/8 (INI-4001) and TLR4 (INI-2002), co-delivered with aluminum hydroxide (AH) or aluminum phosphate (AP). The formulations were characterized for the quantities of RBD, INI-4001, and INI-2002 adsorbed onto the respective aluminum salts. Results indicated that at pH 6, the uncharged RBD (5.73 ± 4.2 mV) did not efficiently adsorb to the positively charged AH (22.68 ± 7.01 mV), whereas it adsorbed efficiently to the negatively charged AP (-31.87 ± 0.33 mV). Alternatively, pre-adsorption of the TLR ligands to AH converted it to a negatively charged particle, allowing for the efficient adsorption of RBD. RBD could also be directly adsorbed to AH at a pH of 8.1, which changed the charge of the RBD to negative. INI-4001 and INI-2002 efficiently to AH. Following vaccination in C57BL/6 mice, both aluminum salts promoted Th2-mediated immunity when used as the sole adjuvant. Co-delivery with TLR4 and/or TLR7/8 ligands efficiently promoted a switch to Th1-mediated immunity instead. Measurements of viral neutralization by serum antibodies demonstrated that the addition of TLR ligands to alum also greatly improved the neutralizing antibody response. These results indicate that the addition of a TLR7/8 and/or TLR4 agonist to a subunit vaccine containing RBD antigen and alum is a promising strategy for driving a Th1 response and neutralizing antibody titers targeting SARS-CoV-2.

Non-Invasive Vaccines: Challenges in Formulation and Vaccine Adjuvants

Given the limitations of conventional invasive vaccines, such as the requirement for a cold chain system and trained personnel, needle-based injuries, and limited immunogenicity, non-invasive vaccines have gained significant attention. Although numerous approaches for formulating and administrating non-invasive vaccines have emerged, each of them faces its own challenges associated with vaccine bioavailability, toxicity, and other issues. To overcome such limitations, researchers have created novel supplementary materials and delivery systems. The goal of this review article is to provide vaccine formulation researchers with the most up-to-date information on vaccine formulation and the immunological mechanisms available, to identify the technical challenges associated with the commercialization of non-invasive vaccines, and to guide future research and development efforts.

Nanomaterials to combat SARS-CoV-2: Strategies to prevent, diagnose and treat COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the associated coronavirus disease 2019 (COVID-19), which severely affect the respiratory system and several organs and tissues, and may lead to death, have shown how science can respond when challenged by a global emergency, offering as a response a myriad of rapid technological developments. Development of vaccines at lightning speed is one of them. SARS-CoV-2 outbreaks have stressed healthcare systems, questioning patients care by using standard non-adapted therapies and diagnostic tools. In this scenario, nanotechnology has offered new tools, techniques and opportunities for prevention, for rapid, accurate and sensitive diagnosis and treatment of COVID-19. In this review, we focus on the nanotechnological applications and nano-based materials (i.e., personal protective equipment) to combat SARS-CoV-2 transmission, infection, organ damage and for the development of new tools for virosurveillance, diagnose and immune protection by mRNA and other nano-based vaccines. All the nano-based developed tools have allowed a historical, unprecedented, real time epidemiological surveillance and diagnosis of SARS-CoV-2 infection, at community and international levels. The nano-based technology has help to predict and detect how this Sarbecovirus is mutating and the severity of the associated COVID-19 disease, thereby assisting the administration and public health services to make decisions and measures for preparedness against the emerging variants of SARS-CoV-2 and severe or lethal COVID-19.

The Vaccine World of COVID-19: India’s Contribution

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) eruption has left not only illness and mortality in its wake, but also an overwhelming threat to health policy, human regality, food security, and struggle worldwide. The accessibility and potential distribution of a protective and successful vaccination to communities throughout the world are being considered now not just, as a potential of overcoming these hurdles, but also as an example of human perseverance in the face of catastrophe. A vaccine is the only tool that can efficaciously deal with the COVID-19 catastrophe. Currently, more than 47 vaccines are permitted for emergency use in distinct parts of the world. India will play a significant role in the development of the high-priced Moderna shots and Pfizer Inc, therefore assisting in the immunization of a large portion of the world. Moreover, many of the internationally researched and developed vaccine laboratories seek manufacturing in Indian firms and companies for efficient and low-cost production of vaccines intending to provide to the world, hence, making India, a major role player during these pandemic times. This review highlights the Indian contribution to the globe for COVID-19 management.

Assessment of Clinical Profile and Treatment Outcome in Vaccinated and Unvaccinated SARS-CoV-2 Infected Patients

Vaccines against severe acute respiratory syndrome-corona virus-2 (SARS-CoV-2) infection, which causes coronavirus disease–19 (COVID-19) in humans, have been developed and are being tested for safety and efficacy. We conducted the cross-sectional prospective cohort study on 820 patients who were positive for SARS-CoV-2 and were admitted to Princess Krishnajammanni trauma care centre (PKTCC), Mysore, which was converted to a designated COVID hospital between April 2021 to July 2021. After obtaining the informed consent, RT-PCR report, vaccination certificate and patient history, patients were classified according to their vaccination status. Results from the study showed decreases in serum ferritin levels, clinical symptoms, improvement in oxygen saturation, early recovery in patients having diabetes and hypertension, and a substantial reduction in the overall duration of hospital stay in vaccinated patients compared to unvaccinated patients. Further, fully vaccinated patients showed better outcomes compared to single dose vaccinated and nonvaccinated patients. Taken together, our findings reaffirm the vaccine’s effectiveness in reducing case fatality and promoting faster recovery compared to nonvaccinated patients. Efforts to increase the number of immunized subjects in the community help to achieve herd immunity and offer protection against the severity of COVID-19 and associated complications while minimizing the public health and economic burden.

An overview on inactivated and live-attenuated SARS-CoV-2 vaccines

After about 2 years since severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), first infections were detected in Wuhan city of China in December 2019, which was followed by a worldwide pandemic with a record of 5.41 million deaths. Due to urgent need for the development of a safe and effective vaccine for coronavirus disease 2019 (COVID‐19), attempts for producing efficient vaccines are inexhaustibly continuing. According to a report by the World Health Organization (WHO) on COVID‐19 vaccine tracker and landscape, there are 149 vaccine candidates all over the world. Inactivated SARS‐CoV‐2 vaccines as a conventional vaccine platform consist of whole virus particles grown in cell culture and inactivated by chemicals. Because of benefits such as antigenic similarity to real virion inducing humoral and cellular immune responses and ease for transport and storage, these vaccines, including the vaccines produced by Bharat Biotech, Sinopharm, and Sinovac, are in use at large scales. In this study, we have a review on inactivated SARS‐CoV‐2 vaccines that are passing their phase 3 and 4 clinical trials, population which was included in the trials, vaccine producers, the efficiency, adverse effects, and components of vaccines, and other vaccine features.

A Comprehensive Review on Various Aspects of SARS-CoV-2 (COVID-19) Vaccines

This is a comprehensive review based on the published papers in the field of COVID-19 vaccines and vaccination. Many efforts have been made to develop vaccines to combat this pandemic. Since December 2020, more than 200 vaccines have been tested in various research stages and in clinical trials on humans, of which eight vaccines reached phase four clinical trials in humans and approved by FDA and EUA. After the Pfizer-BioNTech vaccine that had the highest efficacy (95%), the efficacy of the other vaccines are as follows: Moderna 94.5%, Sputnik V 91%, Novavax 89.7%, Sinopharm 79.3%, Oxford/AstraZenaca 70.4%, Johnson and Johnson 66.9%, and Sinovac 50.7%. At present, protein-based vaccines, with 35% of all available COVID-19 vaccines, are the most common technique in the vaccine production, and then there are vaccines of non-replicating viral vector (13.3%), mRNA1 (12.1%), DNA (10.2%), replicating viral vector (9.8%), and inactivated vaccines (8.2%). The most frequently recognized adverse effects within 7 days of each vaccine dose involved fever, fatigue, headache, chill, and myalgia. The mRNA-based vaccines were associated with a higher occurrence of local side effects (78.3 vs. 70.4%; Sig. = 0.064), whereas the viral vector-based vaccine was associated with a higher prevalence of systemic side effects (87.2 vs. 61%; Sig. < 0.001). Based on the evidence and articles in the field of vaccination, AstraZeneca-Oxford and Sinopharm vaccines reported the highest and lowest side effects, respectively. Because of being emerging, pathogenicity, and high infectivity of COVID-19, vaccination against the disease to prevent its incident rate and decrease the prevalence rate is recommended immediately. Being informed of various aspects of the existing vaccines such as efficacy, effectiveness, safety, etc.can accelerate to make effective and useful choices and consequently have a vaccinated community against the epidemic.