Safety, tolerability and immunogenicity of Biological E's CORBEVAX™ vaccine in children and adolescents: A prospective, randomised, double-blind, placebo controlled, phase-2/3 study

Phase 1 trial of an investigational Tdap booster vaccine with CpG 1018 adjuvant compared with Boostrix in healthy adults and adolescents

This phase 1 trial assessed the safety and immunogenicity of an investigational tetanus/diphtheria/acellular pertussis vaccine combined with CpG 1018 adjuvant 1500 μg (Tdap-1018 1500 μg) or 3000 μg (Tdap-1018 3000 μg) in adults and adolescents. In this randomized, active-controlled, multicenter, dose-escalation trial, healthy participants aged 10 to 22 years received 1 dose of Tdap-1018 1500 μg, Tdap-1018 3000 μg, or Boostrix. Geometric mean concentrations (GMCs) and booster response rates (BRRs) for antibodies against pertussis (pertussis toxin, filamentous hemagglutinin, pertactin), tetanus, and diphtheria antigens, and neutralizing antibodies against pertussis toxin were assessed 4 weeks after vaccination. Safety and tolerability were assessed for solicited post-injection reactions within 7 days after vaccination and unsolicited adverse events up to 12 weeks after vaccination. Of 117 enrolled participants, 80 adults (92%) and 30 adolescents (100%) completed the study. Both Tdap-1018 formulations were generally well tolerated, with no vaccine-related serious adverse events. Frequency and severity in post-injection reactions after Tdap-1018 administration were similar to Boostrix except for higher proportions of moderate pain for Tdap-1018. In adults at week 4, ratio of GMCs and BRRs for all antigens in the 3000-μg group were similar to or higher than Boostrix, with significantly higher GMC ratios for anti-pertussis toxin (2.1 [1.5-3.0]) and anti-tetanus (1.8 [1.1-2.9]) and significantly higher BRRs for anti-pertussis toxin (difference [95% CI]: 34.5% [13.4-54.6]), anti-pertactin (19.2% [4.4-38.1]), and anti-tetanus (30.0% [3.6-52.7]) antibodies. For adolescents, in the 3000-μg group, ratio of GMCs and BRRs were similar to or higher than Boostrix for all antigens. Both Tdap-1018 formulations showed acceptable safety and tolerability profiles. Tdap-1018 3000 μg induced similar or higher immune responses than Boostrix. ACTRN12620001177943 (Australian New Zealand Clinical Trials Registry; https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=ACTRN12620001177943p).

Vaccine Science Diplomacy and "The Phenomenon of Man"

The central tenets of international scientific collaborations leading to the development, testing, and the equitable distribution vaccines to combat poliomyelitis, smallpox, COVID-19, and other devasting infections, first accelerated in the mid-twentieth century. The genesis of vaccine science diplomacy also coincides with the publication of Le Phénomène Humain (The Phenomenon of Man) shortly after the death of its author, the French Jesuit priest and scientist, Dr. Teilhard de Jardin. Several tenets of Teilhard's posthumous essay, including our collective consciousness, and the "conjugated faces" of science and religion, are relevant to a modern vaccine diplomacy framework, even if Teilhard may not have specifically addressed vaccines in his writings. This could also include the potential for arriving at an "omega point" through international scientific collaboration and joint vaccine development, while simultaneously avoiding the destructive forces of anti-vaccine or anti-science activism. Collaborations between the Vatican, Catholic research universities and institutions; and leaders of the Catholic-majority nations in Africa, Asia, and Latin America in an integrated framework might accelerate these activities as they apply to both pandemic threats and neglected diseases of poverty.

A Journey in Science: Molecular vaccines for global child health in troubled times of anti-science

My scientific life in translational medicine runs in two parallel, yet often converging paths. The first, is four-decade-long commitment to develop new vaccines for parasitic and neglected tropical diseases, as well as pandemic threats. This includes a vaccine for human hookworm infection that I began as an MD-PhD student in New York City in the 1980s, and a new low-cost COVID vaccine that reached almost 100 million people in low- and middle-income countries. Alongside this life in scientific research, is one in public engagement for vaccine and neglected disease diplomacy to ensure that people who live in extreme poverty can benefit from access to biomedical innovations. A troubling element has been the daunting task of countering rising antivaccine activism, which threatens to undermine our global vaccine ecosystem. Yet, this activity may turn out to become just as important for saving lives as developing new vaccines.

A quest for universal anti-SARS-CoV-2 T cell assay: systematic review, meta-analysis, and experimental validation

Measuring SARS-CoV-2-specific T cell responses is crucial to understanding an individual's immunity to COVID-19. However, high inter- and intra-assay variability make it difficult to define T cells as a correlate of protection against COVID-19. To address this, we performed systematic review and meta-analysis of 495 datasets from 94 original articles evaluating SARS-CoV-2-specific T cell responses using three assays - Activation Induced Marker (AIM), Intracellular Cytokine Staining (ICS), and Enzyme-Linked Immunospot (ELISPOT), and defined each assay's quantitative range. We validated these ranges using samples from 193 SARS-CoV-2-exposed individuals. Although IFNγ ELISPOT was the preferred assay, our experimental validation suggested that it under-represented the SARS-CoV-2-specific T cell repertoire. Our data indicate that a combination of AIM and ICS or FluoroSpot assay would better represent the frequency, polyfunctionality, and compartmentalization of the antigen-specific T cell responses. Taken together, our results contribute to defining the ranges of antigen-specific T cell assays and propose a choice of assay that can be employed to better understand the cellular immune response against viral diseases.

An Outline of the Immunogenic Potential of Progressing SARSCoV- 2 Vaccine Technologies among Children and Adolescents

BACKGROUND

SARS-CoV-2, a highly dynamic beta-coronavirus, can afflict all age groups. Notably, over 16100 mortalities have been recorded among children as yet. In this regard, many vaccine projects are operational to assess immuno-potency among young cohorts. A bulk of reports have evidenced the efficacy of these immunization technologies in the elderly population, though the impact is yet to be determined among children.

OBJECTIVES

This review is envisioned to outline the current efficacy of contributing vaccine technologies and examine the dose-dependent impact of immunization regimens in lowering the risks of SARS-CoV-2 infections among children and adolescents. Furthermore, the current review exclusively estimated the vaccine impact at current doses.

METHODS

A total of 52 research papers extracted from PubMed, Pubmed Central, Science Direct, Research Gate, Google Scholar and Semantic Scholar were screened along with an emphasis on patents. Inclusion criteria involved all published reports directly or indirectly linked to the contributing vaccine candidates that are operational among the young cohort. Unrelated research papers were excluded from the study. Key search terminologies included information on vaccine identifiers, such as name, type and clinical trial ID, and successively restricted to children and adolscents age groups.

RESULTS

Several vaccine designs, such as mRNA-based vaccinations, viral vector vaccines, DNA vaccines, inactivated vaccines, recombinant vaccines, and protein-based immunizations, are being examined at various stages of clinical trials to gauge the effects on children and adolescents. With reference to the published reports, the mRNA 1273 (1610 GMT; 6-10 yrs, 1401 GMT; 12-15 yrs), BNT162b2 (1407 GMT; 6 months- <2 yrs, 1535 GMT; 2-4 yrs, 4583 GMT; 5-11 yrs, 1239.5 GMT; 12-15 yrs) and Ad5 nCoV (1037.5 GMT; 6-17 yrs) offered relatively high neutralization titers with sharp seroconversion rates compared to MVC-COV1901 (648.5 GMT; 12-17 yrs) and ZyCoV-D (133.49 GMT; 12-17 yrs), which produced modest immune responses.

CONCLUSION

Currently, the WHO is analyzing emerging evidence to issue an emergency use list of vaccines for vaccinating children and adolescents.

Structure-based design of oligomeric receptor-binding domain (RBD) recombinant proteins as potent vaccine candidates against SARS-CoV-2

The receptor-binding domain (RBD) of SARS-CoV-2 S protein is proved to be the major target of neutralizing antibodies. However, on the S protein, only a portion of epitopes in RBD can be effectively displayed with dynamic changes in spatial conformations. Using RBD fragment as antigen can better expose the neutralizing epitopes, but the immunogenicity of RBD monomer is suboptimal. Multimeric display of RBD molecules is a feasible strategy to optimize RBD-based vaccines. In this study, RBD single-chain dimer derived from Wuhan-Hu-1 was fused with a trimerization motif, and a cysteine was also introduced at the C-terminus. The resultant recombinant protein 2RBDpLC was expressed in Sf9 cells using a baculovirus expression system. Reducing/non-reducing PAGE, size-exclusion chromatography and in silico structure prediction indicated that 2RBDpLC polymerized and possibly formed RBD dodecamers through trimerization motif and intermolecular disulfide bonds. In mice, 2RBDpLC induced higher levels of RBD-specific and neutralizing antibody responses than RBD dimer, RBD trimer and prefusion-stabilized S protein (S2P). In addition, cross-neutralizing antibodies against Delta and Omicron VOC were also detected in the immune sera. Our results demonstrate that 2RBDpLC is a promising vaccine candidate, and the method of constructing dodecamers may be an effective strategy for designing RBD-based vaccines.

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.

Healthcare provider perspectives on COVID-19 vaccination for children in India

BACKGROUND

The rapid development and deployment of effective COVID-19 vaccines have been critical to halt the spread of the pandemic. India started vaccinating children in early 2022, however, vaccine uptake has been suboptimal.

METHODS

Between September and November 2022, we conducted an online survey that was disseminated to eligible participants via email, text messages and social media platforms across India. The survey aimed to gather the perspectives of Indian healthcare providers regarding key factors related to the rollout of paediatric COVID-19 vaccines. Descriptive statistics were used to analyse participant demographics and responses on knowledge about paediatric COVID-19 vaccines, perceived risks and benefits, and vaccine rollout strategies.

RESULTS

The survey yielded 805 respondents from 23 Indian states; 63.5% were men, 97.3% were paediatricians, median age was 44 years (IQR 25-81). Eighty-one per cent and 65.2% respondents had heard about the most common paediatric COVID-19 vaccines in India, Covaxin and Corbevax, but only 52.9%, 53.7% and 62.1% felt adequately informed about their safety, efficacy and vaccination schedules, respectively. Thirty per cent of respondents were unaware of vaccination guidelines. Eighty-five per cent of respondents felt that vaccines would reduce the incidence of severe disease, hospitalisation and deaths, and 60.6% felt children with comorbidities should be prioritised for vaccination. Perceived supply side barriers included lack of enforcement of guidelines (45.2%) and adverse effects following immunisation monitoring systems (37.6%), and on the demand side, parental vaccine hesitancy (64.4%). Eighty-one per cent believed that school-based vaccination strategies would be highly effective in increasing uptake.

CONCLUSIONS

Most respondents were in support of the COVID-19 paediatric vaccination, although just over half did not feel adequately informed. Concerns about vaccine hesitancy among caregivers were the leading reported barrier. Targeted interventions are needed to provide adequate knowledge support to healthcare providers and evidence-based public health messaging to reduce vaccine hesitancy among caregivers.

COVID-19 Vaccines over Three Years after the Outbreak of the COVID-19 Epidemic

The outbreak of COVID-19 started in December 2019 and spread rapidly all over the world. It became clear that the development of an effective vaccine was the only way to stop the pandemic. It was the first time in the history of infectious diseases that the process of the development of a new vaccine was conducted on such a large scale and accelerated so rapidly. At the end of 2020, the first COVID-19 vaccines were approved for marketing. At the end of March 2023, over three years after the outbreak of the COVID-19 pandemic, 199 vaccines were in pre-clinical development and 183 in clinical development. The candidate vaccines in the clinical phase are based on the following platforms: protein subunit, DNA, RNA, non-replication viral vector, replicating viral vector, inactivated virus, virus-like particles, live attenuated virus, replicating viral vector combined with an antigen-presenting cell, non-replication viral vector combined with an antigen-presenting cell, and bacterial antigen-spore expression vector. Some of the new vaccine platforms have been approved for the first time for human application. This review presents COVID-19 vaccines currently available in the world, procedures for assurance of the quality and safety of the vaccines, the vaccinated population, as well as future perspectives for the new vaccine platforms in drug and therapy development for infectious and non-infectious diseases.

Safety and Immunogenicity of SARS-CoV-2 Recombinant Spike Protein Vaccine in Children and Adolescents in India: A Phase 2-3 Randomized Clinical Trial

Importance

The recombinant COVID-19 vaccine NVX-CoV2373 has demonstrated efficacy of approximately 90% in adults; however, its safety and efficacy in children is unknown.

Objective

To assess the noninferiority of SII-NVX-CoV2373 in children and adolescents compared to adults and to evaluate its safety in comparison with placebo.

Design, Setting, and Participants

This phase 2-3 observer-blind randomized clinical trial was conducted in 2 cohorts, children (aged 2 to 11 years) and adolescents (aged 12 to 17 years) between August 2021 and August 2022. Participants were randomized 3:1 to SII-NVX-CoV2373 or placebo and monitored for 179 days. The participants, study team, and laboratory staff were blinded. This was a multicenter study conducted across 10 tertiary care hospitals in India. Exclusion criteria included previous COVID-19 infection or vaccination, immunocompromised condition, and immunosuppressive medications.

Interventions

Two doses of 0.5-mL SII-NVX-CoV2373 or placebo were administered intramuscularly on days 1 and 22.

Main Outcomes and Measures

Primary outcomes were geometric mean titer ratio of both anti-spike (anti-S) IgG and neutralizing antibodies (NAbs) between both pediatric age groups to that of adults on day 36. Noninferiority was concluded if the lower bound of 95% CI of this ratio was greater than 0.67 for each age group. Both the antibodies were assessed for the index strain and for selected variants at various time points. Solicited adverse events (AEs) were recorded for 7 days after each vaccination, unsolicited AEs were recorded for 35 days, and serious AEs and AEs of special interest were recorded for 179 days.

Results

A total of 460 children in each age cohort were randomized to receive vaccine or placebo. The mean (SD) age was 6.7 (2.7) years in the child cohort and 14.3 (1.6) years in the adolescent cohort; 231 participants (50.2%) in the child cohort and 218 in the adolescent cohort (47.4%) were female. Both anti-S IgG and NAb titers were markedly higher in the SII-NVX-CoV2373 group than in the placebo group on both day 36 and day 180. The geometric mean titer ratios compared to those in adults were 1.20 (95% CI, 1.08-1.34) and 1.52 (95% CI, 1.38-1.67) for anti-S IgG in adolescents and children, respectively; while for NAbs, they were 1.33 (95% CI, 1.17-1.50) and 1.93 (95% CI, 1.70-2.18) in adolescents and children, respectively, indicating noninferiority. SII-NVX-CoV2373 also showed immune responses against variants studied. Injection site reactions, fever, headache, malaise, and fatigue were common solicited AEs. There were no AEs of special interest and no causally related serious AEs.

Conclusions and Relevance

SII-NVX-CoV2373 was safe and well tolerated in children and adolescents in this study. The vaccine was highly immunogenic and may be used in pediatric vaccination against COVID-19.

Trial Registration

Clinical Trials Registry of India Identifier: CTRI/2021/02/031554.

COVID-19 vaccines and the pandemic: lessons learnt for other neglected diseases and future threats

Through the experiences gained by accelerating new vaccines for both Ebola virus infection and COVID-19 in a public health emergency, vaccine development has benefited from a 'multiple shots on goal' approach to new vaccine targets. This approach embraces simultaneous development of candidates with differing technologies, including, when feasible, vesicular stomatitis virus or adenovirus vectors, messenger RNA (mRNA), whole inactivated virus, nanoparticle and recombinant protein technologies, which led to multiple effective COVID-19 vaccines. The challenge of COVID-19 vaccine inequity, as COVID-19 spread globally, created a situation where cutting-edge mRNA technologies were preferentially supplied by multinational pharmaceutical companies to high-income countries while low and middle-income countries (LMICs) were pushed to the back of the queue and relied more heavily on adenoviral vector, inactivated virus and recombinant protein vaccines. To prevent this from occurring in future pandemics, it is essential to expand the scale-up capacity for both traditional and new vaccine technologies at individual or simultaneous hubs in LMICs. In parallel, a process of tech transfer of new technologies to LMIC producers needs to be facilitated and funded, while building LMIC national regulatory capacity, with the aim of several reaching 'stringent regulator' status. Access to doses is an essential start but is not sufficient, as healthcare infrastructure for vaccination and combating dangerous antivaccine programmes both require support. Finally, there is urgency to establish an international framework through a United Nations Pandemic Treaty to promote, support and harmonise a more robust, coordinated and effective global response.

Nanoalum Formulations Containing Aluminum Hydroxide and CpG 1018TM Adjuvants: The Effect on Stability and Immunogenicity of a Recombinant SARS-CoV-2 RBD Antigen

Aluminum-salt vaccine adjuvants (alum) are commercially available as micron-sized particles with varying chemical composition and crystallinity. There are reports of enhanced adjuvanticity when the alum's particle size is reduced to the nanometer range. Previously, we demonstrated that a recombinant receptor-binding domain (RBD)-based COVID-19 vaccine candidate (RBD-J; RBD-L452K-F490W) formulated with aluminum hydroxide (Alhydrogel^®; AH) and CpG 1018™ (CpG) adjuvants induced potent neutralizing antibody responses in mice yet displayed instability during storage. In this work, we evaluated whether sonication of AH to the nanometer size range (nanoAH) could further enhance immunogenicity or improve storage stability of the above formulation. The addition of CpG to nanoAH (at mouse doses), however, caused re-agglomeration of nanoAH. AH-CpG interactions were evaluated by Langmuir binding isotherms and zeta potential measurements, and stabilized nanoAH + CpG formulations of RBD-J were then designed by (1) optimizing CpG:Aluminum dose ratios or (2) adding a small-molecule polyanion (phytic acid, PA). Compared with the micron-sized AH + CpG formulation, the two stabilized nanoAH + CpG formulations of RBD-J demonstrated no enhancement in SARS-CoV-2 pseudovirus neutralizing titers in mice, but the PA-containing nanoAH + CpG formulation showed improved RBD-J storage stability trends (at 4, 25, and 37 °C). The formulation protocols presented herein can be employed to evaluate the potential benefits of the nanoAH + CpG adjuvant combination with other vaccine antigens in different animal models.

Children's SARS-CoV-2 Infection and Their Vaccination

SARS-CoV-2, a novel coronavirus, causes respiratory tract infections and other complications in affected individuals, and has resulted in numerous deaths worldwide. The unprecedented pace of its transmission worldwide, and the resultant heavy burden on healthcare systems everywhere, prompted efforts to have effective therapeutic strategies and vaccination candidates available to the global population. While aged and immunocompromised individuals form a high-risk group for COVID-19 and have severe disease outcome, the rate of infections among children has also increased with the emergence of the Omicron variant. In addition, recent reports of threatening SARS-CoV-2-associated complications in children have brought to the forefront an urgent necessity for vaccination. In this article, we discuss the current scenario of SARS-CoV-2 infections in children with a special focus on the differences in their immune system response as compared to adults. Further, we describe the various available COVID-19 vaccines, including the recent bivalent vaccines for children, in detail, intending to increase willingness for their acceptance.

COVID-19 Vaccination in Pediatrics: Was It Valuable and Successful?

BACKGROUND

The mass vaccination of children against coronavirus 2019 disease (COVID-19) has been frequently debated. The risk-benefit assessment of COVID-19 vaccination versus infection in children has also been debated.

AIM

This systematic review looked for answers to the question "was the vaccination of our children valuable and successful?".

METHODS

The search strategy of different articles in the literature was based on medical subject headings. Screening and selection were based on inclusion/exclusion criteria.

RESULTS AND DISCUSSION

The search results revealed that the majority of the reported adverse events after COVID-19 vaccination in pediatrics were mild to moderate, with few being severe. Injection site discomfort, fever, headache, cough, lethargy, and muscular aches and pains were the most prevalent side effects. Few clinical studies recorded significant side effects, although the majority of these adverse events had nothing to do with vaccination. In terms of efficacy, COVID-19 disease protection was achieved in 90-95% of cases for mRNA vaccines, in 50-80% of cases for inactivated vaccines, and in 58-92% of cases for adenoviral-based vaccines in children and adolescents.

CONCLUSIONS

Based on available data, COVID-19 immunizations appear to be safe for children and adolescents. Furthermore, multiple studies have proven that different types of vaccines can provide excellent protection against COVID-19 in pediatric populations. The efficacy of vaccines against new SARS-CoV-2 variants and the reduction in vaccine-related long-term adverse events are crucial for risk-benefit and cost-effectiveness assessments; therefore, additional safety studies are required to confirm the long-term safety and effectiveness of vaccinations in children.

Safety, Efficacy, and Immunogenicity of Varying Types of COVID-19 Vaccines in Children Younger Than 18 Years: An Update of Systematic Review and Meta-Analysis

Vaccination is one of the most effective measures for children as the epidemic progresses. However, there is a significant research gap in the meta-analysis of the COVID-19 vaccines for children younger than 18 years. This study is a comprehensive review of different COVID-19 vaccines. Published articles were retrieved from PubMed, Embase, and the Cochrane Library. Twelve randomized controlled trials (RCTs) of COVID-19 vaccines were included in the review until 21 October 2022. Most local and systemic adverse reactions were predominantly mild to moderate in severity and disappeared quickly after different types of vaccines. The subunit vaccine had the highest safety. The significant risk was lower in the subunit vaccine group after the initial (RR 1.66, 95% CI 1.26-2.17, p = 0.0003) and booster vaccination (RR 1.40, 95% CI 1.02-1.92, p = 0.04). Younger children had a more outstanding safety profile in the mRNA and inactivated vaccine groups. The humoral immune response was proportional to the number of doses in the inactivated and the adenovirus vaccine groups, and the strength of immunogenicity was negatively correlated with age in the inactivated vaccine. The mRNA and the subunit vaccines provided satisfactory prevention against COVID-19, especially seven days after the booster dose. However, more research and longer-term follow-up are needed to assess the duration of immune responses, efficacy, and safety.