COVID-19 Immunity Research Articles

Altered COVID-19 Immunity in Children With Asthma by Atopic Status.

Altered COVID-19 Immunity in Children With Asthma by Atopic Status.

Understanding the Challenges of Advocacy Communication, Social Mobilization, and Operationalization for COVID-19 and Routine Immunization in Nigeria.

The primary goal of program communication in public health is to influence behaviors. It also aims to raise awareness and ultimately improve health outcomes. Under the umbrella of program communication exist three interconnected, interrelated, and mutually supportive communication aspects: advocacy, communication, and social mobilization (ACSM). While advocacy involves promoting political dedication and holding authorities accountable for fulfilling commitments and achieving success, social mobilization brings together various sectors and individuals to raise awareness and demand for a specific program. This study aimed to understand the operationalization and challenges of ACSM activities among health workers addressing COVID-19 and routine immunization in Nigeria. The study used a qualitative study design. In-depth interviews were conducted among health workers in the ACSM unit of the state's primary health care system, using a two-tier approach. The recorded interviews were transcribed in Microsoft Word format by professional transcribers and coded using Dedoose. A total of 38 health care workers across six states were selected to participate in this study. Our study found that ACSM coordination structures existed across the six states. Routine ACSM activities were either funded by the government or local development partners implementing programs. Lack of technological devices, unavailability of funds, unavailability of data tools, and lack of technological skills are major barriers to ACSM operationalization. This study highlighted the critical role of government and agency funding in sustaining ACSM activities. However, barriers that hinder the effective operationalization of ACSM efforts remain. Therefore, the results support the need for strategic investment in technology, staff capacity building, and appropriate resource allocation to overcome these barriers.

Experiences and perceptions of migrant populations in South Africa on COVID-19 immunization: an interpretative phenomenological analysis

IntroductionMigrant populations (asylum seekers, permit holders, refugees, and undocumented migrants) living in South Africa face various individual, social, and physical circumstances that underpin their decisions, motivation, and ability to receive the COVID-19 vaccine. We conducted a qualitative study to explore the experiences and perceptions of migrant populations in South Africa on COVID-19 vaccines to inform recommendations for improved COVID-19 immunization.MethodsWe conducted an Interpretative Phenomenological Analysis (IPA) with 20 asylum seekers, permit holders, refugees, and undocumented migrants living in South Africa. We applied a maximum variation purposive sampling approach to capture all three categories of migrants in South Africa. Semi-structured interviews were conducted and recorded electronically with consent and permission from the study participants. The recordings were transcribed and analyzed thematically following the IPA using Atlas.ti version 9.ResultsFour major reflective themes emanated from the data analysis. (1) While some migrants perceived being excluded from the South African national immunization program at the level of advertisement and felt discriminated against at the immunization centers, others felt included in the program at all levels. (2) Skepticism, myths, and conspiracy theories around the origin of SARS-CoV-2 and the COVID-19 vaccine are pervasive among migrant populations in South Africa. (3) There is a continuum of COVID-19 vaccine acceptance/hesitancy ranging from being vaccinated through waiting for the chance to be vaccinated to refusal. (4) Accepting the vaccine or being hesitant follows the beliefs of the participant, knowledge of the vaccine’s benefits, and lessons learned from others already vaccinated.ConclusionCOVID-19 vaccine inclusiveness, awareness, and uptake should be enhanced through migrant-aware policies and actions such as community mobilization, healthcare professional training, and mass media campaigns.

COVID-19 Immunization for Adolescents: What does the Scientific Evidence Tell us?

COVID-19 Immunization for Adolescents: What does the Scientific Evidence Tell us?

Traceability for strengthening supply chain systems and enhancing real-time visibility: Focus of NAFDAC on advancing vaccine traceability in Nigeria

This study explores the successful implementation of activities aimed at scaling traceability for COVID-19 and routine immunization (RI) vaccines to the local government area and selected healthcare facilities in Nigeria, funded by the Bill and Melinda Gates Foundation. The study was executed by the National Agency for Food and Drug Administration and Control (NAFDAC) and sought to enhance supply chain systems by deploying advanced traceability mechanisms and ensuring real-time stock visibility. The article discusses the accomplishments, challenges, and regulatory framework of NAFDAC, emphasizing GS1 technology-driven traceability, and presents the results of the field scanning activities conducted in July 2023. The approach involved a phased public sector pilot, showcasing the feasibility and challenges of tracking vaccine movement through the supply chain. The result shows the detection of 43 unique products across 1022 facilities from a total of 110,113 scans, offering valuable insights into vaccine distributions. The strategic goals of the project aligned with developing safety surveillance systems in low- and middle-income countries (LMICs) to facilitate patient access to global health products. Similarly, significant improvement in traceability through automated data capture (barcode scanning) and expanded coverage for COVID-19 and selected RI vaccines in Nigeria was found. Against this background, the information derived from this report will build confidence in patients regarding vaccine authenticity, establish a transparent and robust supply chain, and foster pharmacovigilance capability through integration with the track-and-trace systems. Thus, the study provides invaluable insights and opportunities for global health practitioners, policymakers, and researchers to incorporate track-and-trace into regulatory systems by other national regulatory authorities.

Immunity and Coagulation in COVID-19.

Discovered in late 2019, the SARS-CoV-2 coronavirus has caused the largest pandemic of the 21st century, claiming more than seven million lives. In most cases, the COVID-19 disease caused by the SARS-CoV-2 virus is relatively mild and affects only the upper respiratory tract; it most often manifests itself with fever, chills, cough, and sore throat, but also has less-common mild symptoms. In most cases, patients do not require hospitalization, and fully recover. However, in some cases, infection with the SARS-CoV-2 virus leads to the development of a severe form of COVID-19, which is characterized by the development of life-threatening complications affecting not only the lungs, but also other organs and systems. In particular, various forms of thrombotic complications are common among patients with a severe form of COVID-19. The mechanisms for the development of thrombotic complications in COVID-19 remain unclear. Accumulated data indicate that the pathogenesis of severe COVID-19 is based on disruptions in the functioning of various innate immune systems. The key role in the primary response to a viral infection is assigned to two systems. These are the pattern recognition receptors, primarily members of the toll-like receptor (TLR) family, and the complement system. Both systems are the first to engage in the fight against the virus and launch a whole range of mechanisms aimed at its rapid elimination. Normally, their joint activity leads to the destruction of the pathogen and recovery. However, disruptions in the functioning of these innate immune systems in COVID-19 can cause the development of an excessive inflammatory response that is dangerous for the body. In turn, excessive inflammation entails activation of and damage to the vascular endothelium, as well as the development of the hypercoagulable state observed in patients seriously ill with COVID-19. Activation of the endothelium and hypercoagulation lead to the development of thrombosis and, as a result, damage to organs and tissues. Immune-mediated thrombotic complications are termed "immunothrombosis". In this review, we discuss in detail the features of immunothrombosis associated with SARS-CoV-2 infection and its potential underlying mechanisms.

Association between SARS-CoV-2 infection before the age of two and child development.

To compare the differences in child development between children who contracted COVID-19 after February 1st, 2022, the period when the B.1.1.529 variant outbreak began to peak in Thailand, and those who did not. A prospective cohort study was conducted in an outpatient pediatric clinic at a tertiary hospital in southern Thailand. COVID-19 was diagnosed based on the results of an FDA-approved antigen test or RT-PCR using a swab sample collected from the nasopharynx, nose, or throat. Child development was assessed using the Ages and Stages Questionnaire, Third Edition (ASQ-3). Of the 336 participants, 180 (53.6%) had a history of COVID-19. Almost all of them had mild COVID-19. The mean (SD) age at infection was 1.3 (0.3) years, and the median (IQR) duration between infection and ASQ-3 assessment was 193.5 (167.8, 216.2) days. The ASQ-3 scores at the ages of 18 (n = 166; 90 COVID-19 positive) and 24 months (n = 170; 90 COVID-19 positive) revealed no statistically significant differences between children with and without a history of COVID-19. Both groups had comparable proportions of developmental scores <1 SD below the mean. Mild COVID-19 in young children did not increase the risk of developmental delays. This cohort study was conducted during the Omicron pandemic. Of the 336 children, no clinical or statistically significant differences were observed in the scores of the Ages & Stages Questionnaire, Third Edition, at 18 or 24 months of age among the 180 participants with a history of mild SARS-CoV-2 infection, at an average of 6 months post-infection, and those without. The findings suggest that mild SARS-CoV-2 infection before the age of 2 years is not associated with developmental delays. Strategies to prevent severe SARS-CoV-2 infection in young children, especially COVID-19 immunization, need to be highlighted.

Evaluation of knowledge, attitude and practice (KAP) of pharmacy students’ acceptance of COVID-19 vaccines in South India

Purpose: To assess South Indian pharmacy students' knowledge, attitudes and practices (KAP) regarding adherence to COVID-19 immunization guidelines. Methods: A six-month prospective cross-sectional study was conducted among KMCH College of Pharmacy, Coimbatore pharmacy students. The 39 validated questions on knowledge, attitudes, practices, and concerns about the COVID-19 vaccine were used to grade replies using 3-point and 5- point Likert scales. IBM SPSS Statistics for Windows, Version 23.0, was used to analyze the data. Results: The survey was completed by a total of 271 pharmacy students. A majority (59 %) of students possessed adequate knowledge (p = 0.0003), and 92 % were willing to receive COVID-19 vaccinations. The majority of respondents have implemented COVID-19-appropriate practices. Majority of information sources (52 %) were from healthcare providers. Conclusion: Pharmacy students in South India have a fair knowledge of COVID-19 vaccination. More effort is required to improve awareness on this subject.

Rural community pharmacists' willingness to receive, administer, and recommend COVID-19 vaccines after the First U.S. vaccine rollout

IntroductionVaccines remain the cornerstone for prevention of COVID-19. Particularly in rural areas, community pharmacists are among the most accessible healthcare professionals. Their advocacy for immunization can help overcome patients' vaccine hesitancy and close the disparity gap between rural and urban regions. This study explored factors influencing the willingness to recommend and administer COVID-19 vaccines among rural community pharmacists after the first U.S. vaccine rollout. MethodsA convenience sample of rural community pharmacists completed a selfadministered, validated paper/online survey (n = 86, 23.4% response rate). Measures included COVID-19 vaccination status, perceived benefits of offering COVID-19 immunization services at the pharmacy, and willingness to recommend and administer COVID-19 vaccines. Descriptive, bivariate, and multivariate statistics were used to analyze potential nonresponse bias, survey responses, and associations between variables as appropriate. Alpha was set at 0.05. ResultsThe proportion of pharmacists who were vaccinated against COVID-19 was 79.1%. Over 75% of participants were in favor of recommending COVID-19 immunizations to eligible family members and patients and almost 85% agreed that they would administer COVID-19 vaccines to their patients. Most pharmacists perceived COVID-19 immunization services to be beneficial, such as attracting more patients into the pharmacy (81.2%), increasing pharmacy revenue (75.3%), and enhancing relationships with local clinics/public health agencies (74.1%). COVID-19 vaccination status and the perceived benefit of offering immunization services at the pharmacy were significantly associated with pharmacists' willingness to recommend and administer COVID-19 vaccines. ConclusionThe relatively high rates of COVID-19 vaccination uptake and the strong willingness of rural community pharmacists to recommend and administer COVID-19 vaccines, after the first national vaccine rollout, were encouraging. The findings underscore the importance of engaging rural community pharmacists in efforts to prepare for and respond to future pandemics and public health crises.

Implementation of a Health Communication Strategy in the Success of the COVID-19 Vaccine Program in West Jakarta

The research will focus on the West Jakarta Health Service's Communication Strategy for Disseminating the COVID-19 Vaccine. This research is inspired by the concern that the Jakarta COVID-19 vaccination achievement remains below target, particularly for the elderly, at 64.85 percent for the first dose and 58.44 percent for the second dose in October 2021. There are many obstacles such as hoax news and low public knowledge about vaccines. This research focuses on how to examine the Jakarta Health Office's communication strategy in inviting people to implement COVID-19 immunization. This research will expand on health communication concepts and theories by employing Push, Pull, and Pass communication tactics. A variety of doctors, and health professionals were interviewed for this study. The study results show that the push approach is implemented by opening direct vaccine centres, pulling through persuasively, door prizes, basic food packages, cooperation cross-sectors, and passes with public figure testimonials. The job of Dasawisma cadres is critical because they are the ones who directly persuade the people in simple languages like Javanese and Sundanese. The community also trusts the Dasawisma cadres because they are previously acquainted. The City of West Jakarta achieved 98% of the first dosage of the vaccination, and 65% dosage 2nd in December 2022. Keywords: Health communication, vaccine, communication strategies, COVID-19, Dasawisma.

Parents' Willingness to Vaccinate Their Children Aged From 6 Months to Under 5 Years With COVID-19 Vaccines.

Despite strides in vaccinating priority groups against COVID-19, children under 5 years in Vietnam are still under-immunized, emphasizing a significant gap in prioritization. This study aimed to assess parental willingness to vaccinate children aged 6 months to under 5 years against COVID-19 in Vietnam and identify influential factors affecting this willingness. Data were collected via a survey of 5960 parents/guardians between May and June 2022. Multinomial logistic regression was employed to analyze the impact of various factors on parents' willingness to vaccinate their children, alongside investigating reasons for reluctance or refusal and preferences for vaccine origins. Approximately 50.5%, 30.2%, and 19.3% of parents were willing, hesitant, and unwilling to vaccinate their children, respectively. Primary reasons for reluctance included concerns about vaccine safety, efficacy, and the severity of the pandemic. The most preferred vaccines originated in the United States. Factors significantly influencing willingness included parents' age, knowledge of COVID-19 and vaccines, residency, education, perception of information sufficiency, children's comorbidities, and family members' vaccination status. Promoting child vaccination habits can boost COVID-19 immunization rates. Targeting hesitancy among parents of children with comorbidities is crucial. Enhancing parental knowledge and leveraging fully vaccinated family members are effective strategies.

Indirect effectiveness of COVID-19 vaccines in the pre-omicron and omicron periods: A nation-wide test-negative case-control study in Brazil

ObjectivesMass COVID-19 immunization campaigns altered the pandemic's progress by protecting the vaccine recipient and reducing transmission. However, evidence for indirect vaccine effectiveness (IVE) is limited due to the difficulties of ascertaining this type of protection. MethodsUsing linked national Brazilian databases, we adapted the test-negative design to evaluate the IVE against symptomatic infection. We analyzed data from January 1 to December 1, 2021 (pre-omicron) and January 1 to April 30, 2022 (omicron BA.1 and BA.2). We compared the probability of testing positive across various levels of second ancestral-strain monovalent COVID-19 vaccine dose coverage, including only unvaccinated individuals in the main analysis and both vaccinated and unvaccinated individuals in additional analyses. Sensitivity analysis focused on children younger than 12 years who did not have access to COVID-19 vaccines during the pre-omicron period. ResultsWe included 11,039,315 unvaccinated individuals tested during the pre-omicron study period. IVE was minimal until 30% vaccination coverage (<10%), then it followed a dose-dependent pattern, peaking at 37.7 (95% confidence interval 32-42.8) at 70% coverage. For children younger than 12 years, IVE peaked at 59.8% (95% confidence interval 52.7-65.9) at 70% coverage. During the omicron period, IVE remained constant at about 5% across all comparisons. ConclusionsOur findings confirm that high vaccination coverage using vaccines that prevent infection indirectly protects the community. However, IVE was substantially higher during the pre-omicron period.

Evaluation of Vaccine Strategies among Healthcare Workers during COVID-19 Omicron Outbreak in Taiwan.

This study aimed to assess the reactogenicity and immunogenicity of various SARS-CoV-2 vaccines and compare their protective effects against COVID-19 among healthcare workers (HCWs) during the Omicron outbreak in Taiwan. Conducted from March 2021 to July 2023, this prospective observational study included healthy HCWs without prior COVID-19 immunization. Participants chose between adenovirus-vectored (AstraZeneca), mRNA (Moderna, BioNTech-Pfizer), and protein-based (Medigen, Novavax) vaccines. Blood samples were taken at multiple points to measure neutralizing antibody (nAb) titers, and adverse events (AEs) were recorded via questionnaires. Of 710 HCWs, 668 (94.1%) completed three doses, and 290 (40.8%) received a fourth dose during the Omicron outbreak. AEs were more common with AstraZeneca and Moderna vaccines, while Medigen caused fewer AEs. Initial nAb titers were highest with Moderna but waned over time regardless of the vaccine. Booster doses significantly increased nAb titers, with the highest levels observed in Moderna BA1 recipients. The fourth dose significantly reduced COVID-19 incidence, with Moderna BA1 being the most effective. Regular booster doses, especially with mRNA and adjuvant-protein vaccines, effectively enhance nAb levels and reduce infection rates, providing critical protection for frontline HCWs during variant outbreaks.

COVID-19 mRNA vaccines induce robust levels of IgG but limited amounts of IgA within the oronasopharynx of young children.

Understanding antibody responses to SARS-CoV-2 vaccination is crucial for refining COVID-19 immunization strategies. Generation of mucosal immune responses, including mucosal IgA, could be of potential benefit to vaccine efficacy, yet limited evidence exists regarding the production of mucosal antibodies following the administration of current mRNA vaccines to young children. We measured the levels of antibodies against SARS-CoV-2 from a cohort of children under 5 years of age (N=24) undergoing SARS-CoV-2 mRNA vaccination (serially collected, matched serum and saliva samples) or in a convenience sample of children under 5 years of age presenting to pediatric emergency department (nasal swabs, N=103). Further, we assessed salivary and nasal samples for the ability to induce SARS-CoV-2 spike-mediated neutrophil extracellular traps (NET) formation. Longitudinal analysis of post-vaccine responses in saliva revealed the induction of SARS-CoV-2 specific IgG but not IgA. Similarly, SARS-CoV-2 specific IgA was only observed in nasal samples obtained from previously infected children with or without vaccination, but not in vaccinated children without a history of infection. In addition, oronasopharyngeal samples obtained from children with prior infection were able to trigger enhanced spike-mediated NET formation, and IgA played a key role in driving this process. Despite the induction of specific IgG in the oronasal mucosa, current intramuscular vaccines have limited ability to generate mucosal IgA in young children. These results confirm the independence of mucosal IgA responses from systemic humoral responses following mRNA vaccination and suggest potential future vaccination strategies for enhancing mucosal protection in this young age group.

How Safe Are COVID-19 Vaccines in Individuals with Immune-Mediated Inflammatory Diseases? The SUCCEED Study.

We were tasked by Canada's COVID-19 Immunity Task Force to describe severe adverse events (SAEs) associated with emergency department (ED) visits and/or hospitalizations in individuals with immune-mediated inflammatory diseases (IMIDs). At eight Canadian centres, data were collected from adults with rheumatoid arthritis (RA), axial spondyloarthritis (AxS), systemic lupus (SLE), psoriatic arthritis (PsA), and inflammatory bowel disease (IBD). We administered questionnaires, analyzing SAEs experienced within 31 days following SARS-CoV-2 vaccination. About two-thirds (63%) of 1556 participants were female; the mean age was 52.5 years. The BNT162b2 (Pfizer) vaccine was the most common, with mRNA-1273 (Moderna) being second. A total of 49% of participants had IBD, 27.4% had RA, 14.3% had PsA, 5.3% had SpA, and 4% had SLE. Twelve (0.77% of 1556 participants) SAEs leading to an ED visit or hospitalization were self-reported, occurring in 11 participants. SAEs included six (0.39% of 1556 participants) ED visits (including one due to Bell's Palsy 31 days after first vaccination) and six (0.39% of 1556 participants) hospitalizations (including one due to Guillain-Barré syndrome 15 days after the first vaccination). Two SAEs included pericarditis, one involved SLE (considered a serious disease flare), and one involved RA. Thus, in the 31 days after SARS-CoV-2 vaccination in our IMID sample, very few serious adverse events occurred. As SARS-CoV2 continues to be a common cause of death, our findings may help optimize vaccination acceptance.

COVID-19 immunization status in children compared to their parents: a retrospective review at an upstate NY medicine/pediatrics practice

BackgroundThis study aimed to investigate the relationship between parent and child COVID-19 immunization series completion using vaccine records.MethodsA cross-sectional chart review was performed on parent and child patients at the Albany Medical Center Internal Medicine and Pediatrics practice. Patient and parent demographic data, COVID-19 immunization status, and health care worker status was collected. Patient data was further separated into 2 cohorts to account for vaccine eligibility among child age groups, with 5–11 years and 6 months-4 years cohorts. Chi square or Fisher’s exact test was used where appropriate.ResultsAcross both cohorts, 371 child patients were identified and cross-matched with corresponding parents. Neither cohort offered evidence linking child immunization series completion with the child’s race, ethnicity, or county of residence. However, rates of series completion were higher for children with private insurance versus public options in both the 5–11 years and 6 months-4 years cohorts (both p < 0.001). Children were more likely to be immunized against COVID-19 if their parents were fully immunized against COVID-19 (both p < 0.05). Children aged 6 months-4 years were more likely to be immunized against COVID-19 if their parent was a health care worker (p = 0.038).ConclusionsThis study demonstrates a significance between child insurance status, as well as between parental vaccination status and child vaccination status. Only children under 5 years were more likely to be vaccinated against COVID-19 if their parent was a health care worker.

Emerging Omicron Subvariants EG.5 and BA.2.86: Implications for COVID-19 Immunity and Surveillance

The SARS-CoV-2 virus, responsible for the COVID-19 pandemic, has continuously evolved since its emergence. Among its variants, the Omicron lineage has become globally dominant, displaying a diverse range of sublineages. Two significant sub lineages within Omicron are EG.5 and BA.2.8, which have gained attention due to their unique characteristics and potential implications. EG.5 is characterized by a constellation of mutations, including N501Y, L452R, and D614G. Similarly, BA.2.8 carries the L452Q and P681R mutations, which enhance its ability to evade antibodies elicited by prior infection or vaccination. Similar to those in the EG.5, the clinical severity and impact of BA.2.8 on public health measures are still being assessed. These sublineages, with their unique genetic profiles and transmissibility characteristics, pose challenges to virulence response efforts. Continued surveillance, genomic sequencing, and research are essential to understand their behavior, assess their impact, and inform public health strategies accordingly. By a comprehensive synthesis of the literature, genomic data, and epidemiological insights, this study provides an analysis of Omicron mutations’ transmission dynamics, and clinical implications associated with these variants. The significance of variant surveillance in informing public health responses to the COVID-19 pandemic is underscored, highlighting the critical role of genomic sequencing in tracking viral evolution and guiding interventions. This manuscript aimed to elucidate the mechanisms underlying variant emergence, assess vaccine effectiveness against emerging strains, and explore the broader implications for global public health. This study provides insights into vaccine-induced immunity and the potential impact of variants on vaccine efficacy. Overall, this communication aims to inform public health practitioners, policymakers, and researchers engaged in the battle against COVID-19, offering actionable insights to mitigate the spread of the virus and improve pandemic response strategies.

Parents' views on pediatric COVID-19 vaccine in Saudi Arabia.

To end the COVID-19 pandemic, we need to reach herd immunity. A successful pediatric COVID-19 immunization program is the only way to achieve this goal. The objective of this study was to determine the views of parents in Saudi Arabia on the COVID-19 vaccine in children. This cross-sectional study took place within the Family Medicine Pediatric clinics at the King Faisal Specialist Hospital and Research Center (KFSH and RC). All parents of patients of Family Medicine Pediatric Clinics at KFSH and RC, Riyadh, were invited to participate in this study between January 2022 and June 2022. A culturally sensitive and specially designed questionnaire was administered using an interview-based model. Safety concerns were the primary reason for vaccine hesitancy among parents, with 29.7% of parents expressing concerns about side effects and 25.1% not knowing where to get reliable information about vaccines. Negative information and lack of perceived need were also important factors, with 17.1% and 18.3% of parents citing these reasons, respectively. Poor knowledge about vaccines was a significant predictor of parental vaccine hesitancy. Mothers had more concerns about the efficacy and safety of vaccines than fathers. Our study demonstrated a negative attitude toward the pediatric COVID-19 vaccine among parents in Saudi Arabia. A higher level of awareness about the vaccine was significantly associated with planning on having the vaccine. There is a need for effective awareness programs for better pediatric COVID-19 vaccine-related education to increase the acceptance of the vaccine among parents in Saudi Arabia.

Safety and Immunogenicity of the Intranasal Vaccine Candidate Mambisa and the Intramuscular Vaccine Abdala Used as Booster Doses for COVID-19 Convalescents: A Randomized Phase 1-2 Clinical Trial.

A phase 1-2, prospective, multicenter, randomized, open-label clinical trial (Code RPCEC00000382), with parallel groups, involving 1161 participants, was designed to assess the safety and immunogenicity of two Cuban COVID-19 vaccines (Mambisa and Abdala) in boosting COVID-19 immunity of convalescent adults after receiving one dose of either vaccine. The main safety outcome was severe vaccination adverse events occurring in <5% of vaccinees. Main immunogenicity success endpoints were a ≥4-fold anti-RBD IgG seroconversion or a ≥20% increase in ACE2-RBD inhibitory antibodies in >55% of vaccinees in Phase 1 and >70% in Phase 2. Neutralizing antibody titers against SARS-CoV-2 variants were evaluated. Both vaccines were safe-no deaths or severe adverse events occurred. Mild intensity adverse events were the most frequent (>73%); headaches predominated for both vaccines. Phase 1 responders were 83.3% (p = 0.0018) for Abdala. Mambisa showed similar results. Phase 2 responders were 88.6% for Abdala (p < 0.0001) and 74.2% for Mambisa (p = 0.0412). In both phases, anti-RBD IgG titers, inhibition percentages and neutralizing antibody titers increased significantly after the booster dose. Both vaccines were safe and their immunogenicity surpassed the study endpoints.

A retrospective survey on the effectiveness of vaccines administered to individuals in China with regard to inactivated COVID-19 vaccines, Ad5-nCoV and/or aerosolized Ad5-nCoV

ABSTRACT We administered a questionnaire to participants who received different vaccination regimens to evaluate the effectiveness of Ad5-vectored COVID-19 vaccines. The results showed that administration of intramuscular Ad5-nCoV provided 21.32% more protection against SARS-CoV-2 infection than that of the inactivated COVID-19 vaccine in people who had received only one type of COVID-19 vaccine. Furthermore, aerosolized Ad5-nCoV exhibited good protection, whether it was administered as a homologous booster to people vaccinated with the intramuscular Ad5-nCoV or as a heterologous booster to people vaccinated with inactivated COVID-19 vaccines. Our research indicates that Ad5-nCoV is an effective booster. This finding supports the future selection of COVID-19 immunization strategies.