Objectives: The World Health Organization recently revised their recommendations and considered healthy children and adolescents as low priority group for COVID-19 vaccine. This review comprehensively assessed existing clinical evidence on COVID-19 vaccine in 12-17 years old. Methods: Included in this review were any type of study that investigated the efficacy, immunogenicity, safety, and effectiveness of COVID-19 vaccine on protection against SARS-COV-2 infection in 12-17 years old. Various electronic databases were searched up to March 15, 2023. Studies were screened, data extracted, risk of bias appraised, and certainty of evidence was judged using GRADE. Review Manager 5.4 was used to estimate pooled effects. Difference between the two groups was described as mean difference for continuous variables and as relative risk or odds ratio for categorical variables. Results: There were six randomized controlled trials and 16 effectiveness studies (8 cohorts and 8 case control). Low certainty evidence showed that BNT162b2 (Pfizer) was effective, immunogenic, and safe in healthy adolescents. There were 15 effectiveness studies on BNT162b2 (Pfizer) in healthy adolescent and one on immunocompromised patients. It was protective against infection with any of the variants, with higher protection against Delta than Omicron. BNT162b2 is protective against hospitalization and emergency and urgent care (high certainty); and critical care and MIS-C (low). Very low certainty evidence noted that BNT 162b2 was also immunogenic in 12-21 years old with rheumatic diseases while on immunomodulatory treatment but with possible increased exacerbation of illness. Low certainty evidence demonstrated that mRNA-1273 (Moderna) was effective, immunogenic, and safe. Low to very low certainty evidence were noted on the safety and immunogenicity of two vector base vaccines (ChAdOx1-19 and Ad5 vector COVID vaccine) and two inactivated vaccines (CoronaVac and BBIBP CorV). Conclusion There is presently low certainty evidence on the use of RNA vaccines in 12-17 years old. The recommendation on its use is weak. There is presently insufficient evidence for the use of inactivated and vector-based COVID-19 vaccines. Different countries should consider whether to vaccinate healthy adolescent without comprising the other recommended immunization and health priorities that are crucial for this age group. Other factors including cost-effectiveness of vaccination and disease burden should be accounted.
mRNA Vaccines ; Vaccines, Inactivated

Background: In response to the pandemic brought about by COVID-19, vaccines were developed immediately. Together with adhering to safety protocols, vaccines are needed to help decrease the mortality and morbidity. As with any other, COVID-19 vaccines are evaluated based on efficacy and safety. Real world data is important in the recommendation of vaccines. Objectives: This study aims to assess the short-term safety of BNT162b2 COVID-19 vaccines administered to Filipino adolescents from October 15, 2021 to December 15, 2021 at the Philippine General Hospital. The number and type of local and systemic reaction within 7 days of vaccination were determined. Methods: This is a retrospective cohort study. The review of the recorded events was done through an electronic diary that was accessed from the official Electronic Medical Records of University of the Philippines-Philippine General Hospital (UP-PGH). This included solicited and prespecified local and systemic reactions that occurred within 7 days of receipt of vaccine dose. Descriptive statistics was used to present the data. Results: Out of the 1,756 BNT162b2 vaccines administered (Dose 1- 890; Dose 2- 866), 13% (N=221) indicated having adverse reaction. Injection site pain was the overall most common reaction with majority (81%) experiencing it within 7 days of vaccination. Systemic reactions made up 60% of the reactions after Dose 1 and 85% of the reactions after Dose 2. This includes tiredness, headache and fever. None of the reactions required hospitalization or further workup. Conclusion BNT162b2 vaccine has a good safety profile among adolescents vaccinated at UP-PGH, since most of the reported adverse events within 7 days of vaccination were local and systemic reactogenic reactions that did not necessitate hospitalization or work-up. No serious adverse events were reported. Further follow-up is suggested to assess longer term safety.
COVID-19 Vaccines ; mRNA Vaccines

A large number of studies have demonstrated that mRNA vaccine has been characterized as a technique with good safety, strong immunogenicity and high developmental potential, which makes it have broad prospects in immunotherapy. In recent years, the stability and in vivo delivery efficiency of mRNA vaccines have been largely addressed by the progresses in mRNA engineering and delivery innovation. And some mRNA vaccines are now clinical approved or in preclinical trials. Here, we summarize current knowledge on the research advances, technology, and application in major infectious diseases in humans and animals of mRNA vaccines, with the aim to provide a reference for improving the development of novel mRNA vaccines.
Animals ; Humans ; Communicable Diseases ; Vaccines, Synthetic/genetics* ; mRNA Vaccines

Cardiovascular Diseases/prevention & control* ; Humans ; RNA, Messenger ; Vaccines ; Vaccines, Synthetic/genetics* ; mRNA Vaccines

Messenger RNA (mRNA) vaccines emerge as promising vaccines to prevent infectious diseases. Compared with traditional vaccines, mRNA vaccines present numerous advantages, such as high potency, safe administration, rapid production potentials, and cost-effective manufacturing. In 2020, two COVID-19 vaccines (BNT162b2 and mRNA-1273) were approved by the Food and Drug Administration (FDA). The two vaccines showed high efficiency in combating COVID-19, which indicates the great advantages of mRNA technology in developing vaccines against emergent infectious diseases. Here, we summarize the type, immune mechanisms, modification methods of mRNA vaccines, and their applications in preventing infectious diseases. Current challenges and future perspectives in developing mRNA vaccines are also discussed.
United States ; Humans ; mRNA Vaccines ; BNT162 Vaccine ; COVID-19 Vaccines/genetics* ; Communicable Diseases ; RNA, Messenger/genetics*

BACKGROUND: Data on the immunogenicity and safety of heterologous immunization schedules are inconsistent. This study aimed to evaluate the immunogenicity and safety of homologous and heterologous immunization schedules. METHODS: Multiple databases with relevant studies were searched with an end date of October 31, 2021, and a website including a series of Coronavirus disease 2019 studies was examined for studies before March 31, 2022. Randomized controlled trials (RCTs) that compared different heterologous and homologous regimens among adults that reported immunogenicity and safety outcomes were reviewed. Primary outcomes included neutralizing antibodies against the original strain and serious adverse events (SAEs). A network meta-analysis (NMA) was conducted using a random-effects model. RESULTS: In all, 11 RCTs were included in the systematic review, and nine were ultimately included in the NMA. Among participants who received two doses of CoronaVac, another dose of mRNA or a non-replicating viral vector vaccine resulted in a significantly higher level of neutralizing antibody than a third CoronaVac 600 sino unit (SU); a dose of BNT162b2 induced the highest geometric mean ratio (GMR) of 15.24, 95% confidence interval [CI]: 9.53-24.39. Following one dose of BNT162b2 vaccination, a dose of mRNA-1273 generated a significantly higher level of neutralizing antibody than BNT162b2 alone (GMR = 1.32; 95% CI: 1.06-1.64), NVX-CoV2373 (GMR = 1.60; 95% CI: 1.16-2.21), or ChAdOx1 (GMR = 1.80; 95% CI: 1.25-2.59). Following one dose of ChAdOx1, a dose of mRNA-1273 was also more effective for improving antibody levels than ChAdOx1 (GMR = 11.09; 95% CI: 8.36-14.71) or NVX-CoV2373 (GMR = 2.87; 95% CI: 1.08-3.91). No significant difference in the risk for SAEs was found in any comparisons. CONCLUSIONS: Relative to vaccination with two doses of CoronaVac, a dose of BNT162b2 as a booster substantially enhances immunogenicity reactions and has a relatively acceptable risk for SAEs relative to other vaccines. For primary vaccination, schedules including mRNA vaccines induce a greater immune response. However, the comparatively higher risk for local and systemic adverse events introduced by mRNA vaccines should be noted. REGISTRATION PROSPERO; https://www.crd.york.ac.uk/PROSPERO/ ; No. CRD42021278149.
Adult ; Humans ; BNT162 Vaccine ; 2019-nCoV Vaccine mRNA-1273 ; Network Meta-Analysis ; Immunization Schedule ; COVID-19/prevention & control* ; COVID-19 Vaccines/adverse effects* ; Viral Vaccines ; mRNA Vaccines ; Antibodies, Neutralizing ; Antibodies, Viral

INTRODUCTION: Despite reports suggesting an association between COVID-19 mRNA vaccination and pericarditis and myocarditis, detailed nationwide population-based data are sparsely available. We describe the incidence of pericarditis and myocarditis by age categories and sex after COVID-19 mRNA vaccination from a nationwide mass vaccination programme in Singapore. METHODS: The incidence of adjudicated cases of pericarditis and myocarditis following COVID-19 mRNA vaccination that were reported to the vaccine safety committee between January to July 2021 was compared with the background incidence of myocarditis in Singapore. RESULTS: As of end July 2021, a total of 34 cases were reported (9 pericarditis only, 14 myocarditis only, and 11 concomitant pericarditis and myocarditis) with 7,183,889 doses of COVID-19 mRNA vaccine administered. Of the 9 cases of pericarditis only, all were male except one. The highest incidence of pericarditis was in males aged 12-19 years with an incidence of 1.11 cases per 100,000 doses. Of the 25 cases of myocarditis, 80% (20 cases) were male and the median age was 23 years (range 12-55 years) with 16 cases after the second dose. A higher-than-expected number of cases were seen in males aged 12-19 and 20-29 years, with incidence rates of 3.72 and 0.98 case per 100,000 doses, respectively. CONCLUSION Data from the national registry in Singapore indicate an increased incidence of pericarditis and myocarditis in younger men after COVID-19 mRNA vaccination.
Adolescent ; Adult ; COVID-19/prevention & control* ; COVID-19 Vaccines/adverse effects* ; Child ; Female ; Humans ; Male ; Middle Aged ; Myocarditis/etiology* ; Pericarditis/etiology* ; RNA, Messenger ; SARS-CoV-2 ; Vaccination/adverse effects* ; Vaccines, Synthetic ; Young Adult ; mRNA Vaccines

OBJECTIVES: In this article, we aim to share our experience in the hospital reorganization made to conduct the SARS-CoV-2 vaccination campaign, based on the principles of flexibility and adaptability. STUDY DESIGN: A descriptive study. METHODS: The data concerning the organization of the vaccination campaign were taken from the operative protocol developed by the hospital dedicated task force, composed by experts in hygiene, public health, occupational medicine, pharmacists, nurses, hospital quality, and disaster managers. Data about the numbers of vaccine administered daily were collected by the Innovation and Development Operative Unit database. RESULTS: Vaccinations against COVID-19 started across the EU on the 27th of December 2020. The first phase of the vaccination campaign carried out in our hospital was directed to healthcare workers immunization including medical residents, social care operators, administrative staff and technicians, students of medicine, and health professions trainees. The second phase was enlarged to the coverage of extremely fragile subjects. Thanks to the massive employment of healthcare workers and the establishment of dynamic pathways, it was possible to achieve short turnaround times and a large number of doses administered daily, with peaks of 870 vaccines per day. From the 27th of December up to the 14th of March a total of 26,341 doses of Pfizer have been administered. 13,584 were first doses and 12,757 were second doses. From the 4th to the 14th of March, 296 first doses of Moderna were dispensed. It was necessary to implement adequate spaces and areas adopting anti-contagion safety measures: waiting area for subjects to be vaccinated, working rooms for the dilution of the vaccine and the storage of the material, vaccination rooms, post-vaccination observation areas, room for observation, and treatment of any adverse reactions, with an emergency cart available in each working area. CONCLUSIONS The teaching hospital of Pisa faced the beginning of the immunization campaign readjusting its spaces, planning an adequate hospital vaccination area and providing an organization plan to ensure the achievement of the targets of the campaign. This represented a challenge due to limited vaccine doses supplied and the multisectoral teams of professionals to coordinate in the shortest time and the safest way possible. The organizational model adopted proved to be adequate and therefore exploited also for the second phase aimed to extremely fragile subjects.
2019-nCoV Vaccine mRNA-1273 ; BNT162 Vaccine ; COVID-19/prevention & control* ; COVID-19 Vaccines/administration & dosage* ; Hospitals, Teaching/organization & administration* ; Humans ; Immunization Programs/organization & administration* ; Italy/epidemiology* ; SARS-CoV-2/immunology*