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

Protection against severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection of inactivated vaccines is not well characterized in people with comorbidities, who are at high risk of severe infection. We compared the risk of SARS-CoV-2 infection after complete vaccination with Sinopharm/BBIBP in people with comorbidities (e.g., autoimmune diseases, cardiovascular disease, chronic lung disease, and diabetes) with healthy individuals using a Cox-proportional hazard model. In July-September 2021, a total of 10 548 people (comorbidities, 2143; healthy, 8405) receiving the complete primary series of vaccination with Sinopharm/BBIBP in Bangkok, Thailand were prospectively followed for SARS-CoV-2 infection through text messaging and telephone interviewing for 6 months. A total of 295 infections from 284 participants were found. HRs (95% CI) of individuals with any comorbidities did not increase (unadjusted, 1.02 (0.77-1.36), P = 0.89; adjusted, 1.04 (0.78-1.38), P = 0.81). HRs significantly increased in the subgroup of autoimmune diseases (unadjusted, 2.64 (1.09-6.38), P = 0.032; adjusted, 4.45 (1.83-10.83), P = 0.001) but not in cardiovascular disease, chronic lung disease, or diabetes. The protection against SARS-CoV-2 infection of the Sinopharm vaccine was similar in participants with any comorbidities vs. healthy individuals. However, the protection appeared lower in the subgroup of autoimmune diseases, which may reflect suboptimal immune responses among these people.
Humans ; COVID-19/prevention & control* ; Vaccines, Inactivated ; COVID-19 Vaccines ; SARS-CoV-2 ; Cardiovascular Diseases ; Prospective Studies ; Thailand ; Autoimmune Diseases ; Diabetes Mellitus/epidemiology*

Objective: To understand the vaccination status of enterovirus type 71 (EV71) inactivated vaccines in China from 2017 to 2021 and provide evidence for making policy on immunization strategy against hand, foot and mouth disease (HFMD). Methods: Using the reported dose number of EV71 vaccination and birth cohort population data collected by the China immunizaiton program information system to estimate the cumulative coverage of EV71 vaccine by the end of 2021 among the birth cohorts since 2012 at national, provincial, and prefecture levels, and analyze the correlation between the vaccination coverage and the potential influencing factors. Results: As of 2021, the estimated cumulative vaccination coverage of the EV71 vaccine was 24.96% in birth cohorts since 2012. The cumulative vaccination coverage was between 3.09% and 56.59% in different provinces, between 0 and 88.17% in different prefectures. There was a statistically significant correlation between vaccination coverage in different regions and the region's previous HFMD prevalence and disposable income per capita. Conclusions: Since 2017, the EV71 vaccines have been widely used nationwide, but the coverage of EV71 vaccination varies greatly among regions. Vaccination coverage is higher in relatively developed regions, and the intensity of previous epidemic of HFMD may have a certain impact on the acceptance of the vaccine and the pattern of immunization service. The impact of EV71 vaccination on the epidemic of HFMD requires further studies.
Humans ; Enterovirus A, Human ; Hand, Foot and Mouth Disease/prevention & control* ; Vaccines, Inactivated ; Viral Vaccines ; Enterovirus ; Vaccination ; China/epidemiology*

Humans ; Vaccines, Inactivated ; COVID-19/prevention & control* ; Vaccination ; Viral Vaccines ; Immunity ; Antibodies, Viral

Seasonal influenza has a high disease burden, and children infected with influenza are prone to multiple complications. Influenza vaccination is effective in preventing infection and reducing risks of severe diseases and complications. Influenza vaccines are trivalent and quadrivalent, depending on the components of the vaccine. According to the hemagglutinin content, it can be divided into full dose and half dose of influenza vaccine for children. The findings from clinical trials and real-world studies suggested, the full-dose influenza vaccine as in adults has the same safety profile and higher immunogenicity in children aged 6 to 35 months. The application of full-dose influenza vaccine in children aged 6 to 35 months can greatly improve the flexibility and convenience of vaccination, and help reduce the workload in the process.
Child ; Adult ; Infant ; Humans ; Child, Preschool ; Influenza Vaccines ; Influenza, Human/prevention & control* ; Vaccination ; Vaccines, Inactivated ; Antibodies, Viral

Influenza is an acute respiratory infectious disease caused by the influenza virus, which seriously affects human health. The influenza virus has frequent antigenic drifts that can facilitate escape from pre-existing population immunity and lead to the rapid spread and annual seasonal epidemics. Influenza outbreaks occur in crowded settings, such as schools, kindergartens, and nursing homes. Seasonal influenza epidemics can cause 3-5 million severe cases and 290 000-650 000 respiratory disease-related deaths worldwide every year. Pregnant women, infants, adults 60 years and older, and individuals with comorbidities or underlying medical conditions are at the highest risk of severe illness and death from influenza. Given the ongoing COVID-19 pandemic, some provinces in southern China had a summer peak of influenza. SARS-CoV-2 may co-circulate with influenza and other respiratory viruses in the upcoming winter-spring influenza season. Annual influenza vaccination is an effective way to prevent influenza, reduce influenza-related severe illness and death, and reduce the harm caused by influenza-related diseases and the use of medical resources. The currently approved influenza vaccines in China include trivalent inactivated influenza vaccine (IIV3), quadrivalent inactivated influenza vaccine (IIV4), and trivalent live attenuated influenza vaccine (LAIV3). IIV3 is produced as a split virus vaccine and subunit vaccine; IIV4 is produced as a split virus vaccine; and LAIV3 is a live, attenuated virus vaccine. Except for some jurisdictions in China, the influenza vaccine is a non-immunization program vaccine-voluntarily and self-paid. China CDC has issued 'Technical Guidelines for Seasonal Influenza Vaccination in China' every year from 2018 to 2021. Over the past year, new research evidence has been published at home and abroad. To better guide the prevention and control of influenza and vaccination in China, the National Immunization Advisory Committee (NIAC) Influenza Vaccination Technical Working Group updated and revised the 2021-2022 Technical Guidelines with the latest research progress into the 'Technical Guidelines for Seasonal Influenza Vaccination in China (2022-2023)'. The new version has updated five key areas: (1) new research evidence-especially research conducted in China-has been added, including new estimates of the burden of influenza disease, assessments of influenza vaccine effectiveness and safety, and analyses of the cost-effectiveness of influenza vaccination; (2) policies and measures for influenza prevention and control that were issued by the government over the past year; (3) influenza vaccines approved for marketing in China this year; (4) composition of trivalent and quadrivalent influenza vaccines for the 2022-2023 northern hemisphere influenza season; and (5) recommendations for influenza vaccination during the 2022-2023 influenza season. The 2022-2023 Guidelines recommend that vaccination clinics provide influenza vaccination services to all people aged 6 months and above who are willing to be vaccinated and have no contraindications to the influenza vaccine. For adults ≥ 18 years, co-administration of COVID-19 and inactivated influenza vaccines in separate arms is acceptable regarding immunogenicity and reactogenicity. For people under 18 years old, there should be at least 14 days between influenza vaccination and COVID-19 vaccination. The Guidelines express no preference for influenza vaccine type or manufacturer-any approved, age-appropriate influenza vaccines can be used. To minimize harm from influenza and limit the impact on the effort to prevent and control COVID-19 in China, the Technical Guidelines recommend priority vaccination of the following high-risk groups during the upcoming 2022-2023 influenza season: (1) healthcare workers, including clinical doctors and nurses, public health professionals, and quarantine professionals; (2) volunteers and staff who provide services and support for large events; (3) people living in nursing homes or welfare homes and staff who take care of vulnerable, at-risk individuals; (4) people who work in high population density settings, including teachers and students in kindergartens and primary and secondary schools, and prisoners and prison staff; and (5) people at high risk of influenza, including adults ≥ 60 years of age, children 6-59 months of age, individuals with comorbidities or underlying medical conditions, family members and caregivers of infants under 6 months of age, and pregnant women. Children 6 months to 8 years of age who receive inactivated influenza vaccine for the first time should receive two doses, with an inter-dose interval of 4 or more weeks. Children who previously received the influenza vaccine and anyone 9 years or older need only one dose. LAIV is recommended only for a single dose regardless of the previous influenza vaccination. Vaccination should begin as soon as influenza vaccines become available and preferably should be completed before the onset of the local influenza season. Repeated influenza vaccination during a single influenza season is not recommended. Vaccination clinics should provide immunization services throughout the epidemic season. Pregnant women can receive inactivated influenza vaccine at any stage of pregnancy. These guidelines are intended for use by staff of CDCs, healthcare workers, maternity and child care institutions and immunization clinic staff members who work on influenza control and prevention. The guidelines will be updated periodically as new evidence becomes available.
Adult ; Infant ; Female ; Pregnancy ; Humans ; Adolescent ; Child, Preschool ; Influenza Vaccines ; Influenza, Human/epidemiology* ; Seasons ; Pandemics ; COVID-19 ; COVID-19 Vaccines ; SARS-CoV-2 ; Vaccination ; China/epidemiology* ; Orthomyxoviridae ; Vaccines, Attenuated ; Vaccines, Combined ; Vaccines, Inactivated

This paper aims to detect the antigens in porcine circovirus type 2 (PCV2) vaccines by high-performance size-exclusion chromatography (HPSEC) coupled with multi-angle laser light scattering (MALLS). With purified inactivated PCV2 and PCV2 virus-like particles (VLP) as references, two inactivated vaccines (a and b) and two VLP vaccines (c and d) for PCV2 from four manufacturers were analyzed by HPSEC-MALLS after demulsification. The antigen peaks in HPSEC-MALLS were identified by PCV2 antigen test strips, Western blotting and transmission electron microscope (TEM). The repeatability and linearity of the method were investigated. The results showed the virus antigens in the two inactivated vaccines were eluted at about 13.3 min in HPSEC. The molecular weight of these antigens was 2.61×10⁶ (±4.34%) Da and 2.40×10⁶ (±2.51%) Da, respectively, as calculated by MALLS. The antigen peaks of the two VLP vaccines also appeared at 13.3 min and the molecular weight was 2.09×10⁶ (±2.94%) Da and 2.88×10⁶ (±11.85%) Da, respectively, which was close to the theoretical molecular weight of PCV2. Moreover, an antigen peak of VLP vaccine c was observed at 11.4 min and the molecular weight was 4.37×10⁶ (±0.42%) Da. The antigen was verified to be the dimer of VLP by TEM. Vaccine d and purified Cap VLP antigens were tested repeatedly, and the RSD of the peak area (n=3) was all < 1.5%, indicating that the method was repeatable. The purified VLP were diluted in serial and tested for linearity. The result suggested good linear relationship between the peak area of VLP or VLP aggregates and the protein concentration of the sample with R² of 0.999 and 0.997, respectively. Thus, the method met the requirement for quantification and aggregate analysis. This method is accurate and efficient in in vitro quality evaluation and improvement of PCV2 vaccine.
Animals ; Antibodies, Viral ; Capsid Proteins ; Chromatography, Gel ; Circoviridae Infections/prevention & control* ; Circovirus ; Lasers ; Swine ; Vaccines, Inactivated ; Vaccines, Virus-Like Particle ; Viral Vaccines

During the coronavirus disease (COVID-19) epidemic, there have been concerns about the impact of vaccines on people's fertility, including the fertility of those who are currently preparing for pregnancy and those who might become pregnant in future. However, there is still a lack of research on the effect of the COVID-19 vaccine on male fertility, and it is not surprising that couples and donors have concerns regarding vaccination. In this study, a retrospective cohort study was conducted to examine semen quality before and after receipt of the inactivated COVID-19 vaccine. There were no statistically significant changes in semen parameters (volume, sperm concentration, progressive motility, and total progressive motile count) after two doses of vaccine (all P > 0.05). In summary, our study updates the most recent studies on the effects of the COVID-19 vaccine on male fertility, and the information from this study could be used to guide fertility recommendations for assisted reproductive technology (ART) patients and donors.
COVID-19 ; COVID-19 Vaccines ; Female ; Humans ; Male ; Pregnancy ; Retrospective Studies ; Semen ; Semen Analysis ; Sperm Count ; Sperm Motility ; Spermatozoa ; Vaccination ; Vaccines, Inactivated

OBJECTIVES: This study aimed to observe the clinical and immune response characteristics of vaccinated persons infected with the delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Yangzhou, China. METHODS: We extracted the medical data of 129 patients with delta-variant infection who were admitted to Northern Jiangsu People's Hospital (Yangzhou, China) between August and September, 2021. The patients were grouped according to the number of vaccine doses received into an unvaccinated group: a one-dose group and a two-dose group. The vaccine used was SARS-CoV-2-inactivated vaccine developed by Sinovac. We retrospectively analyzed the patients' epidemiological, clinical, laboratory, and imaging data. RESULTS: Almost all patients with delta-variant infection in Yangzhou were elderly, and patients with severe/critical illness were over 70 years of age. The rates of severe/critical illness (P=0.006), fever (P=0.025), and dyspnea (P=0.045) were lower in the two-dose group than in the unvaccinated group. Compared to the unvaccinated group, the two-dose group showed significantly higher lymphocyte counts and significantly lower levels of C-reactive protein (CRP), interleukin-6 (IL-6), and D-dimer during hospitalization and a significantly higher positive rate of immunoglobulin G (IgG) antibodies at admission (all P<0.05). The cumulative probabilities of hospital discharge and negative virus conversion were also higher in the two-dose group than in the unvaccinated group (P<0.05). CONCLUSIONS Two doses of the SARS-CoV-2-inactivated vaccine were highly effective at limiting symptomatic disease and reducing immune response, while a single dose did not seem to be effective.
Aged ; Aged, 80 and over ; Humans ; COVID-19/prevention & control* ; COVID-19 Vaccines/adverse effects* ; Critical Illness ; Immunity ; Retrospective Studies ; SARS-CoV-2 ; Vaccines, Inactivated/adverse effects* ; Viral Vaccines/adverse effects*

Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis in Asia and the Western Pacific, which mainly invades central nervous system. Vaccination is the most important strategy to prevent JE. Currently, both live attenuated Japanese encephalitis vaccines (JE-L) and inactivated vaccines (JE-I) are in use. Due to the supply of vaccines and the personal choice of recipients, there will be a demand for interchangeable immunization of these two vaccines. However, relevant research is limited. By reviewing domestic and foreign research evidence, this article summarizes the current situation of the interchangeable use of JE-L and JE-I, and makes recommendations when the interchangeable immunization is in urgent need, so as to provide reference for practical vaccination and policymaking in China.
Encephalitis Virus, Japanese ; Encephalitis, Japanese/prevention & control* ; Humans ; Immunization ; Japanese Encephalitis Vaccines ; Vaccination ; Vaccines, Inactivated