Vaccination coverage survey of children aged 1-3 years in Beijing, China, 2005-2021.

BACKGROUND: The routine immunization program for children is a primary strategy and a core part of vaccination. Achieving and maintaining high level of vaccination coverage are important to reduce morbidity and mortality caused by vaccine-preventable diseases. In Beijing, annual coverage surveys have been conducted since 2005. It is necessary and possible to assess the level and trend of routine vaccination coverage of children in Beijing as well as the disruption of coronavirus disease 2019 (COVID-19) pandemic and provide the reference for the further improve the vaccination coverage. METHODS: The data of 61,521 children aged 1-3 years in the vaccination coverage surveys during 2005-2021 were analyzed by Beijing Center for Disease Control and Prevention. Descriptive epidemiological method was used to analyze the data and the difference of vaccination coverage within the time period. RESULTS: More than 99 % of participants had immunization cards and electronic immunization records. The concordance rate of both records were also over 99 %. During 2011-2019, the rates of on-time and in-time vaccination of each routine vaccine reached 96 % or more and increased significantly (all P values <0.05), compared with that of 2005-2010. All rates of the investigated vaccine, except for Bacillus Calmette-Guérin vaccine (BCG) and the first dose of hepatitis B vaccine (HepB), decreased in 2020-2021 significantly (all P values <0.05). For the causes of failing to vaccinate on time, delayed vaccination accounted for 47.82 %. The top two vaccines to be missed were the first dose of hepatitis A vaccine and the 4th dose of diphtheria-tetanus-acellular pertussis vaccine, accounting for 21.41 % and 20.79 %, respectively. The main reason for zero-dose/drop-out vaccination was "Guardians regarded the immunization service time as inappropriate", accounting for 72.27 %. CONCLUSION: The coverage level and service quality of routine immunization in Beijing were relatively high. However, as influenced by COVID-19 epidemics, both on-time and in-time vaccination rates decreased significantly, except for BCG and HepB. Under the background of COVID-19 pandemic, the keys to maintain high level of vaccination coverage include flexible immunization service time to ensure the guardians bringing their children for vaccination timely, and more attention from providers to the doses after children's first birthday.

[The epidemiological impact of varicella vaccination in kindergartens, primary and secondary schools in Beijing].

OBJECTIVE: To study the epidemiological impact of varicella vaccine vaccination on kindergartens and school children in Beijing. METHODS: According to "China Information System for Diseases Control and Prevention", the reported clinical diagnosis varicella cases were tracked in kindergartens, primary and secondary schools whose onset date were from 2008 to 2010. Epidemiological survey was conducted and epidemiological features were analyzed. RESULTS: A total of 21 474 varicella cases were investigated: 55.3% (11 883 cases) had been vaccinated by varicella vaccine. Of cases with definite immunization history, interval between vaccination date and onset date were from 30 days to 1 year accounted for 3.4% (286/8510), 1 to 3 years accounted for 18.2% (1551/8510), 3 to 5 years accounted for 28.6% (2431/8510), 5 to 10 years accounted for 34.3% (2916/8510) (left-closed right-open interval); The peak age of onset was 4 years old in cases without immunization history, which was 6 years old in cases with immunization history; The proportion of cases with immunization history (≥ 30 days) had increased from 42.4% (2862/6754) in 2008 to 56.3% (4327/7679) in 2010. The cases with no fever had a higher proportion (54.9%, 6413/11 679) of immunization history (≥ 30 days) than cases with fever (47.7%, 4533/9500) (P < 0.01); The cases with rashes less than 50 had a higher proportion (57.4%, 8045/14 020) of immunization history (≥ 30 days) than cases with rashes more than 50 (40.2%, 2902/7216) (P < 0.01). CONCLUSION: Varicella vaccine delays the peak age of onset, alleviates the symptoms. The current immunization strategy can not block varicella spread in kindergartens, primary and secondary schools.

Safety and immunogenicity of two freeze-dried Vero cell rabies vaccines for human use in post-exposure prophylaxis.

To provide basis for human rabies vaccination in China, the safety and immunogenicity of two freeze-dried Vero cell rabies vaccines for human use were assessed. A total of 250 volunteers were enrolled and divided into two groups: volunteers in Group A (n=200) were vaccinated five doses of Speeda Vero cell rabies vaccine manufactured by Liaoning Chengda Biotechnology Co. Ltd. on day 0, 3, 7, 14, 28 after exposure. Volunteers in Group B (n=50) were treated with Verorab Vero cell rabies vaccine manufactured by Sanofi Pasteur on the same schedule. The local and systematic adverse reactions were observed. Serum neutralizing antibody levels of 80 individuals in Group A and 50 individuals in Group B were tested with RFFIT on day 7, 14, 45, 180, 360 after the first dose. The seroconversion rates in Groups A and B were 40.3% and 37.0% on day 7 after the first dose, 95.5% and 97.7% on day 14, 100% and 100% on day 45, 100% and 100% on day 180, 89.1% and 89.5% on day 360 respectively, indicating no significant differences between the two groups. And no significant differences were found between the neutralizing antibody geometric mean titers (GMTs) of the two groups on day 7, 14, 45, 180 and 360 after the first dose, with the GMTs of day 14, 45, 180 and 360 all higher than 0.5IU/ml. Antibody levels of the two groups peaked around 2 weeks after the full vaccination program, followed by a 55% decrease up to day 180 and another 76% decrease up to day 360. Both groups experienced occasions of transient fever, rash, edema, and scleroma after vaccination. Neither group had any severe adverse reactions. It was concluded that both vaccines showed satisfactory safety and immunogenicity. Booster vaccination is recommended following another exposure after six months since the full vaccination program.

[Analysis of adverse events following 2009 influenza A (H1N1) vaccinoprophylaxis in Beijing].

OBJECTIVE: To evaluate the safety of 2009 influenza A (H1N1) vaccine based on mass immunization initiative in Beijing. METHOD: There were 2 113 280 people were vaccinated during September to December 2009. The information of adverse events following immunization (AEFI) was collected through surveillance system, and descriptive methodology was used for data analysis. RESULTS: A Total of 612 AEFI cases were reported, among which there were 321 vaccine reaction cases following immunization, 203 coincidental illness cases, 82 psychogenic reaction cases, and 6 pending cases. The rates of rare reactions and common reactions associated with vaccination were respectively 5.54/100 000 (117/2 113 280) and 9.65/100 000 (204/2 113 280). The rate of serious rare reaction was 0.19/100 000 (4/2 113 280). The rates of vaccine reactions in urban, suburb and county were 16.87/100 000 (36/213 519), 17.81/100 000 (187/1 049 817) and 11.53/100 000 (98/849 944), respectively. The rates of rare reaction and common reaction in different age groups were between 3.65/100 000 (6/164 604) to 8.99/100 000 (27/300 176), and between 0.61/100 000 (1/164 604) to 22.06/100 000 (85/385 275). The 117 rear vaccine reaction cases were mainly allergic reaction (107 cases), and the 204 common vaccine reaction cases were mainly fever (176 cases). There were 91.90% (295/321) vaccine reactions occurred within 24 hours of administration, and all cases had improved consequence. CONCLUSION: The mostly symptoms of AEFI cases during the period of 2009 influenza A (H1N1) vaccinoprophylaxis were anaphylaxis and fever. The types of adverse reactions and the level of serious events are consistent with the anticipation. There were no rear or new events occurred.

[Safety and epidemiological effects of the first China-made mass A (H1N1) influenza vaccination].

OBJECTIVE: To evaluate the safety and epidemiological effects on the first mass vaccination program, using the China-made A (H1N1) influenza vaccine. METHODS: Descriptive epidemiology and cohort study design were used to assess the influenza A H1N1 vaccine on its safety and epidemiological effects. RESULTS: 95 244 subjects were immunized with A (H1N1) influenza vaccine. 193 adverse events were reported through AEFI Management System, with the Reported rates of AEFI as 2.03‰. Most of the adverse events (137/193, 71.0%) happened during the first 24 hours after immunization was carried out. Of 81 adverse reactions confirmed to be related to immunization, with 78 (96.3%) showed mild reactions. No Guillain-Barre Syndrome related to vaccination was reported through the AEFI Management System. The epidemiological protection rate of A (H1N1) vaccine could reach 80.9% when the coverage was not considered. CONCLUSION: The A (H1N1) influenza vaccine showed a similar safety profile to seasonal flu vaccine. The vaccine demonstrated a good epidemiological effects against A (H1N1) influenza virus infection.

[Research progress of H5N1 influenza viruses and the threat to human].

Human, birds and other mammals can be infected by avian influenza A (H5N1) virus. Bird infections spread among continents in the last 2 years. Human infections become endemic in certain areas, characterized with young patients and high mortality. An unprecedented epizootic avian influenza A (H5N1) virus that is highly pathogenic has crossed the species barrier in Asia to cause many human fatalities and poses an increasing pandemic threat. This summary describes the features of human infection with influenza A (H5N1) in epidemiology and etiology and reviews recommendations for prevention.