NEJM--Safety and Effectiveness of a 2009 H1N1 Vaccine in Beijing

Safety and Effectiveness of a 2009 H1N1 Vaccine in Beijing

Jiang Wu 和 Fujie Xu

Background
After the first monovalent 2009 pandemic influenza A (H1N1) vaccine became available
in September 2009, Chinese officials conducted a mass vaccination program in Beijing.
We evaluated the safety and effectiveness of the vaccine.
Methods
During a 5-day period in September 2009, a total of 95,244 children and adults re-
ceived the PANFLU.1 vaccine (Sinovac Biotech), a monovalent split-virion vaccine of
15 μg of hemagglutinin antigen without adjuvant. We assessed adverse events after
immunization through an enhanced passive-surveillance system and through ac-
tive surveillance, using diary cards and telephone interviews. Active surveillance for
neurologic diseases was implemented in hospitals citywide. To assess vaccine ef-
fectiveness, we compared the rates of reported laboratory-confirmed cases of 2009
H1N1 virus infection in students who received the vaccine with the rates in those
who did not receive the vaccine, starting 2 weeks after the mass vaccination.
Results
As of December 31, 2009, adverse events were reported by 193 vaccine recipients.
Through hospital-based active surveillance, 362 cases of incident neurologic diseases
were identified within 10 weeks after the mass vaccination, including 27 cases of
the Guillain–Barré syndrome. None of the neurologic conditions occurred among
vaccine recipients. From 245 schools, 25,037 students participated in the mass vac-
cination and 244,091 did not. During the period from October 9 through November
15, 2009,  the  incidence of  confirmed  cases of 2009 H1N1  virus  infection per
100,000 students was 35.9 (9 of 25,037) among vaccinated students and 281.4 (687
of 244,091) among unvaccinated students. Thus, the estimated vaccine effectiveness
was 87.3% (95% confidence interval, 75.4 to 93.4).
Conclusions
Among 95,244 children and adults in Beijing, the PANFLU.1 vaccine had a safety
profile similar to those of seasonal inf luenza vaccines and appeared to be effective
against confirmed H1N1 virus infection in school-age children. (Funded by the Bei-
jing Municipal Health Bureau.)

http://www.nejm.org/doi/pdf/10.1056/NEJMoa1006736

疫苗的安全性和有效性评价，的确是一个非常有价值的研究