BACKGROUND: A novel avian influenza A(H7N9) virus, first identified in Mainland China in February and March 2013, caused an outbreak in humans in April and May, 2013. Closure of live poultry markets in some affected cities dramatically reduced numbers of cases during summer of 2013, but the epidemic resurged during the winter 2013–14, increasing reported cases to 393 in Mainland China as of 30 March 2014. PURPOSE: The study aimed to explore population behavior patterns responding to an epidemic of influenza A(H7N9) virus. METHOD: Three cross-sectional surveys were conducted among 1000, 680, and 1011 respondents in December 2013, January 2014, and February 2014, with response rates of 68.0, 64.4, and 66.6 %, respectively, in Hong Kong. Adults were recruited and interviewed using random digit-dialing telephone survey. Latent class analysis was employed to explore heterogeneity in protective behavior patterns across the three surveys. Multinomial regression models were developed to determine factors associated with latent class membership. RESULTS: Three comparable latent classes were identified across the three surveys: Moderate hygiene compliance (Class 1), High hygiene compliance (Class 2), and Vigilance (Class 3). The prevalence of Class 1 was 48–52 % across the three surveys while Class 3 prevalence increased significantly from 13 % in the Dec-2013 survey to 20 % in the Feb-2014 survey. Compared with Class 1, Class 3 were more likely to be female, older, better educated, married, perceive higher susceptibility to H7N9, attribute greater severity to H7N9, report higher current worry, and anticipated worry about H7N9 infection. CONCLUSION: The three classes reflect different levels of adoption of protection and thereby may have different levels of vulnerability toward contracting H7N9 infection. It appears that as the epidemic intensifies, Class 2 (Good hygiene compliance) members are likely to transfer to Class 3 (Vigilance) while Class 1 (Moderate hygiene compliance) could be unchanged. The young, mostly single males and those with lower educational achievement represent a group for whom public health messages need to be targeted.
Population Behavior Patterns in Response to the Risk of Influenza A(H7N9) in Hong Kong, December 2013–February 2014