a cohort sample of 18- to 60-year - old adults in hong kong participated in 7 rounds of telephone surveys during august 2009july 2010 , which covered almost the entire ph1n1 pandemic period in hong kong . at baseline , we invited 677 adults to participate ; 503 ( 74.3% ) consented and completed the survey ( technical appendix table 1 ) . we measured the following variables : knowledge about the modes of ph1n1 virus transmission ; risk perceptions associated with the virus ( perceived susceptibility to and severity of infection ) ; perceived efficacy and use of preventive measures ( e.g. , handwashing , using a facemask ) ; psychological responses ( worry about infection and emotional distress ) ; and evaluations of the government s performance in pandemic control . sample sizes for surveys 27 ranged from 452 to 481 , yielding retention rates of 89.8%95.6% . most participants were women ( 57.9% ) , 4060 years of age ( 55.8% ) , employed full time ( 55.9% ) , and married ( 65% ) . sex and age distributions were comparable to those in the local census data ( 6 ) . we aimed to determine whether there were overall linear trends in participants perceptions , psychological responses , and behavioral responses to the pandemic . we examined linear trends for these variables across the 7 time points by using generalized estimating equations ( gee ) models . gee models not only account for intracorrelated repeated measures data but also fit various data types using appropriate link functions . the analyses were conducted using proc genmod ( sas institute , cary , nc , usa ) ; 2-sided p<0.05 was considered significant . over time , > 85% of the participants used a face mask and immediately visited a doctor when experiencing influenza - like symptoms . more than 50% of the participants washed their hands > 10 times every day throughout the survey period ( p>0.05 ) . as the pandemic progressed , a decreasing percentage of participants wore masks in public areas ; avoided touching their mouth , nose , and eyes ; took antiviral drugs ; and avoided crowded places ( p<0.001 ) ( technical appendix table 2 ) . percentages of participants feeling worried , depressed , or emotionally disturbed about ph1n1 virus decreased over time ( p<0.001 ) ( technical appendix table 3 ) . over time , a decreasing percentage of participants recognized that touching infected persons or contaminated objects could result in virus transmission ( p<0.001 ) . throughout the study period , a consistently high percentage of participants ( > 92% ) recognized that the virus could be transmitted via respiratory droplets . misconceptions about possible transmission through insect bites ( 26.1% ) and water sources ( 34.5% ) were prevalent . the percentage of participants reporting at least 1 misconception was stable over time ( p>0.05 ) . a consistently high percentage ( > 90% ) of participants believed that using face masks in public areas , washing hands frequently , and avoiding crowded places could effectively prevent the spread of ph1n1 virus ( p>0.05 ) . the percentage of participants believing that ph1n1 virus would be more harmful than seasonal influenza in terms of fatality and bodily damage increased over time ( p<0.001 ) . the percentages of participants who believed the population was highly susceptible to ph1n1virus infection and who perceived a high chance of having a large - scale local outbreak in the coming year dropped significantly ( p<0.001 ) , but some fluctuations were observed ; for example , the percentage peaked during survey round 2 ( around the september influenza season ) . throughout the study period , 12%21% of the participants gave a failing score ( < 5 on a 0- to 10-point scale ) for the government s overall performance in controlling the pandemic ( p>0.05 ) . however , during survey rounds 27 , an increasing percentage of participants believed in the government s ability to control the pandemic ( p<0.001 ) ( online technical appendix ) . the percentage of participants who believed that hong kong would not have enough vaccine or medication to deal with the pandemic decreased over time ( p<0.001 ) . this study investigated changes in community perceptions over the course of the ph1n1 pandemic in hong kong . findings were highly comparable to those from other local cross - sectional surveys ( 5,7 ) and a systematic review ( 8) . knowledge regarding preventive measures and adherence to such measures was , in general , higher among our participants than among the general population in other countries ( e.g. , australia , india , and the netherlands ) ( 911 ) . the prevalence of misconceptions about some incorrect modes of transmission ( e.g. , insect bites ) gradually declined . however , 50% of participants still held at least 1 of the 4 misconceptions regarding transmission ( i.e. , airborne transmission over a long distance and transmission through insect bites , water sources , and well - cooked pork ) . furthermore , over time , a lower percentage of participants avoided touching their eyes , nose , and mouth to prevent virus transmission . a 2015 systematic review suggested that health authorities should provide more updated information about the virus ( 8) . we also recommend using health campaigns to increase public awareness about different routes of ph1n1 virus transmission . perceived severity of ph1n1 virus infection decreased over time , which may partially explain the decline in distress and avoidance behaviors ; this pattern was also observed in a recent review ( 8) . however , an increasing proportion of participants believed that , compared with seasonal influenza , ph1n1 resulted in more deaths and more severe body damage . perceived susceptibility to infection declined substantially as the epidemic progressed , suggesting that the public gradually perceived fewer risks from ph1n1 virus . avoidance behaviors and use of facemasks in the absence of influenza - like symptoms became less prevalent over time , similar to a trend seen in malaysia ( 12 ) . mental distress among persons in hong kong was lower during the ph1n1 pandemic than during the sars ( severe acute respiratory syndrome ) pandemic ( 13 ) , possibly due to the milder consequences of ph1n1 infection . persons in hong kong seemed to remain rational during the pandemic , thereby avoiding possible pandemic - associated economic threats . public support for the government declined over time . during survey round 5 , a total of 20.6% of the participants gave a failing score to the government s performance , and 13.5% perceived that the government would not be able to control the pandemic . the poll was split as to whether the government should use the same response for ph1n1 influenza and seasonal influenza . our findings suggest that the public should be advised of the pros and cons of ph1n1 control policies ; a watchful step - down may be better accepted if the policies are understood . however , participants demographics were comparable to those in local census data ( 6 ) . second , hong kong s unique experience with the sars outbreak may have influenced the population s response to the ph1n1 pandemic ; thus , our findings may not be fully generalizable to other countries . ideally , polynomials should be added to the linear time variable ; however , given the small number of time points and absence of theoretical shapes , that was not feasible . our findings provide valuable information regarding overall linear trends and changes in community responses toward the ph1n1 pandemic among a hong kong cohort . these findings should help inform other countries in formulating appropriate pandemic control plans for influenza and other emerging infectious diseases . detailed methodology and findings for a study of population responses during the pandemic phase of the influenza a(h1n1)pdm09 epidemic , hong kong , china .
during august 2009july 2010 , we conducted 7 longitudinal telephone surveys among 503 adults in hong kong , china , to explore changes in their behavioral and psychological responses to the influenza a(h1n1)pdm09 virus epidemic . 
 trends were examined using generalized estimating equations models . 
 findings showed that responses varied with the course of the pandemic .