The importance of school and social activities in the transmission of influenza A(H1N1)v: England, April – June 2009

Abstract

During the containment phase in the United Kingdom (April to June 2009), a cluster of influenza A(H1N1)v cases was identified prompting further investigation and public health action by the Health Protection Agency. The first confirmed case, a pupil at a school in England, was imported. During the following two weeks, 16 further cases were confirmed with epidemiological links to the first imported case. In this cluster, we found that significant transmission occurred in two classes with attack rates of 17% and 7%. In each of the two classes a case had attended school whilst symptomatic. Other settings included a party and a choir. Minimum and maximum attack rates were 14% and 25% for the party. For the choir both the minimum and the maximum attack rate was 4%. We did not find any evidence of transmission on two school bus trips despite exposure over 50 minutes to a symptomatic case and over two periods of 30 minutes to a case during the prodromal phase (i.e. within 12 hours of symptom onset). Nor was there onward transmission in another school despite exposure over several hours to two cases, both of whom attended school during the prodromal phase.

Serologic survey of pandemic influenza A (H1N1 2009) in Beijing, China

“…Stratification based on whether the subjects' family included students attending school at that period showed an increase in the pandemic H1N1 infection rate in the families that had school children. This clearly suggested that school children should be one of the key target populations for vaccination to pursue infection control, and this view is shared by an English research group, which highlighted the importance in protecting school children during the pandemic (Kar-Purkayastha et al, 2009). Our data also show that medical personnel with asymptomatic infection with pandemic H1N1 may be a risk factor for hospital-onset infection in Beijing.…”

Reconstruction of epidemic curves for pandemic influenza A (H1N1) 2009 at city and sub-city levels

“…This may be explained by the differential pattern of virus transmissions in each region in view of the variation of population structures, or that there were higher uptake of reported cases in some locations against the background of considerable public attention, when the news of an impending epidemic first broke out[7]. On the other hand, the landscape of the epidemic curve thus constructed was contributed largely by infections in students, an observation made in other studies on pandemic (H1N1) as well as seasonal influenza[8,9]. Against the background of a relatively uniform physical and climatic environment within Hong Kong, the temporo-spatial variability of influenza spread could only be explained by the heterogeneous population structure and mobility patterns.…”

H1N1 outbreak in a medical college of Pakistan: Implications of control in a resource poor setting

“…An interesting observation was that the outbreak occurred in November as opposed to April to June as noted in other reports. [4][5][6][9][10][11] An outbreak was noted in Saudi Arabia in the month of October as well.…”