P2-429 Prevalence of influenza A (H1N1) seropositivity in unvaccinated healthcare workers in Scotland at the height of the global pandemic

K. Smith, L. Williams, W. Adamson, S. V. Katikireddi, P. Dewart, E. Fletcher, W. Carman, K. Templeton, F. Denison, P. Warner, D. G. Mackenzie

Research output: Contribution to journalMeeting abstract


Introduction Susceptibility of healthcare workers (HCW) to influenza is relevant in terms of sickness absence, productivity and onward transmission of infection from carer to patient, a particular issue with a novel influenza strain. The aim of this study was to determine the seroprevalence of antibodies against the virus in unvaccinated healthcare workers in Lothian, south east Scotland during October- November 2009 (after the first wave of infection, but before the expected increase in cases over the winter period).

Methods Unvaccinated employees (n=493) were recruited within days of the start date of the HCW vaccination programme and prior to most being vaccinated. Participants had a serum sample taken and completed a short questionnaire recording sex, age, occupation, and self-reported history of flu-like symptoms or illness since the start of the pandemic period. Serology specimens were analysed in the West of Scotland Specialist Virology Centre in Glasgow using microneutralisation assays at a dilution of 1:40.

Results The prevalence of seropositivity in HCWs mid-pandemic was 10.3% (95% CI 7.7 to 13.0%), which was higher than pre-pandemic HCW seropositivity rate by 3.7% (95% CI of increase 0.3% to 7.3%, p=0.048). Seropositivity rates for frontline and non-frontline HCWs were similar.

Conclusion To our knowledge, this is the first study in the United Kingdom to quantify the level of seropositivity to influenza A(H1N1) in unvaccinated HCWs pre- and mid-pandemic. Only 10.3% of HCWs were seropositive for influenza A(H1N1) mid-pandemic, so the great majority were still susceptible to infection at the introduction of the vaccination programme.
Original languageEnglish
Pages (from-to)A340-A340
Number of pages1
JournalJournal of Epidemiology & Community Health
Issue numberSuppl 1
Publication statusPublished - Aug 2011


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