Following WHO recommendations in 2005, various countries developed or revised preparedness plans for pandemic influenza.1 The advent of the novel influenza A virus subtype H1N1 ('swine flu') has seen these countries review and implement their pandemic plans including vaccination strategies, where healthcare workers are a priority group for mass vaccination The unknown factor is the level of acceptance for pre-pandemic vaccination against swine flu.

Two surveys conducted in Jan-Mar 2009 and May 2009, and involving healthcare workers in public hospitals in Hong Kong, found low levels of willingness to accept vaccination against both influenza A virus subtypes H1N1 and H5N1.1 The overall level of willingness to accept pre-pandemic H5N1 vaccination was 28.4% in the first survey - at a time when the WHO influenza pandemic alert level was at phase 3 - and 34.8% in the second survey (WHO alert level at phase 5). The overall level of willingness to accept pre-pandemic H1N1 vaccination was 47.9% and was determined when the WHO alert level was at phase 5. Survey responses identified fear of adverse effects and uncertainty over vaccine efficacy as barriers to acceptance.

To V or not to V

With the expectation that a swine flu vaccine will be ready and licensed by October 2009, the focus becomes one of prioritisation, with frontline healthcare workers among the first to be offered vaccination.2 But in light of the Hong Kong survey results, will they accept?2

The evidence is mixed. Over 75% of healthcare workers in Leicester, UK, indicated a willingness to accept a pandemic vaccine; however, the survey was conducted when the H5N1 subtype was the main risk (high case fatality rate) rather than the H1N1 subtype (relatively low mortality).2 A recent online poll of frontline nurses indicates that around 37% of respondents intend to be vaccinated, 33% were undecided and 30% did not want to be vaccinated. Reasons for nonacceptance of a pandemic vaccine included safety and efficacy concerns and a low perceived pandemic threat. It is interesting to note that uptake of seasonal influenza vaccination among healthcare workers is typically low.2

In a BMJ editorial Rachel Jordan and Andrew Hayward argue that while there are many uncertainties in a pandemic, “without vaccination many healthcare workers will become infected”.2 Vaccination will help “keep the healthcare system operating at maximum capacity throughout the pandemic”.

Key words

Influenza-A-virus-H1N1-vaccines - therapeutic use - prevention - Research-and-development - Influenza-A-virus-H1N1-subtype - Patient-compliance