The Health and Safety Executive has updated its guidance1 on pandemic influenza, including expanded sections on the nature of pandemics, what distinguishes them from ordinary outbreaks and from the much-publicised avian flu, and advice on methods of respiratory personal protection.
Pandemic influenza can occur when a new virus emerges that is markedly different from previously circulating strains, so little or no immunity exists within a population. As a result, the virus infects more people over a wider area, spreads quickly and causes clinical illness in more of those infected. Around a quarter of the population would become ill during a UK pandemic, with another 25% catching the infection without getting any symptoms.
Avian influenza is a disease of birds, and humans are only rarely infected by “bird ‘flu”, usually as a result of particularly close contact with infected stock. The two types of influenza are confused by the media and the public because the current avian influenza virus strain (H5N1) has the potential to mutate or recombine genetically with the human influenza virus to create a new pandemic human strain.
The revised HSE guidance includes a series of “frequently asked questions” including, for example: “Do my employees need to wear masks” and “What about workers who regularly come into contact with the public?” The guidance makes it clear that employees with influenza-like symptoms should stay away from work, making it unnecessary in most cases for other employees to wear masks at work. However, there may be some situations when it is advisable for workers to wear masks for example, if they are likely to encounter members of the public with symptoms, and where the duration and frequency of this contact is relatively high.
The guidance details the types of mask available, and the differences between plain surgical masks and filtering face piece 3 (FFP3) masks. The latter provide high levels of filtering capability and face fit and can be supplied with an exhale valve so they are able to be worn over a long period of time. However, this type of mask needs to be selected with care to ensure a good fit around the nose and mouth. HSE guidance recommends that FFP3 masks are fit-tested in advance, and that more than one make of mask is available as one may prove a better fit for some people than others.
The guidance stresses that pandemic influenza is primarily a public health matter. However, there are health and safety obligations on employers (under the COSHH Regulations, for example) in the case of workers who might come into contact with infectious micro-organisms, either directly as part of their work as researchers or in the healthcare sector.
1 Pandemic flu – workplace guidance, April 2008