The role of the Health Protection Agency in the ‘containment’ phase during the first wave of pandemic influenza in England in 2009
When pandemic influenza A H1N1 emerged at the end of April 2009, there was uncertainty about its severity and the impact of the illness associated with it. Some of the initial reports caused considerable concern. It was therefore appropriate for the UK to instigate a robust public health response - Despite extensive pandemic preparedness, countermeasures such as pandemic specific vaccine, were unlikely (and had never been likely) to be available for six months or more. - Measures to attempt to slow the spread of the pandemic in England (labelled ‘containment’), and buy time for the development of countermeasures, were judged to be appropriate. - Through surveillance, monitoring and advice, the Health Protection Agency (HPA) worked with the Civil Contingencies Committee, Department of Health, and National Health Service (NHS) to ensure an informed, effective and coordinated approach. - Containment measures, implemented by the HPA working with the NHS, were demonstrated to be very effective in households, and have some protective effect in other settings in which they were applied. These measures were not expected to prevent the possibility of transmission in the community and, during May and June, an increasing number of cases were identified with no links to other known cases. - Although severe illness, and deaths, occurred in a minority of cases, especially in children and young adults and particularly in those with conditions placing them at high risk of the complications of influenza, most cases experienced a mild illness or no symptoms at all. - During June, mounting evidence of sustained community transmission suggested that the benefit of containment measures was increasingly doubtful, and preparations were made to move to a treatment only approach. - There is insufficient information at present to draw firm conclusions about the effectiveness of the measures taken during the containment phase to slow the spread of infection in the population or to affect the ultimate size of the first wave of the pandemic in England which peaked in late July. - The HPA mounted a substantial sustained and coordinated emergency response throughout the containment period, including the provision of advice to professionals and the public. This phase involved a novel care delivery system for patients with influenza that had not been part of previous planning. The demand placed on the HPA during this period was considerable and HPA resources needed to maintain the containment approach became stretched, particularly towards the end of this phase. - Further detailed review of the effectiveness of the measures taken is warranted when additional information is available. Lessons learnt should be used for future planning.