06 Jul 2009
Government's announcement that the UK is moving to a new phase in the response to the current pandemic flu virus means there will be a change to the surveillance information that the Health Protection Agency will be able to provide to the media in future.
The Agency has been carrying out laboratory testing of suspected cases of pandemic flu (H1N1v) since the outbreak came to light in April. The Agency's daily update has been based, since then, on the number of positive test results being confirmed through the Centre for Infections and the Agency's regional network of laboratories.
The new policy moves from measures to try and contain the pandemic flu virus to focussing on providing appropriate treatment to people with H1N1v flu. This means that, nationally, clinicians will now rely on patients' symptoms rather than laboratory tests to diagnose illness. Although we will continue to test a proportion of patients to ensure we keep getting up to date information about the virus, the daily reporting of laboratory confirmations will no longer be an accurate way to record the spread of infection, as it will not include the vast majority of cases.
The HPA will, therefore, no longer be providing a daily update of the numbers of cases confirmed through laboratory tests. From next week, the Health Protection Agency's Centre for Infections press office will instead issue a weekly media alert covering the various surveillance systems the Agency will be using to monitor the ongoing situation. This will also be available in the News section of the Agency's website at http://www.hpa.org.uk. The exact day these new weekly alerts will start will be confirmed next week.
This country has well established, and internationally respected, surveillance systems for monitoring the levels and impact of flu, which have operated through the 'normal flu season' over the last few years. These systems have proved effective for informing policy and planning and are included in existing pandemic preparedness plans as central to surveillance in a pandemic situation.
These existing systems will be augmented by additional surveillance activities, relevant to the H1N1 pandemic situation, that will continually assess the severity of disease associated with this novel virus and monitor changes in the characteristics of the virus.
The approach to surveillance in this new treatment phase will not provide a definitive figure of the number of cases nationally or regionally at any one time, as this will no longer be possible when widespread laboratory testing ceases. Instead, the updates will be providing a variety of indicators of overall flu activity in the population (i.e. aggregate measures of rates of illness). This will be supported by sample-based surveillance to detect and monitor particular characteristics of the virus or the illness that it causes. This is broadly the same approach as is taken to monitoring seasonal flu. This surveillance will provide:
- The collection of data from a network of GP surgeries across the country which provide consultation rates for patients presenting with flu-like illness.
- A 'syndromic surveillance' system, operated by NHS Direct in collaboration with HPA, which provides information on numbers of callers reporting cold/ flu symptoms and fever.
- Data from sample laboratory testing of some patients from community and hospital sources, providing information on the flu virus types circulating in the community.
The Agency has used this set of very comprehensive surveillance mechanisms over many flu seasons to accurately predict flu levels, monitor new and emerging viruses and identify trends in activity. This experience means we can confidently continue to monitor the incidence and distribution of this pandemic virus over the summer and beyond. The agency remains committed to keeping people up to date with the current situation on swine flu.
Further information on swine flu is available on the Health Protection Agency's website at http://www.hpa.org.uk/swineflu.
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