All people potentially exposed to H5N1 avian influenza in an outbreak in turkeys at a farm in England have been offered antiviral prophylaxis and seasonal flu vaccination to reduce their risk of infection and were told to see their GP if they get symptoms.
Almost 160 000 turkeys have been killed, and movement restrictions have been introduced at a large turkey farm in Suffolk, in southeast England, after some birds were found to be infected with the H5N1 strain.
Maria Zambon, from the Health Protection Agency, a special health authority providing public health advice to the NHS, said farm workers who had come into contact with infected birds and people involved in the culling process were being offered the antiviral drug oseltamivir (Tamiflu) as a precaution. But she stressed that nobody had developed symptoms of bird flu after similar outbreaks in farm birds in continental Europe.
In a statement, the Health Protection Agency said, “Despite this incident the current level of risk to humans from H5N1 remains extremely low. None the less, any possibility of exposure is taken very seriously, and the Health Protection Agency has worked closely with DEFRA [the Department for Environment, Food, and Rural Affairs] and local NHS partners to ensure that all the necessary actions are being taken to protect those people who may have been exposed to the virus.
“These actions include the offering of antiviral drugs and seasonal influenza vaccine where appropriate to people who have been in close contact with the infected poultry.”
The Suffolk office of the Norfolk, Suffolk, and Cambridgeshire Health Protection Unit has been providing antiviral prophylaxis and seasonal flu vaccination to people potentially exposed through working in the infected premises. The virus has so far been detected in only one shed out of 22 at the turkey farm, and 100 of the 2000 staff who work there have been given oseltamivir.
The poultry workers have been asked to contact their GP if they experience fever or respiratory symptoms. In a letter from the Health Protection Agency, GPs have been told to assess patients according to an avian influenza flow chart on the agency's website (www.hpa.org.uk).
GPs have been told to reassure and monitor people who have had direct contact with the affected poultry farm but who do not fit the criteria for avian influenza. The “worried well,” who are concerned but who have had no contact with the farm, should be reassured and told to contact NHS Direct, a telephone helpline, for more advice.
David Nabarro, United Nations coordinator for avian and human influenza, stressed that H5N1 posed little threat to humans. He said, “It is exceedingly unlikely that any human is going to get sick as a result of H5N1 in one turkey farm in Britain at this time.”
He added, “The numbers of human cases are very, very small indeed, even though the virus has been moving through poultry in at least 50 countries in the last year, and led to millions of birds dying. This is really not a human disease, it is a poultry disease.”
The avian flu virus is known to have killed 164 people worldwide—mainly in South East Asia—since 2003. All the people who contracted the virus had come into close contact with infected birds.
The H5N1 virus is most likely to acquire the ability to pass easily from human to human if it mixes with a standard influenza virus and transfers genetic material. To minimise this risk, the Department of Health announced earlier this year that it would offer seasonal flu vaccine to poultry workers throughout England. The theory is that if poultry workers are kept free of normal flu, then even in the highly unlikely event that they were infected with H5N1, the bird flu virus would not come into contact with seasonal flu virus.
Routine reporting on seasonal influenza by the Health Protection Agency showed that for the latest period with figures available (22-28 January) clinical influenza activity remained stable at baseline levels in England (with an influenza-like illness episode rate of 16.8 per 100 000) and Wales, continued to increase in Northern Ireland, and decreased in Scotland.
(See Analysis, doi: 10.1136/bmj.39105.428981.BE.)