A strain of swine flu resistant to the anti-viral drug Tamiflu is spreading from person to person, health officials in Wales confirmed last night
Five patients on a unit treating those with severe underlying health conditions at the University Hospital of Wales, Cardiff, have been diagnosed with the resistant strain. Three appear to have acquired the infection in hospital, the National Public Health Service (NPHS) for Wales said.
The cases are believed to be the first in the world in which person-to-person transmission of a Tamiflu-resistant strain has been confirmed. Although there have been sporadic reports of Tamiflu resistance around the world, there has only been one reported case of person-to-person transmission – between two people at a US summer camp – that has never been confirmed.
Dr Roland Salmon, director of the NPHS Communicable Disease Surveillance Centre, said: "The emergence of [the Tamiflu-resistant strain] is not unexpected in patients with serious underlying conditions and suppressed immune systems, who still test positive for the virus despite treatment. In this case, the resistant strain of swine flu does not appear to be any more severe than the swine flu virus that has been circulating since April."
The five patients have been isolated and are being treated with an alternative antiviral drug "in a designated area for influenza cases", the NPHS said.
The chief medical officer for Wales, Tony Jewell, said: "Treatment with Tamiflu is still appropriate for swine flu and people should continue to take Tamiflu when they are prescribed it." The Department of Health said it was taking the development seriously but that the risk to the healthy population was "low".
Tamiflu, made by Roche, is the first line of defence against swine flu and the Government has stockpiled enough doses for half the population. Taken within 48 hours of the onset of symptoms, the drug can lessen the severity of the illness, as well as shortening its duration, and has been credited with saving lives, especially those of vulnerable patients with chronic illnesses.
Doctors feared that its widespread use would lead to the development of resistant strains of swine flu, and some have argued that it should be restricted to avoid that outcome. The spread of a Tamiflu-resistant strain of the illness would be a serious public health concern.
A Department of Health spokesman said: "The Tamiflu-resistant virus has emerged in a group of particularly vulnerable individuals – this type of resistance is well documented. In other words, these patients are known to be at increased risk of developing resistance to the drug. Our strategy to offer antivirals to all patients with swine flu is the right one – both to help prevent complications and to reduce the severity of the illness. We are keeping the situation under review."