Published: 6:17PM GMT 03 Dec 2009
Cases of the H1N1 pandemic virus are dropping but the risk remains that the strain could change into something more virulent, he said.
Sir Liam revealed so-called 'drift' of the virus, where it changes slightly over time, was his biggest worry.
Experts have warned that although the virus is causing only mild illness in the majority of people currently, it could still change into a more dangerous disease.Flu viruses have shown they can mutate easily and they can also mix with other strains raising the concern that swine flu could mix with the more deadly bird flu.
It comes after Tamiflu-resistant swine flu emerged in Wales and spread between very sick patients in a hospital ward. The strain does not appear to have escaped from the hospital and there have been no further cases.
Resistant forms have been found in other countries around the world.
Sir Liam revealed his 'worry list' for the first time, and said: "The biggest worry of all is the fear of mutation. We hear people saying something funny has happened (to the virus) in Norway or France but fortunately we have not seen any change in the virus so far.
"We are not claiming victory, there are still too many things to worry about, particularly at the severe end of the disease spectrum and it is still early days as far as the NHS winter is concerned."
Prof David Salisbury, head of immunisation at the Department of Health, said the vaccines with adjuvants, substances which boost the immune system and allow less active ingredient to be used in each dose, offer good protection even if the virus does change.
The GlaxoSmithKline vaccine, Pandemrix, which forms the bulk of the government programme, contains an adjuvant.
Prof Salisbury said: "One of the advantages with adjuvanted vaccines is their ability to protect against drifted strains. It opens the door for a whole new strategy in dealing with flu."
Sir Liam said his other major concerns were that the NHS could still face severe pressure this winter with ordinary seasonal flu coming after waves of swine flu, other respiratory infections and bad weather combining to stretch the service to it's limits.
And he is worried that there is a 'continuing stream' of children under five in hospital with severe swine flu and complications and that people are still dying from it.
Overall it is estimated there were just 22,000 new cases of swine flu last week, the lowest since the last week of September - near the start of wave two.
There have been 178 deaths in England linked to swine flu and 270 in the UK as a whole, Sir Liam said.
However, despite the drop in new cases, there are still high numbers in hospital, with over 700 patients in wards on Wednesday and 161 of them in critical care, which is only a slight drop on the previous week.
There are now more children under five with swine flu in hospital and in critical care that at any time and they remain the age group hardest hit by the virus.
Sir Liam said the numbers of children in hospital were for suspected swine flu and another virus called respiratory syncytial virus (RSV) which affects children at this time of year annually and has very similar symptoms.
A spokesman for the Health Protection Agency said their data was showing that RSV rates were 'in-line with previous years'.
The vaccination programme is due to be rolled out to children between six months and five years-old once the risk groups have been completed.
So far 11.2 million doses of Pandemrix, the GlaxoSmithKline vaccine, have been sent out to health services, along with 500,000 doses of Celvapan, made by Baxter.
It is estimated 1.6 million doses have been administered to people in the risk groups, including people with long-term conditions and pregnant women.
So far 275,000 doses have been administered to front line health workers in England, more than twice the number of doses of ordinary seasonal flu that were given in the whole of last year.
The figures suggest that front line health workers are not shunning the vaccine as some had feared.
No comments:
Post a Comment