Tamiflu-resistant swine flu spreads 'between patients'

Health officials say a Tamiflu-resistant strain of swine flu has spread between hospital patients.

 

Five patients on a unit treating people with severe underlying health conditions at the University Hospital of Wales, Cardiff, were infected.  Three appear to have acquired the infection in hospital.
They are thought to be the first confirmed cases of person-to-person transmission of a Tamiflu-resistant strain in the world.  There have been several dozen reports around the world of people developing resistance to Tamiflu while taking the drug - but they have not passed on the strain to others.
Just one possible case of person-to-person transmission of a resistant strain has been recorded - between two people at a US summer camp - and this has never been confirmed.

Two of the University Hospital of Wales patients have recovered and have been discharged from hospital; one is in critical care and two are being treated on the ward.  The health officials stressed there was no risk to anyone else.  They said tests were being carried out to confirm exactly what happened.
The UK has bought enough doses of Tamiflu, which can shorten the duration of swine flu and reduce the risk of complications, for half the population.

Serious concern

So any spread of a Tamiflu-resistant strain of the illness is a serious public health concern.
The H1N1 virus has been remarkably stable since it emerged in April, but virologists had been half expecting new resistant strains to emerge.  Dr Roland Salmon, director of the National Public Health Service for Wales' Communicable Disease Surveillance Centre, said: "The emergence of influenza A viruses that are resistant to Tamiflu 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."  Dr Tony Jewell, Chief Medical Officer for Wales, said: "We know that people with suppressed immune systems are more susceptible to the swine flu virus, which is why they are a priority group under the first phase of the vaccination programme in Wales which is progressing at pace.  "We have stringent processes in place for monitoring for antiviral resistance in the UK so that we can spot resistance early and the causes can be investigated and the cases managed.
"Identifying these cases shows that our systems are working so patients should be reassured.
"Treatment with Tamiflu is still appropriate for swine flu and people should continue to take Tamiflu when they are prescribed it.  "It's also important that good hygiene practices are followed to further prevent the spread of the virus."

Professor Peter Openshaw, a respiratory physician at Imperial College London, said of the spread: "It's not surprising that this has happened, indeed it has always been anticipated".  Dr Ronald Cutler, deputy director of biomedical science at Queen Mary, University of London, said: "Shortening the time taken to produce new vaccines and improving the methods to control and treat the disease while vaccines are being made would be a way forward".  On Thursday it was announced that more than three million healthy children under five across the UK will be offered the swine flu jab.  Figures released on Thursday showed an estimated 53,000 new cases of swine flu in England in the last week, down from 64,000 in the week before.  In Scotland, the figure was 21,200, down from about 21,500 in the previous seven days.
The rate of flu-like illnesses diagnosed by GPs in Wales dropped to 36 cases for every 100,000 people from 65.8 the previous week.

By Fergus Walsh
Health correspondent, BBC News

DRUG RESISTANT FLU WARNING

Australian experts are concerned about the threat of a new type of drug-resistant pandemic flu that is circulating in the population at large.  The swine flu strain has learned how to dodge the antiviral Tamiflu and, though rare, is emerging outside of hospitals.  The team who have studied it say the virus is "fitter" than other drug-resistant strains and the world should be on alert for outbreaks.

UK experts say they have seen a handful of similar cases.  The UK's Health Protection Agency said it would be closely monitoring the situation.  The Australian investigators presented their findings at a meeting on major infectious diseases.

Swine flu

• H1N1 caused a swine flu pandemic (an extensive outbreak in many countries) in 2009 infecting a fifth of the population
• Many people now have some immunity to H1N1 as a result of this exposure
• Vaccines are available that can stop H1N1 infections
• Some people - the sick, elderly, young infants and pregnant women - are at particular risk of complications of they catch H1N1
• Antiviral drugs like Tamiflu can lessen the severity of symptoms in those who catch H1N1

Experts at the Annual Scientific Meeting of the Australasian Society for Infectious Diseases heard how the 'H1N1pdm09' swine flu virus is still sensitive to another antiviral drug Relenza (zanamivir).

But Tamiflu (oseltamivir) is now powerless against the strain that has been found in people in the community rather than sick patients with serious underlying conditions and weak immune systems.
Vaccines can prevent infection occurring in the first place.

Lead investigator Dr Aeron Hurt, from the World Health Organization Collaborating Centre for Reference and Research on Influenza in Melbourne, said: "The greatest concern is that these resistant viruses could spread globally, similar to that seen in 2008 when the former seasonal H1N1 virus developed oseltamivir resistance and spread worldwide in less than 12 months."
The new strain that they have been examining is emerging among people who have never been treated with Tamiflu, suggesting it is very good at spreading from person to person.
Dr Hurt says animal studies by his team confirm this.  Although the Tamiflu-resistant strain is still relatively rare, affecting about 2% of people with swine flu in the Australian population that they studied, Dr Hurt is concerned that it has the potential to turn global.  Similar resistant strains have been detected in Europe but at this stage only on an ad hoc basis, says Dr Hurt.  "The widespread transmission and circulation of oseltamivir-resistant H1N1pdm09 viruses remains a risk in the future.  "Close monitoring of resistant viruses in both treated and community patients remains important."

Pandemic potential In the UK, the HPA has recorded eight cases of oseltamivir-resistant H1N1pdm09 in the community setting.  The HPA's head of flu surveillance Dr Richard Pebody said: "While the frequency of oseltamivir resistance in community settings has increased slightly since the 2009-10 pandemic from 1-2% in the 2012/13 flu season, rates of detection remain low."  Swine flu (H1N1) infected a fifth of people during the first year of the pandemic in 2009, data suggest.
It is thought the virus killed 200,000 people globally.  Although the pandemic has been declared by officials as over, the virus is still circulating.  During the pandemic, the H1N1 virus crowded out other influenza viruses to become the dominant virus. This is no longer the case. Many countries are reporting a mix of influenza viruses.

Sourced from www.bbc.com