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SINGAPORE researchers have proven that the antiviral drug Tamiflu is not only effective in treating the Influenza A (H1N1) virus, but can also reduce infection when administered in a closed community.
Tamiflu is widely known as an effective H1N1 treatment, but large-scale studies to determine its effectiveness as a preventive tool during a pandemic were unavailable – until Singapore researchers released the study, which was the first in the world.
At a media briefing yesterday, Dr Vernon Lee, the lead researcher of the study and an adjunct assistant professor at the National University of Singapore’s Yong Loo Lin School of Medicine, pointed to how the strategy of ring prophylaxis – the administering of drugs to co-workers of infected patients – “literally stopped the outbreak from spreading”.
From June 22 to 25 last year, when Singaporean military personnel from three units and one camp medical centre were hit by the virus, Tamiflu was administered to 1,100 people.
The results were encouraging: An infection rate of 6.4 per cent, or 75 personnel, dropped to 0.6 per cent, or just seven people, after intervention with Tamiflu. The number of new cases attributable to each initial case also declined significantly, from 1.91 to 0.11.
This means that an infected individual who may have passed the virus to two other people may not infect anyone when Tamiflu is used.
Scientific theories had proposed the benefits of such a strategy, but this is the first real-life documentation of its effectiveness.
The study also showed that the strategy allowed workplace operations to continue undisrupted while substantially reducing the risk of infection.
This is especially significant in closed communities, where there is a high risk of transmission and where the workforce must be maintained, such as in schools, health-care settings and military installations.
The results of the study were published in the New England Journal of Medicine yesterday.
Another researcher on the team, Associate Professor Raymond Tan, noted that vaccines are still the best form of prevention, as vaccinated individuals can be protected for at least a year, but Tamiflu is effective for only as long as it is administered.
The study also noted that the lack of availability of vaccines during a pandemic results in “incomplete global protection”.
And even if vaccines are administered, they take up to two weeks before they start working, while Tamiflu can be used as a post-exposure treatment.
Dr Tan, who is the head of the National Public Health Laboratory at the Health Ministry, said the results of the study put “an option on the cards” in terms of pandemic preparedness planning.
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