Cracking the influenza puzzle

Australian researchers have discovered that the antiviral drug, Tamiflu, is effective in preventing and treating influenza outbreaks in aged care facilities.

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By Yasmin Noone

Australian researchers have cracked part of the influenza puzzle, with new trial results now proving that the antiviral drug, Tamiflu, can effectively treat and prevent outbreaks in aged care facilities.

The landmark University of Sydney trial, whose results appeared in PLOS One today, offers a new preventative approach to managing and preventing influenza outbreaks in aged care facilities throughout Australia and the world.  

The trial shows that prescribing the antiviral drug, oseltamivir – commonly known as Tamiflu – following an influenza outbreak in a nursing home will lower the rate of infection in residents and staff, reduce related-hospitalisations and decrease the duration of the outbreak.

Team geriatrician from Sydney Medical School and The George Institute, Professor Richard Lindley, said the trial results have far-reaching international benefits.

In developed countries, people over 65 years old are the most likely to die from an influenza outbreak and people in nursing homes, where the virus is difficult to control, are especially vulnerable.

“This is a landmark trial as it has found an effective treatment for some of the most disadvantaged people in our community, who are usually excluded from major studies of this kind,” said Prof Lindley.

“The speed and virulence with which influenza spreads in aged care homes is a recognised health issue so reducing both the numbers of people infected and the duration of the outbreak is a major breakthrough.”

The study, he said, confirms the value of Tamiflu as a treatment for influenza.

“We found that something [the use of Tamiflu] that has been creping into guidelines really does work.

“It’s interesting that the public health departments have started using Tamiflu as an emergency extreme measure for a flu outbreak, if it got out of control, but there was no evidence that that is an effective policy.”

That is, up until now, he added.

This trail provides evidence on how aged care facilities can manage a respitatory outbreak.

” You need to do some tests, involve GPs and local public health departments early, pay scrupulous attention to infection control, and if you confirm an outbreak, we now have a [proven] intervention that is effective.

“…Influenza is a nasty illness to have so we hope these trial results will help improve the quality of life of frail older people.”

Head of clinical research at the National Centre for Immunisation Research and Surveillance at Sydney Medical School, and lead researcher, Professor Robert Booy, said the study’s findings are important  public health results.

“Influenza causes untold misery and is frequently fatal for older people,” Prof Booy said.

“These results provide good evidence to support an active policy of treating and preventing influenza promptly, once an outbreak is declared.”

Three seasons, 16 facilities

The trial took place in 16 aged care facilities throughout the Sydney area over three winter flu seasons.

The research team used Tamiflu via two different strategies when an outbreak occurred: they either treated only those residents in the home who had influenza symptoms with Tamiflu or they treated all residents with Tamiflu.

When treating everyone, Tamiflu was being used both as a treatment and a preventive health measure.

The results of treated patients showed a reduction in the length of the influenza outbreak by 13 days and a reduction in the numbers of residents infected by a statistically significant amount (36.5 percent among those treated only for symptoms compared to 22.9 percent for those given the preventive treatment);

Their results support the policy of widespread preventive use of the drug during outbreaks.

“Getting any flu outbreak under control quickly is really important as it quickly spreads into the local community from bad outbreaks in nursing homes and schools,” said Professor Dominic Dwyer, the team virologist from Sydney Medical School and Westmead Hospital.

During the study period, the researchers monitored for any evidence of an outbreak and 23 respiratory illness outbreaks were detected of which nine were shown to be influenza.

According to Prof Lindley, “if GPs assume [symptoms] are influenza and are dishing out Tamiflu, they’d be wrong the majority of the time”.

“It’s important because if people use Tamiflu for treatment and use it too much, that might create resistance.”

Prof Lindley said although conducting the trial came with challenges, he and the team are pleased to have completed it as it discovered “what works for frail older people”.

“I hope it encourages other researchers to take on other questions [relating to] the care of frail elderly people.”

Tags: flu, influenza, of, outbreak, sydney, tamiflu, university,

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