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Still more questions than answers

Fergus Walsh | 08:38 UK time, Thursday, 12 November 2009

Influenza viruses have been causing sickness for thousands of years so it may seem curious that there is still a huge amount that we don't understand about them.

This applies especially to H1N1 swine flu which, admittedly, has only been circulating in humans for a matter of months.

A series of research projects in the UK have been announced which will examine every aspect of the swine flu virus - in pig and human populations, and in hospital intensive care units.

£7.5 million pounds of funding has been given by the Medical Research Council (MRC), Wellcome Trust, and Biotechnology and Biological Sciences Research Council (BBSRC) along with some government support.

The research will aim to answer many of the questions which commenters on this blog have raised, and more besides:

• Why do some people and not others become seriously ill with swine flu?
• What proportion of people who are infected have no symptoms (what's known as asymptomatic)?
• If you are asymptomatic, can you still spread flu?
• How useful are antivirals?
• How effective is the vaccine?
• How does H1N1 swine flu behave in pigs?
• Is there a risk that the virus could evolve into a more virulent form in pigs?
• Is there a need for a vaccine for pigs to slow the spread of the virus?


A study led by Dr Andrew Hayward of University College London, which will follow up to 10,000 people and look at the duration and severity of symptoms, their access to treatment, use of antivirals and uptake of the vaccine.

We should not have to wait long for results. Dr Hayward said he hoped to release initial data before Christmas.

This study should help scientists work out what proportion of the population has had swine flu. This is crucial because at present we have only tenuous estimates from the Health Protection Agency which are subject to a huge margin of error.

Last week's estimated cumulative number of cases was 620,000 in England (with a range from 289,000 to 1,278,000).

The reason we don't have a clear idea of how many people are infected is because the majority of those who get flu, never go anywhere near the health service and only the sickest patients get tested for the virus.

If we knew what proportion had no symptoms or recovered without bothering their doctor, it would help us understand how quickly we may get through this pandemic.

It will also look at how effective antivirals have been in treating flu - a hot topic for months. Some have criticised the policy here of offering Tamiflu to anyone who says they have flu-like symptoms.

Dr Fred Hayden from the Wellcome Trust (Professor of Medicine at the University of Virginia) pointed to a study in the New England Journal of Medicine last month. This looked at nearly 300 patients admitted to hospital in the United States.

Dr Hayden said:

"[F]or those admitted to hospital, the average time they waited before getting antivirals was three days, for those admitted to intensive care it was six days and for those who died it was eight days."

He said that early treatment, even in uncomplicated seasonal flu, could reduce the risk of complications.

The Mechanisms of Severe Acute Influenza Consortium (MOSAIC)

Thankfully the principal investigator, Professor Peter Openshaw from Imperial College London, came up with the snappy acronym MOSAIC.

A team of scientists from England and Scotland will look at up to 500 people hospitalised with flu during the pandemic and try to find out what factors contributed to the severity of their disease.

For example, was there something about their genetic make-up which made them more susceptible to the virus, or was it due to variations in the virus itself?

They'll be taking around 40 samples from each volunteer and doing extensive virology and bacterial work in several UK labs.

This study will take about a year to complete and, like the others, could yield useful information for future pandemics.

Combating Swine Influenza (COSI) Initiative

There are two studies here looking at the evolution and spread of pandemic H1N1 virus in pigs and how to develop ways to slow the spread of the virus in animals and humans.

The research will be led by Professor James Wood at the University of Cambridge and Professor Ian Brown at the Veterinary Laboratories agency at Weybridge.

Professor Wood said that for the last 10 years scientists had concentrated more on avian influenza and there was a lack of detailed surveillance in pigs.

"It's important we understand the evolution of the H1N1 pandemic" he said. "We need to look at where it came from and how it's evolving. It's possible that it may take a different evolutionary course in pigs and pose a different threat to humans."

He pointed out that farmers had passed the H1N1 pandemic virus to pigs in Argentina, Australia, the USA and Canada.

One issue that has been puzzling me is why the pandemic virus is currently so stable. We are always told that RNA viruses like flu have a high mutation rate. It's why people need a flu jab each autumn.

Professor Wendy Barclay, virologist at Imperial College London said there was genuine uncertainty about the H1N1 swine flu virus: "We don't know why it's so stable" she said.

Nonetheless, she had a theory:

"It currently has a huge number of hosts (people) to infect and so has no pressure to mutate. But as more people develop immunity it will have to work a lot harder and so we will expect to see drift (mutations) which might be accompanied by changes in its virulence."

That might of course mean that swine flu has a sting in its tail. "Pandemic, what pandemic?" has been the refrain from some journalistic colleagues recently. And it's true that the first pandemic of the 21st Century is a viral pushover for the vast majority of us.

But for a small minority it is a serious threat, hospitalising hundreds of Britons each week, a good proportion of whom have no underlying health problems.

The sooner we know why flu is able to breech the defences of some people and not others, the sooner we might be able to develop better ways to beat the virus.


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