Avian Flu - What we need to know

US to stockpile Relenza

The U.S. health department said it ordered about 1.75 million courses of Relenza on March 2 and another 2.2 million courses on March 26.

The department has already ordered 22 million courses of Tamiflu, which until the launch of Relenza was the only drug on the market with the capabilities to prevent influenza A and B and also be used as a treatment for people with the infection.

From CNN.

WHO to send 70,000 Tamiflu doses to Iraq

The World Health Organisation announced that tens of thousands of doses of Tamiflu were set to arrive in Iraq to help fight bird flu in the country's Kurdistan region.

Fadela Chaib, spokeswoman for the UN health agency, said the shipment was scheduled to arrive in Baghdad later Friday and would then be sent north to the affected area.

Source. Of course, the Tamiflu would still need to be distributed in a timely (24-48 hours after catching the virus) and orderly manner in an outbreak. This is quite the challenge in any country, and could be extremely difficult in Iraq. In the end there is no substitute for good local infrastructure and planning. For a quick read on some of the difficulties for preparing for bird flu in Iraq read this Reuters article.

Roche claims Tamiflu could still be effective

Roche said on Friday tests on animals showed Tamiflu could work against the current virus but that more studies were needed into how much Tamiflu should be given in order to effectively combat the virus in humans.

"The results suggest that Tamiflu can prevent H5N1 mortality in animals," Roche said in a statement on Friday.

"However, further studies are needed to identify the optimal dose of Tamiflu administered later (24 and 48 hours) after the infection with the virulent H5N1 virus," the firm said.

Source. The press release was in response to an article published yesterday in the Lancet medical journal. Here is another critical take on the Lancet piece.

Tamiflu ineffective in a pandemic?

There is no evidence that Tamiflu, the drug being stockpiled by Britain, the United States and Europe, will work if a flu pandemic takes off in humans, according to a review published today by the Lancet medical journal.

None of the four existing drugs against influenza has much effect, the paper says. The authors strongly warn against relying on drugs to stamp out a potential avian flu pandemic, saying complacency could get in the way of more useful public health measures - such as hygiene and isolation - to stop the spread of infection.

[...] While the drugs might reduce patients' symptoms, the authors say the use of Tamiflu could actually increase the spread of the flu virus. If people take the drug and have fewer symptoms they may end up going to work and spreading the potentially lethal virus.

From the Guardian. Last week the CDC reported the common influenza has grown increasingly resistant to antivirals, adding to the concern the drugs may not be effective in a flu pandemic.

CDC: common flu resistant to antivirals

The government, for the first time, is urging doctors not to prescribe two antiviral drugs commonly used to fight influenza after discovering that the predominant strain of the virus has built up high levels of resistance to them at alarming speed.

A whopping 91 percent of virus samples tested by the Centers for Disease Control and Prevention this flu season proved resistant to rimantadine and amantadine, a huge increase since last year, when only 11 percent were.

The discovery adds to worries about how to fight bird flu should it start spreading among people. Health officials had hoped to conserve use of two newer antiviral drugs, Tamiflu and Relenza, because they show activity against bird flu, unlike the older drugs.

Source.

Tamiflu use in Turkey

Turkish officials have been stressing that relatively few people there have died, compared to Asia, where H5N1 has had about a 50-percent mortality rate. WHO said there is no evidence the virus has changed greatly and says patients have been infected by close contact with sick poultry -- in most cases children playing with birds or helping families kill them. "Compared to the numbers in Asia, we do not have too many deaths at the moment," said Dr. Guenael Rodier, head of the WHO mission to Turkey, told a news conference. "We need to investigate this and to see if the use of Tamiflu has played a role in the (smaller) numbers," he said. "I have the feeling that what is going on in Turkey can be brought under control relatively easily like in Asia," Rodier added. "At the moment, there is good awareness. We will try to keep some kind of momentum on these issues for months to come."

From ProMedMail.

More reactions to study on Tamiflu resistance

Earlier this week the New England Journal of Medicine published an article revealing a number of Vietnamese patience infected with H5N1 had developed resistance to Tamiflu during their treatment. Here are some of the latest reactions to the article.

Effect Measure sensibly points out Tamiflu was never going to be a “magic bullet” in the first place:

Tamiflu was never going to get us that far in mitigating the effects of a pandemic anyway because our ability to supply, dispense and provide the collateral medical support was never there. Nor could it be effectively used on a mass population basis.

(Tyler also argued we should not put all our faith in a centralized stockpile of Tamiflu, read his policy paper here.)

At the other end of the spectrum, two articles from Reuters and the Guardian seem to be trying to minimize the importance of the NEJM study and argue Tamiflu is still quite effective:

Keiji Fukuda, a scientist at the WHO's global influenza programme, said some resistance was inevitable with any kind of drug.

"Whenever you use any kind of drugs, antivirals or antibiotics, you expect to see resistance develop in organs. Finding some resistance in and of itself is not surprising and is not necessarily alarming," he told Reuters.

and

"Whilst there is some anecdotal evidence of the build-up of resistance to antiviral drugs such as Tamiflu, at present the experience is that these drugs do work and that they should work against a pandemic strain," a Department of Health spokeswoman said.

Resistance to Tamiflu

Influenza A (H5N1) virus with an amino acid substitution in neuraminidase conferring high-level resistance to oseltamivir was isolated from two of eight Vietnamese patients during oseltamivir treatment. Both patients died of influenza A (H5N1) virus infection, despite early initiation of treatment in one patient. Surviving patients had rapid declines in the viral load to undetectable levels during treatment. These observations suggest that resistance can emerge during the currently recommended regimen of oseltamivir therapy and may be associated with clinical deterioration and that the strategy for the treatment of influenza A (H5N1) virus infection should include additional antiviral agents.

That is the abstract of an article from the latest edition of the New England Journal of Medicine. Not surprisingly, Roche stock was down on the news.

Addendum: Today's Guardian presents the UK government's reaction to the study. Here's an excerpt:

"Whilst there is some anecdotal evidence of the build-up of resistance to antiviral drugs such as Tamiflu, at present the experience is that these drugs do work and that they should work against a pandemic strain," a Department of Health spokeswoman said.

Effect Measure on Tamiflu

Revere has a good post explaining why Tamiflu is not a magic cure.

The latest from China

[A] team of WHO experts traveled to China's central region where a bird flu outbreak was reported among poultry. Three people fell ill in the same village in Hunan, including a 12-year-old girl who died, after the government reported 545 chickens and ducks died of bird flu last month. The H5N1 bird flu virus has not been ruled out as the cause of the human infection.

The six-member WHO team is expected to stay a week, working with Chinese officials to investigate the outbreak, said Roy Wadia, WHO spokesman in Beijing.

China also reported a new bird flu outbreak in poultry in Huainan, a city in the eastern province of Anhui its ninth outbreak since Oct. 19, China Central Television said.

Another report said China had developed its own version of Tamiflu, an antiviral drug believed to be the best treatment available for bird flu in humans.

Zhong Nanshan, director of the Guangzhou Institute of Respiratory Diseases, said the Chinese drug has some effect against the virus, according to an interview published Sunday in the Information Times newspaper. It did not give any details about the drug or when it might be available.

Source.

China also announced it will close the Xianghai National Nature Reserve to prevent tourists from getting infected with bird flu.

Today there were reports of a suspected human case in Liaoning:

"They said that there is a female poultry worker who's been diagnosed with pneumonia and she's regarded as a possible human case (of bird flu) -- they've not excluded her," said Roy Wadia, the WHO's China spokesman.