Published online 9 July 2008 | Nature | doi:10.1038/news.2008.945

News: Briefing

Whatever happened to bird flu?

The media frenzy over bird flu has receded, but the threat of a global epidemic still looms large.

BirdsBird flu: it's still out there.TBKMEDIA.DE/ALAMY

Is bird flu affecting fewer people now?

Yes and no. The 88 cases and 59 deaths reported last year are lower than the 2006 peak of 115 cases and 79 deaths, when the virus first arrived in Turkey and Egypt and sparked a large number of cases there. Thirty four cases have been reported so far this year.

Vietnam, Thailand and China — the only countries to report cases from 2003–04 during the current epidemic — have made progress in controlling the spread of the virus in poultry. Once major hotspots, all three countries have consequently seen a significant drop in human cases.

But cases have since cropped up in 12 other countries, with Indonesia leading at 135 cases — more than one-third of the worldwide total of 385. A major worry is that Bangladesh, which reported its first human case in May, might go the way of Indonesia because the virus is firmly established in the country's poultry. The apparent current downturn in cases could be short-lived.

What is the situation in poultry?

Although some countries are making progress controlling the disease, the prospects are bleak. Experts are now convinced that the disease has become endemic in Indonesia, Bangladesh, Vietnam and Egypt, making eradication impossible. That makes it inevitable that outbreaks will continue elsewhere as the poultry trade helps to spread the virus.

In 2007, outbreaks in poultry or wildlife were reported in 28 countries. Twenty two countries have reported outbreaks this year, with South Korea having its worst outbreak ever in April. Sixty one countries have now been affected, and the H5N1 virus remains a major threat to agriculture and food supply, and to human health.

Short-term fire-fighting tactics are now evolving into long-term efforts, including restructuring trade and farming practices. "Acceptance that the viruses will not be eradicated does not mean complacency — it is a dose of reality. But it also takes the disease out of the headlines," says Les Sims, a consultant for the United Nations Food and Agriculture Organization. "If governments are to tackle these issues, long-term donor support is needed. Unfortunately, long-term programmes may prove less appealing to donors than emergency activities, especially if the disease is no longer front-page news."

One problem is that most countries don't have systems for rapidly incorporating new antigens into vaccines, making current poultry vaccines in high-risk areas increasingly ineffective.

Might bird flu still reach the Americas?

Yes. That it hasn't already is mostly down to good luck, and relative geographic isolation. If it enters the Americas it could be a disaster for the food industry in Latin America — Brazil is the largest producer of poultry.

If the risks are still there, why has the media largely gone quiet? Media coverage of avian flu peaked from mid-2005 to mid-2006. That was when H5N1 avian flu erupted out of Asia, spread across Russia, and fanned out into Europe and Africa. Although bird flu has since faded from the front pages, media coverage in fact remains sustained and high, as can be seen from a timeline search of the Google News archive.

What's being done to prepare for a pandemic?

Many countries — Canada in particular — have made considerable progress in planning to mitigate a pandemic, compared with just three years ago when only a few had national pandemic plans. But implementation remains patchy.

What progress has been made in vaccines?

Plenty. Vaccines with adjuvants that boost their effectiveness by making antigens go much further — a crucial factor in a pandemic — are belatedly getting the attention they deserve, despite the inertia of regulators, governments, and research agencies. Current formulations are so antigen-sparing that todays flu-vaccine production capacity would be enough to vaccinate everyone on Earth.

But vaccines can't be made until a pandemic starts, and the particular pandemic strain has been identified. So it will be a race against the clock, requiring an unprecedented level of international coordination. As things stand, vaccines wouldn't be available until several months into a pandemic, and the nine countries that have the flu-vaccine factories are likely to keep the first batches for themselves. Taiwan, Korea, Brazil and Mexico are now developing their own flu-vaccine facilities.

What are the alternatives to a perfectly matched vaccine?

A Commentary in this week's issue of Nature highlights the possibility of using pre-pandemic vaccines matched to earlier strains of H5N1. Even if these were only partly effective, they might confer sufficient protection to prevent death or severe disease.

The World Health Organization is planning to stockpile more than 100 million doses of pre-pandemic vaccines, and some nations, including Japan, are considering the same.

But the cruel reality is that without greater international effort, vaccines and antivirals are not going to be available to most of the world's population who live in poor countries. David Fedson, former director of medical affairs at the drug firm Sanofi-Aventis, argues that cheap, generic anti-inflammatory drugs that are widely available in poor countries could help to reduce death and severe disease during a pandemic. They could calm the massive overreaction of the immune system, called a cytokine storm, that is the main killer in flu. 

Read more about the long war on avian flu in a Nature Editorial this week.

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