THERE are certain warnings signs that really should be acted upon. This week鈥檚 announcement by health officials in Thailand of the first probable human-to-human spread of the H5N1 bird flu is one of those signs. The virus may not be spreading easily among humans yet 鈥� on this occasion it passed only after sustained contact between a girl and her distraught mother 鈥� but to ignore it would be reckless.
When a virus adapts to a new host, it faces two challenges. It must deflect the host鈥檚 immune response enough to replicate. Then the hordes of newly made virus particles must find a way out so they can infect others. H5N1 has learned to grow in people. It may now be finding the escape route. This is worrying, not least because the virus has so far killed three out of every four people it has infected.
What we need is a vaccine, and fast. Luckily we have a candidate, though it is so new we do not know how well it works. Even so, the US government is worried enough about bird flu in Asia that it announced plans this week to make 2 million doses of the vaccine (see 鈥淏ird flu goes human-to-human鈥�). This is good news. Industry will learn the ropes, and some people will be protected if this particular H5N1 ever does cut loose. But even if the vaccine works, 2 million flu shots will not do much in a world of 6 billion people. This is particularly true if, as seems likely, the vaccine is deployed in the US, while the H5N1 flu, if it goes pandemic, will probably spread from Asia.
Advertisement
What we need is a global capacity to make large amounts of flu vaccine fast. Say, a dozen state-of-the art plants scattered about the planet, growing vaccine virus in cultured cells, ready to be scaled up when needed. These plants could operate under a global authority with the resources to get vaccine to where epidemiologists say it is needed, ideally to squash any outbreak before it becomes a pandemic.
Sooner or later, H5N1 or one of its cousins will find a way to spread easily between humans. If most of us are vaccinated, it will not get far. It is time for some urgent lateral thinking.