BioEd Online

The dearth of flu vaccine in the United States is having one small, unforeseen benefit: people are flocking to join clinical trials of new ways to defeat the disease and, perhaps, fuelling advances in protection.

Since a manufacturing hitch unexpectedly halved the country's vaccine supply earlier this month, remaining stocks are being reserved for infants, the elderly and others at high risk. But even individuals in these groups are struggling to find supplies and reports abound of long lines outside clinics.

Despite the shortage, some research groups are still able to run clinical trials that aim to figure out how best to use the existing vaccine. And some are testing experimental drugs or vaccines for the future. For healthy adults, "it's the only way such a person could be vaccinated," says flu researcher John Treanor at the University of Rochester, New York.

New recruits

One trial, headed by virologist Pedro Piedra at Baylor College of Medicine in Houston, Texas, is testing whether the spread of the influenza virus can be curbed by blanket vaccination of all school-age children in a local area. Children are the most likely to get infected and to pass on the disease to others, so the researchers hope to discover whether it makes sense to target this group with vaccines in the future.

Because the trial is pretty much the only way many families can find a jab for their kids, Piedra says the group has immunized around 3,000 children in ten days, a process that would normally take over six weeks. "We've had a record pace in the last few weeks," he says.

The interest in clinical trials is also helping those testing experimental vaccines, such as those that are grown in cells cultured in the laboratory rather than in hen eggs. Researchers are particularly keen on testing and refining these vaccines, because they can be produced quickly, avoiding the hold-up of having to order eggs many months in advance.

Treanor is recruiting around 400 healthy adults below the age of 49 who are willing to receive a syringe-full of a vaccine grown in insect cells, which was tested in the elderly last year. With the current shortage, "it's certainly going to be easier to recruit subjects," he predicts.

At least one company is willing to take any number of healthy people into their trial. GenoMed, based in St Louis, Missouri, wants to test whether drugs that are commonly used to treat high blood pressure, called ACE inhibitors, can also fight flu. The company already has preliminary evidence that the therapy wards off West Nile virus, and the opportunity to test it on flu during the current shot shortage "was too good to pass up," says GenoMed chairman, David Moskowitz.

Trial by e-mail

ACE inhibitors bind receptors on the cells of disease-fighting white blood cells, which swamp the body during a flu infection. They trigger the cells to commit suicide, which damps an overactive immune response and can actually ease symptoms, Moskowitz believes.

Anyone interested can enrol by printing a form from the company's website and taking it to their doctor in order to get a prescription for the drugs; the company then sends follow-up e-mails to check on subjects' progress. About 100 people have shown an interest so far. Although the approach is experimental, Moskowitz says the drugs are widely used and safe enough to pose little risk.

Scientists in the field say they are unsure whether the surge of interest in these new techniques, from both the public and policy-makers, will last if next season's vaccine supply arrives without a hitch. But for now, Treanor says, "I can't imagine it'll do anything but stimulate research."