Drug Firms Cautious on Vaccine for West Nile

As public concern about West Nile virus has intensified, so has the push to create a vaccine.

Several drug companies are considering developing new medical protections against the virus, including Emeryville, Calif.-based Chiron Corp.

But even though West Nile might look like a solid business opportunity as it spreads to new parts of the country, drug makers are mindful of what happened with Lyme disease, which didn’t produce the windfall that had been expected. Although Lyme disease, spread by a tick bite, remains prevalent in wooded areas of the Northeast and upper Midwest, the only vaccine against the illness was discontinued in 2002 because of low demand.

So drug companies are approaching West Nile virus with caution.

Chiron, in the early stages of research, is waiting to see how far the disease spreads before committing to a full-scale effort.

“We have one eye in the lab and the other on the virus,” Chiron spokesman John Gallagher said.

The stakes for the companies are big. The market for a vaccine could exceed $300 million, according to some estimates.

Beyond the economics of it, there is a sense of urgency from a public health standpoint.

Although most people with West Nile virus don’t get sick, the disease can be deadly. The virus has killed more than 400 people nationwide since 1999, including an Orange County man in June and a San Bernardino man in July. A 91-year-old Northridge woman who died last week was tentatively diagnosed with the disease, a spokeswoman at Kaiser Permanente Panorama City Medical Center said Sunday.

Elderly people and those with weakened immune systems are most susceptible. One in 5 people who contract it develops symptoms, such as fever and muscle aches. About 1 in 150 infected people suffers the worst form of the disease, an inflammation of the brain. There is no treatment for the virus.

Public health officials believe that West Nile virus, first spotted in the U.S. in 1999 and detected in California last year, will become a lasting menace. What experts can’t yet predict is how big a problem the disease will become. The virus is spread by mosquitoes, so weather conditions play a key role. Local mosquito eradication efforts can alter the course of the disease.

A veterinary vaccine against West Nile virus is available for horses, but big vaccine companies have been slow to pursue a human version, a more costly undertaking. To spur industry on, the National Institutes of Health offered multimillion-dollar grants for vaccine development. Now, two small biotech companies are racing to be first with a product.

One, British company Acambis, has just started testing its vaccine in people. Its rival, Aiea-based Hawaii Biotech, in June announced that all 60 hamsters that received its vaccine were protected from disease.

“Our thinking is the disease is likely here to stay and spread,” Acambis Chief Executive Gordon Cameron said.

The companies say media reports about people wearing long sleeves or staying indoors to avoid bites from infected mosquitoes -- what Cameron dubbed the barbecue effect -- indicate that demand is strong.

“You are outside and a mosquito lands on your arm and you wonder if there is virus in the blood of that mosquito,” Cameron said. “There is an element of fear at work here.”

There’s no question that fear is a powerful driver of vaccine sales. An early and hard flu season last winter boosted demand for shots and resulted in shortages. Chiron and rival Aventis Pasteur Inc., the only suppliers of flu shots to the U.S., have already sold their entire production of 100 million doses for this year’s season, a record amount.

But during the mild flu season of 2001, Swiftwater, Pa.-based Aventis threw out millions of doses of unsold flu vaccine.

In the case of Lyme disease, fears that drove many in the Northeast to avoid wooded areas dissipated by the time British-based GlaxoSmithKline launched its vaccine in 1999, said Grant L. Campbell, chief of the unit charged with tracking West Nile virus at the Centers for Disease Control and Prevention.

Lyme disease causes flu-like symptoms, including fever and chills, and arthritis that may linger for years, but it is rarely fatal. According to a CDC study, it was cheaper to treat Lyme disease patients with antibiotics than to prevent illness with a vaccine. By 2002, Glaxo faced not only weak demand for its vaccine but the added problem of lawsuits from people who said the shot had made them ill.

It isn’t enough “that a vaccine is reasonably effective,” Campbell said. “It has to be used and needed and worth the added expense for everybody.”

Of course, there’s no assurance that an effective vaccine will emerge from the development programs now underway. Acambis, which is publicly traded, had a setback when two people who received its experimental vaccine had protein in their urine, a sign of possible kidney damage. Cameron doesn’t believe the vaccine was the cause, but the company is conducting additional tests to be sure.

Privately held Hawaii Biotech faces a potential drawback in that its vaccine would require a booster shot. The Acambis vaccine is administered in one dose.

Also uncertain is the course of West Nile virus. An early spring prolongs the mating season for birds, which harbor the virus. A wet spring followed by a dry summer, Campbell said, favors mosquitoes, which acquire the virus when they bite infected birds.

Conditions change locally from season to season, making the virus a gamble for vaccine makers. “It could be feast or famine, with big years and small years, with geographic unpredictability and no steady state,” Campbell said.

David Watumull, chief executive at Hawaii Biotech, said: “It comes down to trying to analyze fear.” But at this point, he added, “we’re convinced there is a significant opportunity.”