Officials Facing Shortage of Rabies Vaccine

Submitted by SadInAmerica on Sat, 09/13/2008 - 12:50am.

Public health authorities on both sides of the Canada-U.S. border are trying to reduce demand for rabies vaccine in the face of a serious supply problem expected to persist well into next year.

Supply limitations have officials scrambling to try to avoid what would be a public health nightmare -- a shortage of a vaccine that literally means the difference between life and death for people truly exposed to the rabies virus.

"The rabies vaccine supply is tight," said Dr. John Spika, a senior official with the Public Health Agency of Canada. "We are concerned."

The Public Health Agency has been exploring the possibility of sourcing vaccine from manufacturers not licensed to sell in Canada, said Spika, acting director general for the centre for immunization and respiratory infectious diseases. Unlicensed vaccine would have to be imported under a "special access" program for drugs and biological products.

In the United States, authorities have formed a working group to explore what options would be available should demand outstrip supply.

Proposals include using an alternative dose and ramping up control measures aimed at reducing rabies in wild animals, said Charles Rupprecht, chief of the rabies program at the Centers for Disease Control in Atlanta, Ga.

"We've been playing these scenarios as to what we would do," admitted Rupprecht, who said the CDC, the Food and Drug Administration, the U.S. Department of Health and Human Services, vaccine makers and other involved parties are in "very frequent" contact as they try to manage access to the scarce supplies.

The situation is the product of an unfortunate confluence of factors.

Sanofi Pasteur, one of two manufacturers licensed to supply vaccine to Canada and the U.S., is upgrading its manufacturing facility in France. It stockpiled vaccine to meet expected need, but while the plant has been down demand has soared due to outbreaks in wild animals.

When will the supply problem ease? "By this time next year. We hope. They hope. Everybody hopes," Rupprecht said.

Steps have already been taken in both countries to reduce non-emergency use of the vaccine.

Vaccination programs have been suspended for people who work in high-risk professions - animal control officers, veterinarians and people who work in labs that test for rabies.

In normal times, people in these jobs would be offered pre-exposure vaccination because their risk of having contact with a rabid animal or the rabies virus is real.

And travellers going to high-risk settings don't currently have the option of arranging to be vaccinated before setting off.

For now, available supplies are being reserved for what's known as post-exposure prophylaxis -- a term that means preventative treatment after exposure. It involves a series of five shots of vaccine. In Canada, roughly 34,000 doses (individual shots) of rabies vaccine are used annually.

Post-exposure treatment is ordered for anyone who had contact with the saliva of an animal that tested positive for rabies. It may also be suggested for people who have had close contact with a potentially rabid animal that could not be held for observation or euthanized for testing - for instance, a strange dog that bit and fled or a bat that flew out of an open window.

Spika recalled the impulse from when he was a practising physician. "The knee-jerk response was: Why not give it? What's the harm?... Particularly if the patient was upset."

Studies suggest too much of this post-exposure vaccinating is going on. Because untreated rabies is virtually always fatal, doctors and local public health officials have traditionally set the bar very low when deciding whether vaccination is in order.

"We've known for a long, long time -- from the data, from the evidence -- that the vast majority of prophylaxes that go on are probably not needed nor in some cases appropriate," Rupprecht said.

"We've got a continuum from when it's always appropriate to situations - for example if it was a bird - that it's never appropriate. Let alone an insect."

"Believe me - we get these calls," he said.

Before the new millennium, a U.S. health promotion campaign called Healthy People 2000 had as one of its goals reducing unnecessary rabies vaccine administration. The target was to cut the annual number in half.

"And we saw an interesting phenomenon," Rupprecht said.

"Not only was it not cut in half, down to what we had hoped for at the time - between 9,000 and 10,000 cases - but it actually doubled. To the extent that now we're seeing, in the 21st century, somewhere between 20,000 and 40,000 human exposures per year."

When supply is plentiful, that overuse is perhaps not a major concern. But while supply is so tight, experts believe this "when in doubt, vaccinate" approach could trigger a vaccine shortage.

Recently the CDC put out an advisory to doctors as well as state and local public health officials strongly recommending "judicious and appropriate use of rabies vaccines . . . to avert a situation in which persons exposed to rabies are put at increased risk due to depleted vaccine supplies."

And Novartis, the other vaccine manufacturer, said it will require American doctors who want to give rabies shots to their patients to first get a confirmation code from public health authorities. That step is meant to ensure that an adequate risk assessment is conducted before treatment is given.

But is the message sinking in? Rupprecht isn't sure.

"It's like anything else. You don't really pay attention until it's the moment at hand."

September 11, 2008 - source CanadaTV

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Submitted by SadInAmerica on Sat, 09/13/2008 - 12:50am.