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Archive for Monday, September 28, 2009

Tracking vaccine’s possible side effects

September 28, 2009

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Swine Flu Pandemic

An outbreak of H1N1 Swine Flu was reported in Mexico in April 2009. By the end of May, it had spread across the U.S., with all 50 states reporting cases.

Kathleen Sebelius, secretary of Health and Human Services, from left, talks with Mayo Clinic Vaccine Research Group Director Dr. Gregory A. Poland and American Academy of Pediatrics President Dr. David T. Tayloe at the National Press Club in Washington in this Sept. 10 file photo. An unprecedented system to track possible side effects from swine flu vaccinations will begin next month.

Kathleen Sebelius, secretary of Health and Human Services, from left, talks with Mayo Clinic Vaccine Research Group Director Dr. Gregory A. Poland and American Academy of Pediatrics President Dr. David T. Tayloe at the National Press Club in Washington in this Sept. 10 file photo. An unprecedented system to track possible side effects from swine flu vaccinations will begin next month.

— More than 3,000 people a day have a heart attack. If you’re one of them the day after your swine flu shot, will you worry the vaccine was to blame and not the more likely culprit, all those burgers and fries?

The government is starting an unprecedented system to track possible side effects as mass flu vaccinations begin next month. The idea is to detect any rare but real problems quickly, and explain the inevitable coincidences that are sure to cause some false alarms.

“Every day, bad things happen to people. When you vaccinate a lot of people in a short period of time, some of those things are going to happen to some people by chance alone,” said Dr. Daniel Salmon, a vaccine safety specialist at the Department of Health and Human Services.

Health authorities hope to vaccinate well over half the population in just a few months against swine flu, which doctors call the 2009 H1N1 strain. That would be a feat. No more than 100 million Americans usually get vaccinated against regular winter flu, and never in such a short period.

How many will race for the vaccine depends partly on confidence in its safety. The last mass inoculations against a different swine flu, in 1976, were marred by reports of a rare paralyzing condition, Guillain-Barre syndrome.

“The recurring question is, ‘How do we know it’s safe?’” said Dr. Gregory Poland of the Mayo Clinic.

Enter the intense new monitoring. On top of routine vaccine tracking, there are these government-sponsored projects:

• Harvard Medical School scientists are linking large insurance databases that cover up to 50 million people with vaccination registries around the country for real-time checks of whether people see a doctor in the weeks after a flu shot and why. The huge numbers make it possible to quickly compare rates of complaints among the vaccinated and unvaccinated, said the project leader, Dr. Richard Platt, Harvard’s population medicine chief.

• Johns Hopkins University will direct e-mails to at least 100,000 vaccine recipients to track how they’re feeling, including the smaller complaints that wouldn’t prompt a doctor visit. If anything seems connected, researchers can call to follow up with detailed questions.

• The Centers for Disease Control and Prevention is preparing take-home cards that tell vaccine recipients how to report any suspected side effects to the nation’s Vaccine Adverse Event Reporting system.

“We don’t have any reason to expect any unusual problems with this vaccine,” said Dr. Neal Halsey, director of Hopkins’ Institute for Vaccine Safety, who is directing the e-mail surveillance.

After all, the new H1N1 vaccine is a mere recipe change from the regular winter flu shot that’s been used for decades in hundreds of millions of people without serious problems. Nor have there been any red flags in the few thousand people given test doses in studies to determine the right H1N1 dose. They’ve gotten the same sore arms and occasional headache or fever that’s par for a winter flu shot.

But because this H1N1 flu targets the young more than the old, this may be the year that unprecedented numbers of children and pregnant women are vaccinated.

Then there’s the glare of the Internet — where someone merely declaring on Facebook that he’s sure the shot did harm could cause a wave of similar reports. Health authorities will have to tell quickly whether there really do seem to be more cases of a particular health problem than usual.

So the CDC is racing to compile a list of what’s normal: 25,000 heart attacks every week; 14,000 to 19,000 miscarriages every week; 300 severe allergic reactions called anaphylaxis every week.

Any spike would mean fast checking to see whether the vaccine really seems to increase risk and by how much, so health officials could issue appropriate warnings.

Very rare side effects by definition could come to light only after large-scale inoculations begin — making this the year scientists may finally learn whether flu vaccine truly is linked to Guillain-Barre, an often reversible but sometimes fatal paralysis.

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