Will This Year's Flu Shot Work?

Will This Year's Flu Shot Work?

Will This Year's Flu Shot Work?

Vaccinated People Who Do Get Flu Likely Won't Be as Sick

Dec. 3, 2003 -- Fujian flu is here. Will flu vaccine protect you?

That depends on what you mean by "protect." The CDC says flu vaccine will offer "some" immunity against the Fujian flu that's going around this year. Some people are expected to get the flu even though they got vaccinated. But they won't get as sick as those who didn't get the vaccine.

Fujian flu is what scientists call a "drift variant." It's nearly the same virus as the Panama flu included in this year's vaccine. But it's not exactly the same, notes Jennifer Wright, DVM, an officer in the epidemic intelligence service at the flu branch of the CDC.

"We just don't really know how well the vaccine will protect against the Fujian variant," Wright tells WebMD. "In the past, where a drift variant didn't match the vaccine strain exactly, some vaccinated people didn't get sick, and those who did, had a milder illness. We'll be looking to see if that's true this year."

It would be great if scientists could look at a virus and guess how bad it would be. That's just what the CDC is doing. And "guess" is a big part of it.

"We're doing tests on Fujian viruses coming from infected people," Wright says. "Those tests are showing protection in laboratory studies. But we don't know how that translates into a living human body."

Drift and Shift

The Fujian flu is one kind of new flu virus. If you've got to have a new flu, this kind -- a drift variant -- is probably the best kind. Drift variants arise when a lot of people become immune to a circulating flu virus. They're just different enough to be able to spread more than their parent strain.

But a drift variant is nothing compared to a shift variant. Shift variants are flu bugs that have managed to change one or both of their two kinds of surface molecules. This lets them entirely escape any immunity because of prior vaccination or infection, says Harry L. Keyserling, MD, director of pediatric infectious diseases at Emory University in Atlanta.