All Things Considered

How Effective Is The New Flu Vaccine?

By Joanne Silberner

Published November 9, 2009 4:00 PM

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The swine flu vaccine may have become synonymous with long lines — and short supply. So is it worth the wait and frustration to get vaccinated?

The vaccine is 70 to 90 percent effective, and that's good enough for Anthony Fauci, who heads the National Institute of Allergy and Infectious Diseases. He says no vaccine is ever 100 percent effective, but the efficacy rate of the swine flu vaccine is "enough to have a major impact on disease and on the spread of this virus."

The estimate comes from measurements of antibodies that appear in the bloodstreams of people who've been vaccinated. Those antibodies indicate that the immune systems of those vaccinated are primed and ready to fight the virus.

In people over 65, early studies suggest the new H1N1 vaccine is only 50 percent effective. That's about what it is with the seasonal flu vaccine. Older people in general have weaker immune systems. But even at 50 percent, health researchers say it's worth it.

"When the vaccine supply becomes greater, assuming we're still experiencing problems with the infection, getting the vaccine would reduce the risk of getting the infection" says Lisa Jackson of Group Health Research Institute in Seattle.

Federal authorities have been careful all along to say that people should weigh the risks and benefits themselves. That's a difficult calculation for a lay person, but one short cut is to ask officials if they're getting vaccine.

For instance, President and Mrs. Obama are not getting the vaccine, because they're not in a priority group. But their daughters do fall into a CDC priority group — people between 6 months and 24 years old.

The new vaccine isn't expensive. The government is paying less than $10 a dose, and providing it free to clinics and doctors. So far, the vaccine appears to be as safe as the seasonal flu vaccine, except for people with egg allergies.

That said, there are still some big unknowns with the new H1N1 vaccine. While millions of doses have now been given without any problems being seen, safety problems could arise. That's unlikely, but possible.

It's more likely that the virus itself will mutate. Regular seasonal flu viruses mutate regularly, that's why there's a new seasonal flu vaccine every year.

View Transcript

MELISSA BLOCK, host:

The swine flu vaccine may have become synonymous with long lines and short supply. So, is it worth the wait and the frustration to get vaccinated?

NPR's Joanne Silberner examines the question of how effective the vaccine is.

JOANNE SILBERNER: Fifty-five-year-old Christine Chase(ph) of Davis, California is recovering from swine flu now. She wishes she had gotten the vaccine before getting sick. Her symptoms began with a crashing headache.

Ms. CHRISTINE CHASE: It started off that way, then a cough, and then you got really, you know, just feel like the stuffing came out of you, you know, get hit by a truck feeling, and then incredibly high fever.

SILBERNER: Being sick with an H1N1 swine flu infection has made her a positive zealot about the new vaccine.

Ms. CHASE: This has shaken me up, and I'm going to look at the flu a little bit differently now. I'm sure now.

SILBERNER: She tells everyone she can to try and get the vaccine.

But had Chase been able to get the vaccine before she got sick, would it have saved her from the headache and the fever and the terrible cough? Most probably, yes.

Tony Fauci heads the National Institute of Allergy and Infectious Diseases, which has run a series of studies on the vaccine's effectiveness. He says blood tests on vaccinated people show they're ready to fight off infection at least as well, if not better, than with seasonal flu vaccines.

Dr. ANTHONY FAUCI (Director, National Institute of Allergy and Infectious Diseases): You can protect against confirmed influenza in about 70 to 90 percent of healthy adults who are less than 65 years old, as is always the case.

SILBERNER: That's really good, he says.

Dr. FAUCI: It is never 100 percent. It will never be 100 percent, but it's enough to have a major impact on disease and on the spread of this virus.

SILBERNER: But the 70 to 90 percent number, that's for people under 65. For people over 65, it's different. As we age, our immune systems tend to get weaker, so the vaccine that's supposed to stimulate the immune system to create antibodies to fight off infection cannot do as well.

Lisa Jackson is with Group Health Research Institute in Seattle, and she has been studying the effectiveness of this new flu vaccine in older people.

Dr. LISA JACKSON (Researcher, Group Health Research Institute): Fifty percent of the people, in this early look at our studies, seem to have enough antibodies that we would think that they would be protected against infection.

SILBERNER: That 50 percent protection is about what you'd expect from regular seasonal flu vaccines. Right now, seniors aren't on the priority list for the new vaccine because they're not getting infected as often. Still, some older people are getting the flu, and when they do, they can get very sick. So, Jackson says the vaccine isn't a bad idea.

Dr. JACKSON: Once there's a sufficient vaccine supply - seniors are at some risk of infection and getting the vaccine can only reduce that risk - it is probably warranted for the seniors who would like to reduce their risk of getting H1N1 infection.

SILBERNER: And even if it's only 50 percent protection, that's better than nothing with this new flu, says Christine Chase, who's been struggling to recover. Chase says she would've gotten the vaccine even if doctors could have only offered her a 20 or 30 percent chance it would work. There is, of course, a caveat to the effectiveness studies: The new flu virus could mutate. Flu viruses do that, that's why there's a new seasonal flu vaccine every year.

So far, no signs of that yet, but scientists are watching for it. If the virus mutates into a form the vaccine doesn't fight so well, a new vaccine will be needed. Joanne Silberner, NPR News. Transcript provided by NPR, Copyright National Public Radio.

Source: NPR

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