How Effective Is The New Flu Vaccine? Some people say they won't get a flu vaccine — against seasonal flu or H1N1 — because they believe it doesn't work. It's true that the seasonal flu vaccine doesn't stop all cases of the flu in people who get it. But just how effective is the new H1N1 vaccine?
NPR logo

How Effective Is The New Flu Vaccine?

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript
How Effective Is The New Flu Vaccine?

How Effective Is The New Flu Vaccine?

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript


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.

Copyright © 2009 NPR. All rights reserved. Visit our website terms of use and permissions pages at for further information.

NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.