Question: How do scientists know how to make a flu vaccine if viruses can be different every year?

Asked by sarahb to Soon, Kym, Natasha, Steven, Vanessa on 31 Aug 2012.

0

Keywords: ,

  1. Photo: Steven HamblinSteven Hamblin
    answered on 31 Aug 2012:

    Great question! The flu vaccine actually represents the ‘best guess’ that the research community has about what flu strains will be the most common in the upcoming year. The vaccine will protect against against 2-3 strains specifically, and will often give at least partial protection against other strains depending on how well the strains we actually ‘match’ the ones we vaccinate against. Sometimes the best guess is better, sometimes it’s a little worse, but scientists who work on the flu do a lot of work every year to make the vaccine as good as it can be, and we’re getting better at it all the time!

    The Centres for Disease Control in the United States has a good page about this if you want to read more. I’m going to quote one section here for you to read:

    Can I get seasonal flu even though I got a flu vaccine this year?

    Yes. The ability of flu vaccine to protect a person depends on two things: 1) the age and health status of the person getting vaccinated, and 2) the similarity or “match” between the virus strains in the vaccine and those circulating in the community. If the viruses in the vaccine and the influenza viruses circulating in the community are closely matched, vaccine effectiveness is higher. If they are not closely matched, vaccine effectiveness can be reduced. However, it’s important to remember that even when the viruses are not closely matched, the vaccine can still protect many people and prevent flu-related complications. Such protection is possible because antibodies made in response to the vaccine can provide some protection (called cross-protection) against different, but related strains of influenza viruses.

    0

  2. Photo: Natasha LangleyNatasha Langley
    answered on 3 Sep 2012:

    Excellent question! I’ve actually never thought of that myself….

    So, it turns out that the viruses they want to make the annual flu vacciantion for are selected based on which virus strains are circulating, how they are spreading and good the current vaccine protects against new flu strains.
    There are 130 flu centres around the world that keep an eye on the flu viruses that are around and how they spread. These centres also take samples of the flu strains that they find and send them to a lab to find out how nasty they are. They pick out the strains of virus that are most likely going to infect lots of people around the world in the new season.

    The flu vaccine that is available each year contains protection against the 3 most common flu strains that are dangerous for humans (some viruses only affect animals). The World Health Organization makes a recommendation about what virus you should make a vaccine for, but it’s up to each individual country to make the final decision!

    A vaccine is pretty much a dead virus (scientists kill it, so it can’t cause disease) that you get injected into your body. Your immune cells will ‘see’ it and remember it. If you ever do get infected with the real virus (the one that is alive and cause disease), your immune system will immediately recognize it and attack it!

    0

Comments