This article was posted in February 2008 in regards to the numbers of people who were sick with flu despite getting a flu shot.
Find updated information:
- Review of Flu 2008 - 2009 (Influenza Diagnosis, Treatment, Tracking, Vaccines and More)
- Why Young and Healthy People Need Flu Shots.
Does it seem like everyone around you is sick with the flu? It's already late winter and it seems like more people than ever have been sicker during this flu season.
Even those who got a flu shot this year are getting sick. Stories about possible virus mutations or problems with the vaccine are running rampant. It's time to check in with a professional to get the real answers.
I interviewed Cynthia Morrow, MD MPH, Onondaga County (New York) Health Commissioner, and Assistant Professor of Medicine at SUNY Upstate Medical University, about the 2007-2008 flu season and why it seems so different to us patients this year:
Q: Dr. Morrow, why does it seem like there are so many more people than usual who are getting sick with flu this year?
A: Every flu season is different. In our region, the number of people suffering from the flu is higher than it has been in the last couple of years. That is true in other regions, too. One problem is that the vaccine developed for this year's flu season does not seem to be as good a match.
Q: Is that why even people who got a flu shot are getting sick with this year's flu?
A: That is probably one of the reasons. Each year's vaccine is determined at least six months before the start of the flu season in the Northern Hemisphere. Infectious disease experts predict which viruses are most likely to cause flu the following flu season. They do this because it takes that much time to develop the vaccine, then manufacture enough of it for the number of people who will want to be vaccinated with a flu shot.
The vaccine developed for the 2007-08 flu season is comprised of three different vaccines, for three different strains of influenza viruses, those that were determined in late 2006/early 2007 for this season. It turns out that across the United States many people are being exposed to a strain of virus that is not covered by the vaccine -- so some people are getting sick even though they were vaccinated.
Q: So this isn't a question of virus mutation. Instead it's a case of poor prediction?
A: Influenza viruses are inherently unstable and frequently change slightly -- something we call "drift." Making predictions about what will happen, so far in advance, isn't a perfect science. Fortunately, these predictions are usually quite accurate. Unfortunately, this year it appears that there is a significant mismatch between the strains covered by the vaccine and some of the circulating strains. It is important to remember that at least one of the common circulating strains IS covered by the vaccine.
Q: So was getting a flu shot this year a waste of time?
A: Absolutely not. One common strain that had been identified is covered by the vaccine. And those who are exposed to a slightly changed strain and who become ill, may still be partially protected. They are likely not to get as severely ill as they would have had they not received a flu shot.
Q: Is the flu hitting later this year than other years?
A: Each year the flu runs its own unpredictable course. Some years it hits earlier, in late fall. Other years it hits a bit later. Different parts of the country may see the flu at different times during the season. In this region, February is our peak month for flu activity. It's not unusual for the flu season to last into April in some areas of the country.
Q: If the flu season lasts into April, then is it too late to get a flu shot?
A: It depends on where people live. As long as there is still flu activity, a shot will protect from the flu. People should check with their primary care provider to see if it makes sense for them to get a flu vaccine. Patients in different parts of the country will get different answers depending on the flu cycle in their location.
Q: Is the shot effective against flu immediately?
A: It takes about two weeks for it to be effective. If you get a flu shot today, expect it to protect you two weeks from now.
Q: Is it possible to catch the flu from getting a flu shot?
A: No one catches the flu from an inactivated flu shot although some people may have a low grade fever and mild symptoms as a reaction to the vaccine.
If a person gets a viral illness after getting the flu shot, that is simply coincidental. People often decide to get a flu shot when others around them seem to be sick. Sometimes they are exposed to the flu or a cold around the same time they get the shot. Then they get sick within days of getting vaccinated and think the shot caused it. But, it didn't. It's just coincidence.
Q: Any last words of advice, Dr. Morrow?
A: Do your best to protect yourself and your loved ones from getting the flu.
A flu shot is a good idea for everyone, but most importantly for those who are most at risk such as those who are over age 50, people who have other illnesses, pregnant women, health care or daycare workers, or children between the ages of 6 months and 5 years.
It is very important to remember to wash your hands carefully and frequently, to cover your nose and mouth if you sneeze or cough, and to stay home if you do become ill.
Finally, if you do get the flu, contact your primary care provider immediately. There are anti-viral medications that may help to alleviate the worst effects of the flu and can even be used to prevent influenza in some cases.