Every year I spend weeks and months encouraging reluctant individuals to get the flu vaccine, usually with some success. Then, as soon as the virus hits town, I start to get calls from patients and physicians that they were just diagnosed with the flu, even though they got the vaccine.
Rumors start to fly about new strains of the virus or concerns are raised about how the vaccine was stored or administered that might reduce its effectiveness, but the CDC reports that the vaccine is a good match for the circulating strains of flu.
So why is that? Why do some people get the flu despite getting vaccinated?
Flu vaccine effectiveness is highly dependent upon the competence or strength of the individual’s immune system. Many of the people at highest risk for getting the flu are those with weakened immune systems due to diabetes, old age or very young age, or weakened body systems such as those with heart, lung or nervous system disease. About half of these people may not respond to the vaccine well and remain vulnerable despite having been vaccinated.
Even healthy people may not respond well to the vaccine, though the odds are better – probably around 70 to 80 percent will be protected. Getting a sore arm or a raised red bump at the site of the vaccine, or getting the sniffles after nasal mist, means that you are more likely to have stimulated your immune system to protect you.
The good news is that your case of the flu is likely to be shorter and milder than if you didn’t have the vaccine. Vaccine is about 70 percent protective overall against severe disease and hospitalization.
Vaccine manufacturers are working to develop flu vaccines that are more effective and that will last through many flu seasons, but it will be a few years before those vaccines are fully tested and available. Adjuvants, which are additives put in vaccines to boost the immune response, may be the near-term answer.
If you come down with flu symptoms – fever, sore throat, body aches and runny nose – and you’ve had the vaccine, be sure to contact your doctor early on so that you can start on antiviral medication to further shorten the course of your illness.
And continue to get your vaccine yearly – there are good odds that your protection improves the more you are vaccinated, as not all of the vaccine strains change every year!