How effective are flu vaccines? Does it lose its effectiveness over time? And is it still practical to get a flu shot?
This may be the questions bugging you especially after hearing a report that the malaria vaccine of GlaxoSmithKline was proven in a study to lose potency over time, despite having a bolster shot.
Malaria Vaccine Brouhaha
Glaxo PLC’s malaria vaccine is reputed to be the most advanced in the world, estimated to be superior to any vaccine by at least 10 years. It has taken nearly 30 years for the British company to develop the vaccine against the disease which is caused by a complex parasite.
Yet clinical trial results showed that after four years the level of protection given by the vaccine drops to just 36 percent. The results of said study were published in the medical research journal the Lancet.
It should be noted that the scientists who did the study admitted that the vaccine would still benefit children in Africa, where malaria is widespread.
Which leads us to the questions posed earlier— how effective are flu vaccines? Will a flu vaccine lose its effectiveness over time? Moreover, would the decline in the potency of flu vaccines be a good enough reason not to get a flu shot?
Flu Vaccine Potency May Decline
Yes, like vaccination against malaria, the effectiveness of flu vaccines may decline over time. In fact, Glaxo also recalled a four-in-one flu vaccine recently because it found out that the potency of the flu shot can decline over time.
The company’s Flulaval Quadrivalent Thimerosal-free vaccine is designed to provide protection against four strains of the flu virus. Yet Glaxo admitted it cannot ensure suboptimal protection in people who had received the said vaccine in the fall.
While flu vaccine can lose its potency over time, this should not in any way give you an idea to skip your annual flu shots.
Anti-flu vaccination groups have criticized that flu vaccines are not really effective in preventing flu. And most of them would raise the issue of declining potency of flu shots as another reason to discourage the public from getting vaccinated against the flu virus.
Level of Protection
Yet health experts agree that despite these perceived flaws in flu vaccinations, a flu shot is still the best way in reducing the risks of getting infected with the flu virus, and eventually getting sick.
The effectiveness of a flu vaccine may vary. The Centers for Disease Control and Prevention that in past flu seasons, a flu shot is up to 71 percent effective in lessening flu-related hospitalizations among adults, and up to 77 percent effective among those who are 50 years old and above. Among children, a flu shot can reduce the risks of getting the flu by 74 percent.
There was also a similar study published in the Lancet journal in 2011 suggesting that the level of protection given by existing flu vaccines is not as potent as we think it is. The study conducted by a US research team and funded by the Alfred Sloan Foundation showed that of the more than 5,000 studies from 1967 to 2011, only 31 studies provided enough evidence on the efficacy of flu vaccines.
This issue, expectedly, was raised by many anti-flu shot websites. But the authors of the same study clarified the issue, explaining that their data strongly suggests that influenza vaccines can provide a moderate level of protection.
The doctors added that the current flu vaccines will remain to have a significant role in reducing influenza morbidity and hospitalizations until more interventions are made available. They also acknowledged the track record of safety as well as moderate efficacy of flu vaccines.
Increasing Flu Shot Potency
If you want to increase your level of protection against flu, then you might want to ramp up your workouts.
Numerous studies have proven that being physically fit can improve immunity and increase the potency of vaccines against flu. In 2009, an experiment showed that regular brisk walking enabled sedentary and older adults to improve their aerobic fitness and more importantly, increase their influenza antibody counts.
A more recent study conducted by researchers at Iowa State had young and healthy volunteers jog at a moderate pace for 90 minutes or ride a bike 15 minutes after getting their flu shot. Others in the experiment sat quietly for an hour and a half after receiving their flu vaccine. The researchers then checked for blood levels of flu antibodies a month after the experiment.
The findings of the study showed how effective exercise is in improving the efficacy of the flu shot. Those who exercised after receiving the flu vaccine doubled the antibody response of the sedentary group. Moreover, they were found to have higher levels of immune system cells that aid the body in fighting off flu virus infection.
Clearly, flu vaccines still offer the best protection against the flu virus. While flu shots in CVS or Kroger are not foolproof, experts agree that it is still better for people to be vaccinated against flu viruses than have no protection whatsoever against the disease.