Adults Are More Flu Less Than They Think


While it may seem like the flu is an annual problem, odds are adults are blaming the wrong bug. The reality is that flu resistance gets better with age. Once adults are more or less over 30, they get the flu far less than most people think.

A new British study suggests that the typical adult over 30 only gets the flu virus every five years, on average. In spite of the insistence on getting flu shots every year, most adults (except seniors or others with impaired resistance) withstand the flu on their own. While adults will often feel ill more often than this, it turns out other “flu-like” bugs are really to blame.

“For adults, we found that influenza infection is actually less common than some people think,” according to Dr. Steven Riley, from the Imperial College London, who was the study’s senior author. Citing the new research on flu occurrences, the researchers “found that influenza infection is actually much less common than some people think,” Riley added.

Young people do get the flu more often; typically, they are ill with a flu virus every other year. This is probably because of exposure to large numbers of people through school, socializing, etc.

The international research team included scientists from London, China and the United States. Their results, which are being published Wednesday in PLoS Biology, explain their study using blood samples from volunteers in southern China. The team assessed the levels of antibodies from nine different strains of flu that circulated there between the years 1968 and 2009. They studied strains that had spread widely around the world, including Europe and the U.S. According to Dr. Adam Kucharski, who worked on the research team, this was the first time anyone tried to reconstruct “a group’s history of infection from modern-day blood samples.”

From the blood test results, the investigators concluded that children get the flu virus every other year on average. However, the scientists think adults are prone to get flu infections become less frequently as they move out of early adulthood. From age 30 on, adults typically get influenza bugs about two times per 10 years.

So what do people have when they think they are suffering from flu-like symptoms? One theory the scientists espoused was that “symptoms could sometimes be caused by common cold viruses, such as rhinovirus or coronavirus.”

The researchers hope that gathering this sort of lifespan data will help experts better understand who is at risk of infection. They also hope to determine how often, as well as how far, the flu strains spread through communities. Furthermore, they are trying to analyze how people might build up their immunity to different flu strains over a lifetime of flu infections.

Riley is cautious to over interpret the findings adults are more flu less than they think. They plan to conduct a similar study in the United Kingdom soon to see if the findings apply there as well. The hope is to see if there are reproducible patterns and whether this kind of analysis could lead to a more sophisticated vaccine protocol.

By Dyanne Weiss

Web MD