They found that whichever strain a person got exposed to during his/her first infection with flu virus as a child determined which flu strain he/she would be protected against during a future infection.
Commenting on the findings of the research, lead researcher of the study, Dr. Michael Worobey said that the year in which people are born can "ridiculously predict" their immunity from a particular strain of flu or how vulnerable they are to a strain of flu, NBC News reported. "If later in life you encounter another subtype of flu virus, one from a bird. that your immune system has never seen before but whose proteins also are of a similar "orange" flavor, your chances of dying are quite low because of cross-protection", he said.
The researchers say that the new findings could help doctors actually predict which age groups are going to be at higher risk for infection from flu and severe illness in future flu pandemics. The results, to be published in Science on November 11, could hold important clues for public health measures aimed at curbing the risks of a major flu outbreak. The two strains are a top concern for health officials because they have already caused severe illness and death, and they could eventually mutate and rapidly spread among humans.
Scientists have always wondered why some people are hit harder - or even killed - by the flu but a new study finds that the year you were born may hold the key to this mystery.
"In this analogy, let's say you were first exposed to a human "orange lollipop" flu as a kid", Worobey said. Those born after 1968 appear to be protected against the second group.
"We have some kick-ass protection against one or the other", Worobey told the Telegraph. They call the phenomenon "immunological imprinting", and they believe it likely determines the type of protection your body has against the flu for the rest of your life.
Researchers found that the people in this study who were born before 1968 were less susceptible to a certain strain of the flu than those born in 1968 or later, because this older group had been more exposed to a similar strain as children.
In other words, researchers assumed that everyone's immune system would be defenseless against a new, widespread strain of the flu, she said.
"But if you were first infected with a virus from the "blue lollipop" group as a kid, that won't protect you against this novel, "orange" strain", he explained in a university news release. Note: material may have been edited for length and content.