adapted from "Strategy May Improve Seasonal Flu Vaccines"
NIH Research Matters
Flu viruses constantly change, or mutate, as they circulate in nature. Seasonal influenza vaccines need to be updated each year to match the new strains. Scientists monitor flu strains circulating around the globe to predict which three or four strains will be most common during the next flu season. To allow enough time for the vaccine to be made, the strains must be selected more than six months before the influenza season begins. Sometimes, an unexpected strain shows up or starts too late to be included in the vaccine. This happened during the 2014-2015 flu season. That season's vaccine was less than 20% effective at protecting against influenza infection.
A research team led by Dr. Yoshihiro Kawaoka at the University of Wisconsin-Madison developed a way to predict flu mutations before they occur in nature. The scientists looked at samples of naturally occurring human H1N1 and H3N2 influenza viruses from different flu seasons. They created various versions of these viruses by making random mutations to them. The scientists wanted to know if these mutations could change the naturally occurring viruses so much that the vaccines, created months earlier, would become useless. Seasonal flu vaccines are currently developed and evaluated, in part, based on their ability to induce production of antibodies to current flu strains. If the researchers could understand the implications of the mutations to the flu strains, they could make better predictions about vaccines. They could anticipate how the strains would change. In that way, they could look into the future and know with greater confidence which strains would be circulating in flu season, allowing researchers to develop vaccines designed to produce antibodies to the those strains.
The researchers mixed these mutated virus collections with antibodies targeting the flu viruses the study began with. Mutations in some strains allowed the virus to replicate despite the presence of the antibodies. These viral strains continued to replicate and mutate. If such changes occurred during natural infections, vaccinated people might not have the right antibodies to fight the mutated strains.
To test whether they could accurately predict how viruses would mutate, the scientists compared the mutations they created in the lab to those that occur naturally. They found that their mutations matched how these viruses evolved in nature.
Then, the researchers used the lab-developed viruses to assess/check/investigate whether the viruses would be detected by the immune system similar to the way naturally created viruses do. The researchers tested the mutated H1N1 viruses against the naturally occurring H1N1 influenza. Nearly all the viruses replicated efficiently in the test subjects.
This laboratory-based approach could help researchers predict which viruses have the potential to cause future epidemics, and thus guide which strains to include in seasonal flu vaccines. "This is the first demonstration that one can accurately anticipate in the lab future seasonal influenza strains," Kawaoka says.
10
What is the problem the author refers to in the article?
A.
the challenges of tracking flu strains around the world
B.
the lack of funding to produce seasonal flu vaccines
C.
the difficulty in obtaining samples of human H1N1
D.
the risk of unexpected flu strains causing epidemics