By Priyam Vora
The flu has claimed the lives of 54 children in U.S. so far in one of the worst flu seasons on record, experts say. A major reason for the severity of the 2014-2015 season is because the vaccine has become only 23 percent effective, according to the Centers for Disease Control and Prevention (CDC).
Compared to last year, the 2013-2014 flu season claimed the lives of 20 children through mid-January, according to CDC data reported by CBS News last year.
Experts say the shots are less effective because the strain of the flu picked for the vaccinations this year have undergone an “antigenic drift.” What they mean is that the flu viruses are constantly changing. It is a common occurrence for the strains in the genetic makeup of the virus to suddenly drift from the strains covered by the vaccine.
“It is much worse than the other years because of how early it started,” said Dr. Allison Bartlett, a specialist in pediatric infectious diseases at the University of Chicago Medicine. “Combine that with the vaccines not being as effective, the severity has increased.”
Throughout the year, influenza surveillance centers around the world keep an eye on influenza diseases in their respective countries. These centers then, send samples to major research laboratories around the world, including the CDC.
Based on the identified influenza virus risks, the CDC makes recommendations for which virus strains should be covered by the current season’s vaccines, which is ultimately decided by the U.S Food and Drug Administration (FDA).
“This year, however, the influenza virus unexpectedly ‘changed’,” said Dr. Poj Lysouvakon, a pediatrician at Comer Children’s Hospital.
Based on its initial observations and data collection, the CDC concluded that the H3N2 strain has undergone an “antigenic drift”. The “drift” means that there are changes in the genetic makeup of the virus that make the H3N2 strains that cause the virus different from the strain used months ago to determine the vaccine formulation.
According to a CDC press release, the increase in the risk of a severe flu season is the finding that roughly half these H3N2 viruses analyzed were drift variants.
“Consequently, the vaccine isn’t a good match for the prevalent flu virus that is currently causing these outbreaks in the country,” Lysouvakon said.
Another reason for the outbreak in the country is the early onset of the virus. Children, with less immunity to illness overall, are more vulnerable to flu than healthy adults.
While developing a new vaccine may seem like an obvious solution, it is not!
The recipe to create the vaccine starts early in February for the next season. Within the next six months, the experts develop the vaccine, run several tests and following a few modifications, they accelerate the manufacturing process and distribute the vaccine.
“It is tempting to think we can make a new vaccine but it’s not as easy as it sounds,” Bartlett said. “There are technological limitations.”
Predicting many months in advance which strains will be circulating in the coming flu season is a tricky assumption to make even if it is an educated process. However, health experts strongly insist that everybody, especially children and older people, get their shots as that can make flu symptoms less severe.
“Despite the mismatch between the strains in the vaccine and the strains circulating in the country,” said Lysouvakon, “flu shots still offer protection against the other less common strains of flu virus.”
Bartlett agrees. “Although it is too soon to predict, there might be a second spike of flu this season,” she said. “It is best to get your flu shots.”