Flu vaccine helped stifle worst cases

Report shows better prevention compared to previous outbreak.

CDC sees success rate of 55% in prevention of acute respiratory illness that would result in child needing visit to doctor’s office.

This season’s flu vaccine was particularly well-suited for children, the U.S. Centers for Disease Control and Prevention said, preventing many of the most severe infections.

Overall, the shot prevented about 45% of infections during the current flu outbreak, a CDC report stated. The 2019-2020 flu season started earlier than normal and appears to be lingering longer, after a second strain of the virus began circulating late in the season.

“For the influenza B that started off strong this season, and is severe in kids, the vaccine is working against that strain even though it’s different from what’s in the vaccine,” said Brendan Flannery, the CDC’s lead investigator for the Flu VE Network. “We are still referring to the vaccine as a good match, but we point out that for some people the vaccine doesn’t protect well.”

The effectiveness of the influenza vaccine is often hit or miss, since public health experts design it each year based on projections for which strains will emerge and how they may have mutated from the previous season.

An interim report from the CDC suggests the effectiveness of this year’s immunization falls somewhere in the middle of the 40% to 60% protection normally seen when the vaccine matches up well against the circulating strains.

This season’s outbreak has been marked by a unusually high level of doctor’s office visits for influenza-like illness, accompanied by an unexpectedly low rate of deaths. That may be because the predominant early strain circulating in the U.S was influenza B, which seems to hit children the hardest, while the elderly are most likely to die during a normal flu season.

High rates of the flu have also raised concerns that the virus will be mistaken for, or mask cases of, COVID-19, which has infected tens of thousands in China but largely spared the United States.

The CDC has set up surveys in several large U.S. cities to test for the new virus.

Flu levels are still elevated across the country and severe illnesses, including hospitalization rates for children and teenagers, are higher at this point

than any recent years.