Government seeks to rebuild trust after flu shot SNAFU

The problem? They could be completely wrong.

This season’s shot was only 18 percent effective against the most prevalent influenza strain, called A H3N2. The vaccine mismatch is drawing negative attention from Congress, putting pressure on the Food and Drug Administration and the Centers for Disease Control over their roles in selecting vaccine strains, and prompting calls for a more efficient process of flu-shot development.

The ineffective vaccine was rolled out during a devastating flu season. As of Feb. 6, the flu-associated hospitalization rate among seniors 65 and over is the highest since the CDC started tracking data a decade ago.

The World Health Organization, which broadly decides what influenza strains to concentrate on when each year’s vaccines are being developed, held a meeting in February and recommended three strains be covered in the next flu shot. The organization selects the strains based on influenza trends from the previous year and how well current shots protect against newly identified strains.

Unfortunately, influenza strains can mutate and change even before the flu shot reaches the public — as seems to have been the case with this winter’s flu.

Manufacturers use the WHO’s recommendation, which is typically adopted by the U.S. Food and Drug Administration, to develop the flu shot. The vaccine can protect against either three or four strains.

During the current flu season, which goes from October to March, the shot covered H3N2, but the strain drifted after the recommendation was made in February 2014.

The WHO included that virus strain among the three types of influenza recommended for the 2015-2016 season. An FDA advisory panel adopted the recommendation during a meeting last week, and the agency will make the final call.

However, there is no guarantee that the same problem of vaccine mismatch won’t happen again next flu season.

The recommendation must be made early in the year to give manufacturers enough time to make the shots, said Ofer Levy, MD, who works in Boston Children’s Hospital’s division of infectious diseases and teaches at Harvard Medical School.

Most vaccines are still created using the time-consuming method of chicken eggs. The manufacturer injects the virus strains into the eggs and incubates them for several days. The virus-containing fluid is then harvested from the eggs and used to make the vaccine, the CDC said.

“Manufacturers are being asked to deliver 100 million doses of safe, well-defined vaccines over two months’ time,” Levy, who sat on the advisory panel but doesn’t speak for the FDA, told the Washington Examiner.

But an active virus can shift and change between the time the recommendation is made and the shot is delivered, making that shot ineffective.

Ineffective vaccines have happened before. The virus has significantly changed four times over the past 20 years, Centers for Disease Control officials said before a House hearing earlier this year.

Levy said a way to make more effective vaccines is to speed up production.

“It could buy us more time before we had to commit to the decision” on which strains should be covered, he said.

Some groups are working on a universal flu vaccine that would be effective against more strains, but that is still years away, Levy said.

The flu shot process has drawn the attention of Congress. Reps. Tim Murphy, R-Pa., and Diana Degette, D-Colo., high-ranking members of the House Energy and Commerce Committee, sent letters on Monday to several agencies questioning their preparedness for this flu season.

One letter asked the U.S. Food and Drug Administration what efforts it has made to ease the approval process for flu vaccines. Another asked the CDC how it could respond to a mismatched influenza strain.

Despite the shot’s ineffectiveness, Levy recommended the American public still get the flu shot, which can still offer protection against a virus that kills thousands of people.

“It is a safe vaccine,” he said.