This flu season has been particularly grim. More people are dying of the flu than medical professionals would expect at this time of the year. One in 10 people who died during the fourth week of January died of pneumonia and influenza, and 84 children have also died so far this flu season. The number of people seeing a health care provider for flu symptoms is almost as high as 2009, when the flu hit pandemic levels.
One reason for that? There’s little faith that the vaccine will work. This year, initial estimates had suggested that the vaccine may be just 10 percent to 17 percent effective against H3N2, this season’s most common strain. That’s based on interim reporting from Canada and the final effectiveness rate in Australia for this strain.
But those figures turned out to be an underestimate. The numbers on the effectiveness of the shot among Americans, released Thursday, reveal that for all ages, the vaccine is 25 percent effective against H3N2. For children ages six months to eight years, it was even more effective against the strain, at 59 percent.
However, taking into account combined effectiveness of all of the strains, the vaccine is just 36 percent effective — lower than the usual 40 to 60 percent effectiveness of past shots.
Arguably the biggest reason that Americans don’t seem to take the flu vaccine seriously is that it simply doesn’t live up to our expectations for what a vaccine is, and how it should work, said Dr. Pat Salber, founder of the healthcare blog The Doctor Weighs In.
One or two shots that confer lifetime or years-long immunity at near 100 percent effectiveness is the model we have for serious illnesses like measles, mumps, rubella and other viruses. But the flu vaccine, with its variable effectiveness and weaknesses that require people to go in year after year, presents a compliance barrier for busy people.
“We know this from taking pills,” Salber said. “If I give you a pill and you only have to take one a day, you’re going to do a pretty good job. If you take it twice a day, your compliance falls off. If you have to take three pills a day, I can guarantee you won’t get three pills in a day on most days.”
“I’m disappointed [in the flu shot]. I think we could do a little bit better.” Eric A. Weaver, researcher for a universal flu vaccine
Some flu experts hope that the severity of this year’s flu will provide a silver lining, motivating people to get the flu shot this year and in years to come. Typically, fewer than half of all Americans bother to get a flu shot in any given year, and the numbers are mostly concentrated among those who are uniquely vulnerable to the virus: children under 12 years old, and seniors over 65, said Dr. Arnold S. Monto, an epidemiology professor at the University of Michigan School of Public Health. This leaves out older children and young adults, who have the most opportunities to transmit the flu virus.
“Do we use enough vaccine to really cut down on the transmission? The answer is no, we really don’t,” said Monto.
But Eric A. Weaver, a scientist working on research for a universal flu vaccine at the University of Nebraska-Lincoln, agreed that there’s a fundamental problem with the flu vaccine as a product, and that keeps Americans away.
“When I teach about flu vaccine, I ask students, ‘Why do you need a new shot every year?’ They always answer, ‘because the strain changes from year to year,’” Weaver said. “But the other part of the answer is that by the time the next flu season comes around, you’re no longer protected because the flu vaccine is weak, even if the strain doesn’t change.”
Of course, public health experts are quick to point out that even flu vaccines with limited effectiveness are still worth getting, because they can both lessen the severity of your symptoms if you do get the flu and also prevent you from passing on the virus to people who are more vulnerable, like kids or the immunocompromised.
Weaver, who is currently testing his universal flu vaccine in mice, hopes that his research will one day provide lifetime protection in children who get the shot. Currently, yearly flu shots that are 50 percent effective are just not an attractive product for Americans, he said.
“I work on flu vaccines and I defend flu vaccines, but I’m not going to argue with somebody who says I’m not going to take it,” Weaver said. “I’m disappointed [in the flu shot]. I think we could do a little bit better.”
CORRECTION: Due to an editing error, a previous version of this story incorrectly stated that the vaccine effectiveness of the flu shot against H3N2 was 25 percent for people over 8 years old. In fact, that figure is for people of all ages.