As this season’s flu activity continues to slow down from its late-December peak, debate about the effectiveness of our current flu vaccines, particularly in preventing deaths among the elderly, has picked up steam.
Last Thursday, the U.S. Centers for Disease Control and Prevention (CDC) updated its estimates on the effectiveness of the 2012-2013 flu vaccine. The agency reported that the vaccine was only moderately successful this year in protecting people from the virus strains for which it was matched.
It was 47 percent effective for influenza A viruses (mostly H3N2) and 67 percent effective for influenza B viruses. (Not enough data was available to determine its effectiveness against a third strain, H1N1.) That meant that the vaccine had an overall effectiveness of 56 percent.
But among people aged 65 and older — the demographic group most at risk of being hospitalized and dying from complications of the flu — the vaccine was dismally inadequate. It was only about 27 percent effective in protecting older Americans from all of the flu viruses and only 9 percent effective in protecting them from H3N2, which was the strain that caused the most illness this flu season. In fact, those numbers were so low, they were deemed to be statistically insignificant.
The report’s findings, wrote its authors in an accompanying editorial note, "reinforces the need for continued advances in influenza vaccines, especially to increase protective benefits for older adults."
Not surprising
Nothing in the CDC’s report surprised Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP). For some time he’s been pointing out the inadequacy of our current flu vaccines and calling for a major research effort to develop better ones.
Last fall, for example, Osterholm and his CIDRAP colleagues published a comprehensive report that was three years in the making and involved more than 12,000 studies, meeting reports, interviews with experts and other documents going back to 1936. The report concluded that the current flu vaccine was “suboptimal” and that it was time to develop a truly effective and “game-changing” new vaccine.
“The thing that surprises me is why everybody is surprised” that the flu vaccine has been found to be so ineffective, Osterholm said in a phone interview late last week. Vaccine manufacturers have been making the flu vaccine essentially the same way for decades, he said, and because of that, its effectiveness stays the same.
“We are still putting, basically, a 1930s carburetor in a 2013 car,” he said.
Even when the vaccine is a good match to the virus strains that are circulating within a given flu season, its effectiveness tends to remain below 70 percent.
We expect childhood vaccines, on the other hand, to be 90 to 95 percent effective in preventing measles, pertussis and other diseases.
Adding to concerns about the flu vaccine’s ineffectiveness are recent findings from a multi-center European study that suggest its protection may wear off within three months.
“That’s challenging the whole notion of our immunization program — that you get vaccinated in the fall so you’re ready to go for the whole flu season,” said Osterholm.
A need for frankness
Osterholm wants public health officials to be more frank with the public about the limitations of the flu vaccine.
“What I worry about more than anything is the long-term credibility of science in public health,” he said. “Will people trust us if they don’t think that we’re being honest and forthright with the public data? Are we becoming nothing more than the anti-science people?”
Individuals — particularly the elderly and others at increased risk of developing serious and even deadly complications from the influenza — should still get an annual flu shot, he stressed, but health officials should “be honest about what it is. Stop trying to spin it.”
“I’m very willing to have people get vaccinated, even if it reduces hospitalizations in those over 65 by a couple percent,” Osterholm said. “That’s still a pretty damn cost-effective approach, given the cheap cost of the vaccine and its safety. But the problem is if we oversell it and make these statements that are just not true about how effective it is. Then we’re doing exactly what the anti-science people are doing.”
‘Where’s the program?’
Osterholm said he’s frustrated by how the CDC and other government health officials continue to talk about the need for a better flu vaccine, but don’t take any concrete action to actually get one developed.
“Where’s the program?” he asked. “Public relation wishes and good will isn’t going to get us one. We need a strategic and tactical plan. We have none. There is no international plan for moving forward with novel, game-changing vaccines.”
Meanwhile, influenza-related hospitalizations and deaths continue. According to the latest (Feb. 16) Minnesota Department of Public Health statistics, 2,784 people have been hospitalized with laboratory-confirmed influenza in Minnesota this season. And 148 influenza-related deaths have been confirmed in the state.
You can read last Thursday’s CDC update on the flu vaccine’s effectiveness in the Feb. 22 issue of the Morbidity and Mortality Weekly Report (MMWR). The agency will be issuing a final effectiveness assessment later in the year.