After a flu season that hit hard in Australia and the United States, scientists are trying to see what lessons can be applied to the vaccine for next winter’s season.After a bad flu season in the Southern Hemisphere last fall, many in the healthcare community in the United States had braced themselves.
“Many of us anticipated that we were going to have a flu season that was on the severe end of the spectrum. It certainly was and it certainly continues to be,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center in Tennessee, told Healthline.
But even with the knowledge of Australia’s flu season, the flu still hit hard in the United States.
“Most of us were bracing for an onslaught, but it’s still a siege even if you know it’s coming,” Stephen Morse, PhD, a professor of epidemiology and an influenza expert at Columbia University in New York, told Healthline.
Experts say this year’s flu season has probably peaked, or at the very least plateaued. The U.S. Food and Drug Administration (FDA) has already started work on next year’s vaccine.
Preliminary reports on the effectiveness of this year’s vaccine suggest there was a 25 percentlevel of effectiveness against the H3N2 strain. For those aged 65 and older, the vaccine was only 17 percent effective. In older children and adults under 65, the effectiveness was even lower.
In a statement, FDA Commissioner Dr. Scott Gottlieb says efforts are underway to see what can be done to improve effectiveness for future vaccines.
“We’re striving to better understand why we saw reduced effectiveness of this year’s influenza vaccines against one strain of influenza A, called H3N2. It was this strain that caused much of the influenza-related illness this flu season,” he said.
Schaffner says there are obvious lessons to be learned from this year’s flu season.
“The paramount lesson is one that we already knew but it was painfully reinforced: Science needs to provide us a better influenza vaccine,” he said.
Meetings start early
Twice a year, the World Health Organization (WHO) holds a meeting to plan for the upcoming flu seasons in the Northern and Southern hemispheres.
The FDA and the Vaccines and Related Biological Products Committee then meet to discuss the WHO’s recommendations. This occurs more than six months before the flu season is due to begin.
“It seems early, but it needs to be done enough in advance to allow time for scale-up, production, and distribution of the vaccine. If nothing else, it engages people at a time of peak motivation. In recent years, with the benefits of experience and improvements in the system, the recommendations have usually been on target, and this isn’t generally the weakest link now,” Morse told Healthline.
So can health authorities do anything to make next year’s vaccine better?
It’s possible, experts say, but will require moving away from creating the flu vaccine using chicken eggs.
“In the short term, I think we do need more agile and easily scalable production methods that don’t depend on the venerable time-honored egg, and even so there’s still room for improvement. Even if it’s not the egg’s fault, we still need newer and more readily adaptable technologies, ” Morse said.
In Australia’s record-breaking flu season last year, the H3N2 strain dominated. It’s believed this was due to the manufacturing process.
“One big problem with the H3N2 component of the vaccine is that this flu strain changes significantly while it is being prepared for egg-based vaccine production. These changes can result in the vaccine virus differing from the H3N2 out in the community during flu season. This is on top of the virus changing as it moves through people, between countries, and around the world,” Ian Mackay, PhD, associate professor at the University of Queensland in Australia, told Healthline.
After their flu season, the Australian government brought in new initiatives offering free vaccinations for those most vulnerable to influenza.
If the United States has anything to learn from the Australian experience, Mackay says, it’s the importance of spreading the correct vaccination message.
“Vaccination is important but is under threat from a few very loud people with no expertise and little understanding of the safety or science,” he said.
“Communication programs that make clear the benefits and the realities of flu vaccination, especially among those at greatest risk from serious disease, may help the community separate fact from increasingly shrill forms of vaccination fiction. These messages need to reach as many as possible in as many forms as needed,” he added.
In the United States and elsewhere, one thing manufacturers have done to try and improve the vaccine is to offer a “stronger” vaccine for those aged over 65. The high-dose vaccine is four times the amount of a conventional vaccine, and performs better than the conventional vaccine for those aged over 65.
Schaffner notes this has raised questions as to why such a strong vaccine couldn’t also be used in younger people.
“I think there’s something to be said for that: Why don’t we study these vaccines in younger populations also? It may just be that more punch actually elicits a greater and perhaps more effective immune response. It’s worth studying,” he said.
Despite its flaws, Schaffner insists much is going right in the response to influenza.
“The WHO has created an international influenza surveillance network that has been enormously improved scientifically over the last 10 to 15 years. The capacity to detect new influenza strains, new variants that might become pandemics, are much enhanced, because those viruses are being detected much more quickly,” he said.
As the FDA continues to work with public health agencies in preparation for next year’s flu season, Schaffner says there’s one obvious way to better prepare for next year.
“I think there’s room for improvement in how vigorously providers recommend vaccines. Some vaccine is better than none, because influenza is a very serious illness. I don’t want providers to recommend the vaccine. I want them to insist on it,” he said.