How close is the world to having a universal flu vaccine?
The fast and successful development of COVID-19 vaccines has generated hope for new and effective vaccines for other infectious diseases, including influenza.
Moderna, which developed one of the first two COVID-19 vaccines authorized in the United States, announced in January that it was expanding its messenger RNA vaccine portfolio to develop vaccine candidates against HIV, Nipah virus and seasonal influenza.
Scientists have long sought not only better seasonal influenza vaccines, but also a universal influenza vaccine that could offer protection against all strains of the virus for more than just one season — and perhaps even a lifetime.
Experts agree that vaccination remains the best tool for fighting influenza, even as other mitigation measures in the age of COVID-19 have demonstrated that they can slow transmission, but protection from seasonal influenza vaccines in a good year is only 40% to 60%.
We asked Aaron E. Glatt, MD, FACP, FIDSA, FSHEA, chairman of medicine, chief of infectious diseases and hospital epidemiologist at Mount Sinai South Nassau in Oceanside, New York, and professor of medicine at the Icahn School of Medicine at Mount Sinai, how close he thinks the world is to having a universal influenza vaccine and what it might look like.
It is unclear how long it will be until we have a universal influenza vaccine. I suspect several years, but that is a guess. Inactivated influenza virus vaccines have been in use for more than 70 years, with no major changes in the underlying technology. However, this year — because of COVID-19-related reasons — influenza illness is at historical lows, we fully expect that to change when regular masking and social distancing are a thing of the past.
Every year, we gather the troops and try to vaccinate our patients, medical staff and employees against influenza. The amount of effort involved, costs and vaccination fatigue/vaccination hesitancy make this a continuous uphill battle. Wouldn’t it be great if we could just vaccinate one time for influenza, and it provided lifetime immunity? Well, we are getting closer to that reality.
Several recent publications provided new cutting-edge information on this critical subject. These papers support further development of candidate vaccines that target the hemagglutinin stalk — rather than the head — of influenza viruses as part of a universal influenza virus vaccine strategy.
An interesting analogy has been brought forward that nicely explains the concept. To put this into easy-to-understand terms, imagine an ice cream cone. Imagine that the cone represents the stalk of the influenza virus, whereas the ice cream represents a hemagglutinin particular to an influenza strain. You don’t want to be exposed to either the cone or the ice cream because that means you are potentially infected with virus.
The current vaccines essentially prevent influenza by trying to recognize the “ice cream” — or different hemagglutinins — on top of the cone and preventing/ameliorating the infection as a result. However, it does not recognize any other cones with different ice cream on them — ie, other influenza viruses — and you are enticed/infected by them. Clearly, this is not a very efficient system.
However, this new potential universal vaccine can recognize the cone itself — regardless of what ice cream/hemagglutinin is on top. Hence, by recognizing the stalk (“cone”), you prevent any ice cream/influenza virus from enticing/infecting you.
If this concept truly works, this would be a major paradigm shift in our approach to influenza vaccination.
- Bernstein DI, et al. Lancet Infect Dis. 2019;doi:10.1016/S1473-3099(19)30393-7.
- Nachbagauer R, et al. Nat Med. 2020;doi:10.1038/s41591-020-1118-7.
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