Have you gotten your flu shot yet?
Public health experts say it’s never too late to make the annual pilgrimage to the doctor’s office, minute clinic, or whatever other pop-up inoculation station you can find in the hopes of preventing the flu.
But they pine for the day they don’t have to waste their breath reminding people to get a flu vaccine every single year.
That may be possible with the development of a universal flu vaccine, a shot that would cover multiple strains of the virus so scientists don’t have to play a guessing game, predicting which varieties of the ever-mutating flu will be prevalent in a given season.
While that’s a start, experts say even if the new funding passed it’s a drop in the bucket in what it will likely take to bring about a vaccine that could attack one of the world’s stickiest public health problems. But between the toll of the seasonal flu and the threat of a global pandemic, a successful universal vaccine could do a world of good for public health, despite the cost.
The flu and its vaccine
In order to survive, viruses depend on finding hosts, more-or-less hijacking those hosts’ cells, using them as Xerox machines to replicate, then forcing their host to cough, sneeze, vomit or otherwise introduce virus cells to new hosts where the process restarts.
The flu vaccine, first in wide use in the 1940s after the the flu virus was identified in 1933, is designed to help the human body create antibodies so the immune system can recognize and fight the flu.
Think of the flu virus like a piece of broccoli, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota: it’s got heads, and it’s got a stalk. The heads change as the virus mutates, while the stalk remains relatively stable.
The current vaccine uses a technique that targets the virus’ hemagglutinins — heads — which can change quickly as the virus evolves. That makes fighting the flu with current vaccines hard. You can hamper its ability to infect people by targeting the right strain in a particular year — if you correctly predict which strain will be a problem — but it’s liable to change.
“That head is constantly changing. Some years it’s changing a little, some years it changes a lot,” Osterholm said.
In a good year, the flu vaccine is thought to be about 40 to 60 percent effective, said Kris Ehresmann, the director of the infectious disease division at the Minnesota Department of Health. Compare that to most childhood vaccines, which are 85 percent to 95 percent effective, according to the World Health Organization. (Despite the flu vaccine’s shortcomings, almost everyone over 6 months of age is recommended to get a flu shot every year.)
The key this year, as every year, is to get as many people as possible vaccinated so the virus can’t spread as effectively. Minnesota’s flu vaccination rate hovers around the 50 percent mark, among the highest rates in the country, according to the Centers for Disease Control.
Last season, the predominant strain was H3N2, a strain that tends to be more dangerous for the elderly, Ehresmann said, which contributed to an uptick in flu hospitalizations — more than 6,000 all season, with more than 400 deaths.
That’s bad, but it could be worse. Last year’s virus represented a seasonal variety. The big fear is a pandemic, which happens when a new animal influenza virus mutates and infects humans. In the last century-or-so, there have been four pandemics: the Spanish influenza in 1918, and pandemics in 1957, 1968 and in 2009.
In the 1918 pandemic, an estimated 50 million to 100 million people died globally.
“Another flu pandemic is going to hit,” Osterholm said. “We worry every year about regular flu, but equally important, if not more important, is the next time a major influenza strain changes. It’s going to create potentially another 1918-like experience.”
In theory, the universal vaccine would be engineered in a way that would make it much more effective than current vaccinations.
Instead of targeting the virus’ ever-changing heads, the idea behind a universal vaccine would be to target something more consistent across flu strains. That would help deal with the issue of variability in flu virus strains by season. And because it would be effective against multiple strains of flu, people may not need to get flu shots every year anymore — in itself a public health plus.
Eliminating all those trips to clinics, where there’s lots of sick people and thus, lots of germs, could also have positive effects at the population level by exposing that many people to fewer germs.
All that sounds pretty good. But it’s also a ways off. While a universal flu vaccine is possible in theory, there’s still a lot that scientists need to learn.
Vaccines are currently in development. One in clinical trials, M-001, includes nine pieces of protein thought to be common across flu strains, according to Scientific American. The vaccine is designed to prompt both T- and B-cell immune responses, compared to just B-cell responses a typical flu vaccine would set in motion. B-cells identify strains based on shape, while T-cells use different characteristics.
Participants in the trial will receive the traditional flu shot in addition to M-001 as a protective measure, but the hope is that the new vaccine will prove effective on its own, Scientific American reports.
There are still details to be hammered out in the science. Besides the matter of what part of the virus you target, there are other complexities. For example, research shows the way people’s bodies fight the first flu they encounter primes the way they fight subsequent strains. The degree to which that could affect a universal vaccine’s effectiveness remains unknown.
But researchers are hopeful. Dr. Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases told STAT that he predicts scientists will make progress toward a better flu vaccine in 2019, better understanding how well vaccines that target multiple strains of flu might work.
In an audit of flu vaccine released in 2012, Osterholm and his team at the University of Minnesota cited the expense of developing new vaccines, bringing them through the clinical trial process and getting them to market as a major barrier to a better flu vaccine. They recommended the government collaborate with pharmaceutical companies, investors and academics to bring such a thing to fruition.
The Bill and Melinda Gates Foundation is backing research efforts, and the NIH has made the development of a universal vaccine a priority, Osterholm said.
In February, the National Institute of Allergy and Infectious Diseases released a strategic plan outlining its goals to better understand transmission of the flu, human immune response to the virus, as well as developing a vaccine that is 75 percent or more effective.
“There’s a lot of research that’s needed. It’s just the beginning,” Osterholm said.