A universal flu vaccine could offer protection against even unknown strains—but will another pandemic hit before it's developed?

By Leah Groth
Updated January 23, 2020
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There are tons of reasons to get a yearly flu shot: About eight percent of the entire US population (all 327.2 million of us) gets sick with the flu each year, according to the Centers for Disease Control and Prevention—and that's truly only an estimate. It's also extremely contagious (people with the flu can spread it to others via droplets from coughing, sneezing, and talking up to six feet away) and can be deadly (61,200 people died of the flu in 2018 alone).

And yet, less than half of adults and just over 60 percent of children got the annual jab during the 2018-2019 flu season. The reasons why range from people being hesitant about the effectiveness of vaccines, avoiding it because of a fear of needles, or simply forgetting or not having the time, but one thing is clear: Not enough people are getting the flu shot—and there are consequences.

That's where Netflix's new docuseries Pandemic: How to Prevent an Outbreak comes into play. The six-part series, which premiered on January 22, explores the possibility of a universal flu vaccine and why it would be so important to health, worldwide. "Influenza is very hard to predict," Syra Madad, DHSc, senior director of the Special Pathogens Program for NYC Health + Hospitals, pointed out in the documentary. "It takes one person—one host—to lead to a pandemic."

And a pandemic—the worldwide spread of a new disease—of the flu isn't unheard of: It was just 100 years ago that the Spanish flu of 1918 (H1N1 virus) wiped out 50 to 100 million people and infected an estimated 500 million people (one-third of the world’s population at the time) per the CDC. Considering the havoc it wreaked on the two billion inhabitants of earth a century ago, experts worry that our current world population of 8 billion could be devastated by a similar illness—mainly because we still haven’t found a fool-proof way to eradicate, cure, or even protect ourselves against the flu.

In fact, many experts believe we are due for another deadly pandemic. According to Dr. Dennis Carroll, director of USAID’s Emerging Threats Unit, featured in the show’s trailer, “When we talk about another flu pandemic happening, it’s not a matter of if, but when.” Some believe that “when” is actually now with the recent coronavirus outbreak rapidly spreading across the globe, predicting that the deadly virus that originated in Wuhan, China could be as deadly as the Spanish flu—which only adds to the reason why a universal flu shot is at the forefront of many doctors' and scientists' minds.

What exactly would a universal flu shot look like?

Right now, you're supposed to get a flu shot every year—and that flu shot really only protects you from the influenza viruses that research predicts will will be the most common during the upcoming season, according to the CDC. Most flu vaccines protect against four viruses: Two influenza A viruses (H1N1 and H3N2) and two influenza B viruses. 

A universal flu vaccine, however, would provide a broader protection against different classes of the influenza virus, Albert Shaw, MD, PhD, an infectious disease expert at Yale Medicine tells Health. In that case, "the composition of the vaccine wouldn't need to change every year, so there could be protection even against a previously unknown pandemic strain." That protection would also be long-lasting, so you wouldn't need to get it every year (though, researchers don't know exactly how long it will last until it's formulated), and available to children, adults, and the elderly population.

The National Institutes of Health also has its own criteria a universal flu vaccine would have to meet: It would have to be at least 75 percent effective, protect against group I and II influenza A viruses, have durable protection that lasts at least one year, and be suitable for all age groups.

That sounds fair. So why isn't there a universal flu vaccine yet?

To be totally honest, the flu is extremely complicated. "The influenza virus has a remarkable ability to mutate the composition of proteins such as hemagglutinin that are important targets of a protective immune response," says Dr. Shaw. "This is why the 3 or 4 strains of influenza virus in the annual vaccine frequently change from year to year, and last year’s vaccine may not provide the best protection against this year’s influenza."

The influenza virus can also occasionally undergo a marked change to a new pandemic strain where previous immunity may not be effective, he adds. “Such pandemic strains frequently emerge from animal reservoirs for the influenza virus such as birds or pigs and are difficult to predict in advance.”

Of course, that doesn't mean scientists aren't trying to come up with a universal vaccine—in fact, Dr. Shaw explains that a lot of research has gone into understanding the immune response to the current influenza viruses and vaccines, in hopes of eventually finding a universal vaccine. "There are parts of the influenza virus that are well conserved across many different influenza strains, and these would be great candidates for a universal vaccine," says Dr. Shaw. "But the problem has been that these parts of the virus don't give a strong immune response, and a lot of work is being done to understand how to develop effective vaccines from these [parts]."

Confusing, right? Dr. Shaw says it's easier to understand one of the key parts of the influenza virus—hemagglutinin protein, which is integral to its infectivity—as having a structure similar to that of a lollipop, with a "stem" and "head" portion: "The head of the protein is highly variable from strain to strain but the stem sequence stays pretty consistent across many strains," he says. "Current vaccines mainly result in antibodies against the head portion, and one approach in clinical trials tires to generate antibody protection against the stem."

So, that means a universal flu vaccine is in the works?

Yes! The National Institute of Allergy and Infectious Diseases (NIAID), a division of the NIH, is currently in the first stage of human testing of H1ssF_3928, a universal flu vaccine. Results on the safety and efficacy of the vaccine should be available in the next few months—but that means that it likely wouldn’t be available to the general public for another decade. 

The vaccine, currently being tested at the NIH Clinical Center in Bethesda, Maryland, is designed to “teach the body to make protective immune responses against diverse influenza subtypes by focusing the immune system on a portion of the virus that varies relatively little from strain to strain.” In February 2018, researchers at the NIH unveiled their agenda to develop a “universal” influenza vaccine, one that would provide long-lasting protection for all age groups from multiple influenza subtypes, including those that might cause a pandemic.

“Seasonal influenza is a perpetual public health challenge, and we continually face the possibility of an influenza pandemic resulting from the emergence and spread of novel influenza viruses,” said NIAID Director Anthony S. Fauci, M.D. “This Phase 1 clinical trial is a step forward in our efforts to develop a durable and broadly protective universal influenza vaccine.”

Jacob Glanville, PhD, Founding Partner, CEO, and President, of the privately funded biotech company, Distributed Bio, and who is featured in Pandemic, is also on a mission to develop a universal flu vaccine. His company’s journey is heavily featured in the Netflix documentary.

However, Glanville's company has yet to make it to the human testing stage mostly due to financial restraints—it's one of the main reasons he decided to participate in the show. “I am avoiding traditional funding, so this provided a platform for people to hear about us—private investors, governmental groups, foundations,” he explains via email. 

Still, clinical trials (and multiple forays into the world of a universal flu vaccine) is good news, not to mention something to look forward to for future generations. For now, though, it's important, if you're able, to keep protecting yourself (and others) with the yearly flu shot—no excuses.