If you hate getting a flu shot every year, there may be some good news on the horizon.
Scientists at Cornell University are undertaking research into a single dose, long-lasting influenza vaccine.
Although it’s a long way off for use in humans, if successful the vaccine could mean only needing to be vaccinated against influenza every 5 to 10 years.
“Our goal was to make a single-dose vaccine that would protect against multiple strains of influenza. Some people like to call it a ‘universal vaccine,’ but that is too optimistic. ‘Broadly protective’ is a more reasonable and obtainable goal,” David Putnam, PhD, associate professor in the Nancy E. and Peter C. Meinig School of Biomedical Engineering at Cornell University, told Healthline.
“It would help greatly if the vaccine lasted for a significant period of time and not require a booster dose every year,” he said. “It will be more economically viable if the vaccine lasted 5 to 10 years.”
A changing virus
The flu virus can mutate and has a great tendency to change every year.
This can make developing an annual flu vaccine challenging.
“It’s looking into your scientific crystal ball and trying to predict the future,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, told Healthline.
“With the changing of the virus, what the experts have to do is anticipate 9 to 10 months in advance what the dominant flu viruses will be the coming winter and thereby creating a vaccine on an annual basis in anticipation of the changing influenza virus,” Schaffner added. “It’s a bit of a scientific gamble.”
Despite the changeable nature of the influenza virus, certain proteins within the virus remain constant every year.
The researchers from Cornell are taking one of those proteins and packaging it into a nano-size, controlled-release capsule in the hopes of creating a long-lasting multi-strain vaccine against influenza A.
The time-release capsules mimic a vaccine booster shot by releasing antigens over a period of time.
In experiments, mice infected with the influenza A virus had high antibody counts a month after vaccination with the new vaccine, compared with eight weeks for the current vaccine regimen.
After six months, the mice who were given the new vaccine survived a lethal influenza A infection.
Six months is roughly 25 percent of the life expectancy of a mouse, and Putnam is hopeful it could be long lasting in humans as well.
“Even if we have to give a booster shot every 10 years, like tetanus, that’s still very good,” Putnam said in a press release. “Theoretically it should last a long time.”
Although likely several years away from use in humans, if such a vaccine were successful, the implications for public health would be considerable.
“If we had a universal vaccine that gave you five years’ worth of prevention, we’d only have to use that one vaccine and we could vaccinate around the year. Every time someone had an encounter with the medical care system, whether a hospital, a physician’s office, a nurse, a pharmacist’s office… we could vaccinate them,” Schaffner said.
“We would not be limited to this crash program that we do every year trying to vaccinate people. We could do it in a cumulative fashion around the year,” he added. “It would change the whole way we administer influenza vaccine.”
Although the severity of influenza varies by the season, the estimates that the influenza virus has resulted in between 9 million and 36 million illnesses, 140,000 to 710,000 hospitalizations and between 12,000 and 56,000 deaths annually in the United States since 2010.
“There is no question we need better flu vaccines. Current vaccines aren’t nearly as effective as we’d like. It seems about 50 to 60 percent at best, even if the vaccine is a good match to the circulating viruses, and less for those aged over 60,” Stephen Morse, PhD, professor of epidemiology at the Columbia University Medical Center, told Healthline.
More research needed
Morse says a universal flu vaccine would be a game changer for public health, but he adds it’s still too early to tell if research like the study from Cornell will be a success.
“It’s interesting and seems promising, but years at best from the hoped-for universal vaccine. Many vaccines that gave great results in mouse testing fail in humans. It’s an old, if wry, joke among people in the vaccine field that they’ve been able to save many mice from dreaded infectious diseases or that if we were mice we’d have all these vaccines by now,” he said.
“Influenza is a particularly tricky one, because mice are generally resistant to most human influenza viruses, requiring “mouse-adapted” laboratory strains to be used,” Morse added. “So mouse protection alone is usually more a sine qua non [an essential element] than a predictor of the vaccine’s effectiveness.”
The Cornell researchers are just one of many teams of scientists working toward a universal vaccine.
Some universal vaccines have reached clinical trials in humans, and infectious disease experts say this is promising.
“After years of relative inactivity in influenza vaccine development, there are now a number of new, novel, and imaginative ideas finally being tried. That’s a hopeful sign,” Morse said.
Schaffner says he is cautiously optimistic that we will one day have a universal flu vaccine. He describes such an achievement as a “holy grail” innovation in public health.
“If somebody is truly successful (in creating a universal influenza vaccine), they would make the shortlist for the Nobel Prize consideration in my opinion,” Schaffner said. “The impact on the general literal health on humanity would be so enormous.
“Any way you measure it, influenza has an enormous disruptive impact around the world annually,” he added. “We would love to blunt if not reduce substantially the impact of this epidemic around the world. We would save many lives and save a lot of money.”