The technology used in two of the coronavirus vaccines authorized by the Food and Drug Administration may enable scientists to develop flu shots in record time but also make inoculations that could be more effective and protect against numerous flu strains for years at a time.
The messenger-RNA technology -- used in the Pfizer and Moderna coronavirus vaccines -- would be a leap forward for flu shots, some of which still rely on a process developed in the 1950s involving chickens, petri dishes and dead viruses.
Researchers are hopeful that the success of those coronavirus vaccines will grease the wheels for mRNA flu shots and help expedite what is typically a lengthy process.
"It's a very obvious progression given the success of the covid-19 vaccine to move right to flu," said Andrew Pekosz, a professor of microbiology at the Johns Hopkins Bloomberg School of Public Health.
But researchers say the development and approval of an mRNA flu shot may take some time.
The idea that scientists can use messenger RNA for medical therapeutics is not new. Flu shots using mRNA technology have been in development for years.
In 2018, for example, Pfizer and BioNTech announced a partnership to start developing an mRNA vaccine that would prevent influenza. Moderna is working on a number of different mRNA vaccines, including one for the flu.
So with a pressing need spurred by a global pandemic and billions of dollars in funding for vaccine development, scientists were able to repurpose their knowledge of mRNA to develop coronavirus vaccines.
Currently, the most common influenza vaccine that is available in the United States is manufactured using an inactivated, or killed, virus and administered via a shot in the arm. But there is also a vaccine that uses a live, but weakened, virus and is given in the form of a nasal mist.
"But the mRNA vaccine is very, very different," Pekosz said, explaining that mRNA vaccines can teach the immune system to fight a virus without ever coming into contact with it.
One limitation of the current flu vaccines is that they take about six months to develop, meaning scientists must choose which strains they think will be prevalent in the next flu season before the current one is over.
An mRNA flu vaccine, on the other hand, can be developed in about a month or so, giving researchers more time to determine which strains to protect against.
All of this means "you can much more accurately match an mRNA flu vaccine to the strains of virus that are circulating," Pekosz said.
Messenger RNA vaccines still present challenges. The Pfizer and Moderna coronavirus vaccines, for example, must be kept at extremely cold temperatures, making transport and storage a challenge. It's also not clear how long this vaccine-induced immunity will last. And although most side effects to the vaccine are not serious, some people have reported several days of things such as fatigue, body aches and nausea.
Still, researchers say mRNA vaccines are a success. And because the mRNA vaccine platform that was used for the coronavirus vaccines is almost exactly the same platform needed for the flu, "everything that has worked so beautifully for covid-19 could theoretically work in exactly the same way for influenza," Pekosz said.
However, researchers say mRNA flu shots are not likely going to be developed and approved in time for the upcoming flu season, and some estimate that it could take several more years to get one on the market.