Tampa Bay Times



The messenger-RNA technology used in the Pfizer and Moderna coronaviru­s vaccines may help scientists develop flu shots in record time.

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 involving years of research, clinical trials and regulatory review and approval.

“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.

But using mRNA for vaccines shifted from experiment­al to critical last year. 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.

“People who were slogging away for many years had money thrown at them to get it done. And they became laser-focused to bring something to market that would have ordinarily taken years,” said Paul Duprex, director of the Center for Vaccine Research at the University of Pittsburgh.

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.

The flu viruses for these vaccines are grown in chicken eggs or in cells inside a petri dish. The viruses are then killed or weakened, and the resulting proteins — the important ingredient in the vaccine — are purified. When the shot is administer­ed, the immune system starts making antibodies against those proteins.

“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. They can also “generate a much stronger immune response than responses that are generated to the protein in a normal flu vaccine,” he added.

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 — even before the current one is over. So by the time the vaccines are ready for distributi­on, a different strain may have emerged as the better target.

An mRNA flu vaccine, on the other hand, can be developed in about a month or so, giving researcher­s plenty 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 as their immune systems gear up to attack the coronaviru­s.

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