Quebec specialist says mRNA flu vaccine seems increasingly likely

A flu vaccine that harnesses the messenger RNA technology that ended the COVID-19 pandemic appears increasingly likely, according to a study published in the prestigious New England Journal of Medicine.

The results of a phase III clinical trial demonstrate similar or superior efficacy of this vaccine compared to traditional vaccines. However, the mRNA vaccine caused more side effects—such as fever or pain at the injection site—than conventional vaccines.

“The vaccine has shown good efficacy against the flu, (…) I think it is promising for the future, but there are still several steps before it can be used in practice,” commented Dr. Nicholas Brousseau, a specialist in preventive medicine at the National Institute of Public Health of Quebec.

The study involved nearly 18,500 participants aged 18 to 64, half of whom received the modRNA vaccine and the other half the control vaccine.

The modified mRNA vaccine showed “statistically superior efficacy to the control vaccine” and “greater immune responses” against certain strains of influenza, while being “associated with a greater number of adverse effects,” the authors summarize.

The main advantage of a vaccine like this, explained Dr. Brousseau, would be the speed with which it could be prepared.

Currently, the preparation of flu vaccines begins in February based on recommendations from the World Health Organization which stem from an analysis of the flu season which is drawing to a close in the Southern Hemisphere.

However, the strategy is far from perfect, since the virus could very well mutate between the preparation of the vaccine in February and its administration in the fall, Dr. Brousseau pointed out.

“The flu is always changing, so speed of production can be a significant advantage,” he explained. “If we can produce the vaccine in a few weeks rather than a few months, we could wait a little longer until the last minute to choose the exact strains that go into the vaccine.”

The longer we wait, “the more likely we are to choose strains very similar to what will be circulating in the population in the fall,” added Dr. Brousseau.

The most important thing right now, he continued, and even “the biggest challenge,” is convincing the population to get vaccinated. Several flu vaccines are available, “and regardless of which one, (…) we still have many elderly people who aren’t getting vaccinated at all, or many young people with chronic illnesses like diabetes or heart disease, who are the target groups for vaccination.”

“Ultimately, the biggest gain we can have is if we succeed in reaching more people, regardless of the vaccine,” said Dr. Brousseau.

The results of this study come from a phase III clinical trial, the last hurdle a new treatment must overcome before being submitted for regulatory approval.

It will therefore be several months, or even a few years, before an mRNA flu vaccine is available to the general public. Several factors, such as side effects, will be taken into account before it is given the green light or not.

“This new vaccine is not a revolution,” concluded Dr. Brousseau. “There is still a lot of work to be done to eventually find a vaccine with even higher efficacy, one that gets closer to 100 per cent.”

The study, led by American physician David Fitz-Patrick of the East-West Medical Research Institute in Honolulu, was funded by the pharmaceutical firm Pfizer, which, along with Moderna, is among the world leaders in the field of messenger RNA vaccines.

–This report by La Presse Canadienne was translated by CityNews