The dream comes a little closer to reality

One of the first clinical trials of an experimental flu vaccine that works against most, if not all, flu strains has recently yielded positive results, and a new study of a similar vaccine – this one using mRNA technology – just started recruiting volunteers.

Creating a universal flu vaccine has long been the dream of vaccinologists.

Seasonal flu kills around 400,000 people each year worldwide, most of them old or very young. Annual deaths in the United States over the past decade have ranged from about 12,000 to 52,000, depending on the severity of illness caused by that season’s main strain, except during the COVID-19 pandemic, when the social distancing and other factors have led to a drop in influenza mortality.

Flu vaccine uptake is low, largely because a new injection or nasal spray is needed every year due to the ability of the flu virus to change slightly but much more frequently than most. other viruses.

The production process is cumbersome and slow. Scientists make educated guesses about which flu strains circulating during the summer monsoon season in South Asia are likely to outcompete others in the West the following winter. These three or four strains are then grown in fertilized eggs for use in seasonal flu vaccines.

Scientists’ predictions are not always accurate. Sometimes there is a mismatch between some of the strains in the vaccine and the strains that are circulating in the United States during this flu season.

A universal vaccine against most flu strains would take much of the guesswork out of flu vaccination and may provide longer-lasting protection, so the annual flu shot would be a thing of the past.

Scientists at the National Institute of Allergy and Infectious Diseases (NIAID) Vaccine Research Center (VRC) have designed an experimental non-RNA vaccine, known as H1ssF, to achieve immunity against a wide range of viruses. A phase I clinical trial of 52 volunteers found it to be safe, well tolerated and induced broad antibody responses, according to two research papers published last month Science Translational Medicine by first authors Sarah F. Andrews, Ph.D., staff scientist, and Alicia T. Widge, MD, staff clinician and associate chief for clinical research and development, and their colleagues at VRC.

Messenger RNA wasn’t discovered until the 1960s, and the first vaccine to use it was against Ebola in Africa, a target population so small there was no commercial development in the United States. The first mRNA vaccines to gain FDA approval were the Pfizer and Vaccines Moderna vaccines against COVID-19. They were very efficient and produced in record time, no eggs were needed.

Using this technology for a universal flu vaccine could offer many benefits.

The early-stage clinical trial that has just begun enrolling 50 healthy adults at Duke University School of Medicine in Durham, North Carolina, will test a new vaccine, also developed at NIAID, that is similar to the universal vaccine against influenza described in recently published articles. But this experimental vaccine, made at the Duke Human Vaccine Institute, uses an mRNA platform.

ClinicalTrials.gov describe the H1ssF-3928 mRNA-LNP trial consisting of three sequential groups of 10 participants each who will receive single low, medium or high doses, with pauses between groups to assess safety. A fourth group will receive an “optimal dose” based on data from the first three.

A fifth group will receive the current quadrivalent seasonal influenza vaccine so researchers can compare immunogenicity and safety and, secondarily, efficacy. Participants will be followed for up to a year after vaccination to measure how long the immune response lasts and whether it remains effective over time as the virus continues to undergo small changes, called drifts.

Emmanuel “Chip” Walter, MD

“It’s an exciting time,” said lead researcher Emmanuel “Chip” Walter, chief medical officer of the Duke Human Vaccine Institute and director of the Duke Vaccine and Trials Unit. “As we continue to test other candidate vaccines, we are moving closer to the ultimate goal of modernizing the flu vaccine to provide better, longer-lasting protection against a virus that kills hundreds of thousands of people each year. in the world.

As deadly as the seasonal flu is – not to mention the misery endured by sickly bedridden multitudes – the possibility of an avian flu pandemic caused by a virus to which no human is immune is far more frightening.

“Hope for a universal vaccine,” Walter said in an email response to questions from Managed Health Framework“must include coverage against avian flu strains”.