Clinical trials for ‘entirely new’ mRNA flu vaccines launching soon. Will they work better?

Based on COVID-19 ‘messenger’ RNA or mRNA vaccines, the new flu vaccines could better protect people from multiple types of flu. First up for testing: older people.

Clinical trials for ‘entirely new’ mRNA flu vaccines launching soon. Will they work better?

An entirely new type of flu vaccine could better protect people from influenza, and clinical trials of the vaccines are starting this month.

The new flu vaccines are based on mRNA technology, the same method that was used to create the most common and successful U.S. COVID-19 vaccines, those made by Pfizer and Moderna.

These vaccines use messenger RNA (or mRNA) to “teach” cells to make proteins. These proteins don’t cause illness, but are the same type that we’d get during a COVID-19 or flu infection. The vaccines then train the immune system to prevent actual infections.

The first group of participants in Colorado — 50 people ages 65 to 85 — could start receiving mRNA flu vaccines as early as mid-August. That’s when Dr. Myron Levin, an expert on infectious diseases and vaccines, expects to enroll older adults for the first round of testing at the University of Colorado Anschutz Medical Campus. Patients at the UCHealth Seniors Clinic will be able to volunteer for the study, as will other older adults.

The Colorado site is one of about 25 across the country where Pfizer will be conducting early tests on a new mRNA flu vaccine.

In the coming weeks, Levin also expects to enroll volunteers for another clinical trial realted to mRNA flu vaccines. Moderna has created a new vaccine that aims to provide combined protection against both flu and COVID-19, including the most recent variants of COVID-19.

While it’s too soon to know whether mRNA flu vaccines will work better than traditional flu jabs, Levin is confident that they will be as safe and effective as the COVID-19 vaccines.

“We’ll just need to confirm their safety and efficacy through the clinical trials,” he said.

Clinical trials launching for new mRNA flu vaccines 

• What: Testing for new type of flu vaccines based on mRNA technology (like COVID-19 vaccines).
• When: The Pfizer clinical trial is expected to start in mid-August. The Moderna clinical trial for a combined flu/COVID-19 vaccine will start later this summer or fall.
• Where: University of Colorado Anschutz Medical Campus in Aurora
• Who is eligible to participate: The new mRNA flu vaccines are being tested first on older adults. People ages 65 to 85 who do not have a history of heart disease are eligible for the Pfizer clinical trial.
• How to get more information: People who wish to be screened to participate my call 720-777-4496 or send an email to 

  [email protected]

Innovations in vaccines are the direct result of global efforts to combat the COVID-19 pandemic.

Levin has developed and tested vaccines for a variety of infections over several decades and said the recent progress is stunning.

“The advancements in developing new approaches to fighting disease, developing vaccines and implementing them have been remarkable,” Levin said.

COVID-19 vaccines clearly have saved millions of lives, he said. While more than a million people have died in the U.S. since the pandemic started, Levin said the death toll would have been far greater without the new mRNA vaccines.

“No vaccine is 100% effective at preventing infection,” Levin said. “But, without these new vaccines, many more people would have died. The important thing about COVID-19 and influenza vaccines is that, although they sometimes fail to prevent infection, they largely prevent serious disease and death. This is a major goal for these vaccines.”

We asked Levin to explain more about mRNA vaccines and the groundbreaking clinical trials that are starting this summer.

How has the COVID-19 pandemic given rise to new flu vaccines?

Both Pfizer and Moderna relied on mRNA technology for their COVID-19 vaccines. This vaccine technology has evolved over the years. Initially, for conventional vaccines, manufacturers used a tiny amount of a live virus and injected it into people to encourage their bodies to fight infections. The new mRNA vaccines instead send “messages” (like a product of a gene of the virus)  to cells that teach them to recognize and fight infections. The mRNA technology is now being used to create a raft of new vaccines. This genetic material stays in the outer part of the cell and never reaches the cell DNA, so it cannot change our cells in a permanent manner.

“These vaccines have worked for COVID-19. Now vaccine makers are asking what other problems we have in the world. Could mRNA vaccines help prevent flu, shingles, RSV and even Ebola? The potential for fighting any given pathogen is endless,” said Levin, who is also an infectious disease professor for the University of Colorado School of Medicine on the Anchutz Medical Campus.

Of course, testing is essential to learn when mRNA vaccines will work and when they might not.

“It’s conceivable that they will work for some pathogens and won’t for others,” he said.

I heard that vaccine makers were actually working on mRNA flu shots before the pandemic hit in 2020. Is that true?

Yes. That’s correct. Researchers have been studying how to use mRNA technology to develop vaccines for several years. Back in 2018, Pfizer started figuring out how to deploy messenger RNA specifically to combat influenza. When the novel coronavirus, SARS-CoV-2, was discovered, scientists quickly shifted and created an mRNA vaccine to fight COVID-19. Now researchers are pivoting again and are testing mRNA technology to fight the flu.

Which flu vaccines are you testing in Colorado?

Levin is beginning this month with a Pfizer flu vaccine.

“It’s an entirely new type of flu vaccine,” Levin said.

He expects to start testing Moderna’s combined flu/COVID-19 vaccine in the late summer or early fall.

Why do we need new flu vaccines?

“The influenza vaccine has a bad rap,” Levin said.

That’s because it’s difficult for vaccine makers to predict which strains of flu will be circulating in advance of the flu season, and thus to create perfect flu vaccines.

“The success of the vaccine varies depending on the ‘virus du jour.’ Viruses like the flu and the COVID-19 virus can change a little or a lot. When they change drastically after the vaccine has been prepared, that’s when you get a pandemic strain,” Levin said.

During a good year, flu vaccines might be 60% effective, but in a bad year — when the vaccine doesn’t match the circulating flu strains well — the flu vaccine might only be about 30% effective.

“That means that only 30% of people were prevented from getting infected,” Levin said.

While an efficacy rate of 30% is not ideal, Levin said it’s important for people to know that the current flu vaccines still prevent most people from getting severely ill or needing to be hospitalized. And they prevent many flu deaths. Still, all health experts would love a better solution.

“We certainly need a better flu vaccine,” Levin said.

When will you start testing mRNA influenza vaccines in Colorado?

Levin expects to start administering the first Pfizer flu vaccine in mid-August. The Moderna clinical trials will start later.

How can I volunteer?

People who wish to be screened to participate my call 720-777-4496 or send an email to [email protected]

How many people will get to participate?

During the first phase of the Pfizer trial, Levin will be able to enroll about 50 participants.

Who is eligible to participate in the clinical trials for the mRNA flue vaccines?

The first phase of the Pfizer mRNA flu vaccine clinical trial aims to test the vaccine on people ages 65 to 85 since older adults are at the greatest risk if they get sick with the flu (along with newborns). If the clinical trials for mRNA flu vaccines go well, later phases will test the new vaccines on younger adults and possibly in children.

The study participants will need to be able to come to the Anschutz Medical Campus in Aurora.

“Like all clinical trials, they will get compensated for their time and effort,” Levin said.

Along with qualifying based on their age, study participants need to be healthy and can’t have a history of heart disease.

In rare cases — about 1 out of every 100,000 — young men who received mRNA COVID-19 vaccines experienced heart abnormalities called myocarditis. This was not a problem for older people.

Levin said those who experienced myocarditis recovered.

“But, out of an abundance of caution, we are now looking to avoid potential heart issues in older people to make sure there are not problems.

“We’ll get an EKG on everybody when we screen them. And after the first dose, we’ll do another EKG.”

Why are older people at greater risk if the get the flu?

As we age, our immune systems also age and they don’t work as well at spotting and fighting intruders like the influenza virus or the virus that causes COVID-19.

“When the immune system ages, it’s called immune senescence,” Levin said. “Our bodies don’t respond as well to vaccines or infections. That’s why when we’re 85 or 90, we don’t do as well with pneumonia or other infections,” Levin said.

What will the clinical trials for mRNA flu vaccines aim to show?

“The trial aims to show whether the new vaccine is safe and whether it’s immunogenic, which means, ‘Does the vaccine stimulate antibodies that are likely to be protective against influenza?’”

Researchers will also be studying what the best dose is and whether a single dose is adequate or whether recipients will need two doses.

How do traditional flu vaccines work?

There are many different kinds of conventional flu vaccines. Some are tailored to older people. Other flu vaccines are formulated for babies and children. There are nasal vaccines and traditional shots.

Conventional flu vaccines work by recognizing a protein on the surface of the flu virus and stimulating an immune response. The protein is called hemagglutinin (comparable to the spike protein on the surface of the SARS-CoV-2 virus that causes COVID-19).

“There are conventional vaccines where vaccine makers grow the flu virus in eggs, then they selectively remove and purify the hemagglutinin,” Levin said.

The vaccines then recognized the hemagglutinin and generate antibodies to fight various strains of the flu.

There are also special vaccines for people who are allergic to eggs, where vaccine makers grow the virus in cells in culture, and not in eggs. The flu antigens can also be made in the laboratory by the recombinant technology used for many medicines, such as insulin

And doses can vary. Older people can get larger doses of a flu vaccine so they can get better protection, Levin said. Another approach is to add a chemical, called an “adjuvant” to the vaccine, which can amplify the immune response to the flu antigen.

Learn more about conventional flu vaccines from experts at the U.S. Centers for Disease Control and Prevention (CDC).

How are new mRNA flu vaccines supposed to work?

The messenger RNA or mRNA gets injected into the person’s body. It is packaged in special particles that improves delivery of the vaccine protein into the cell, the cell uses this vaccine mRNA to make influenza hemagglutinin, which then stimulates antibodies that prevent influenza.

How could mRNA flu vaccines work better than traditional vaccines (if clinical trials prove they do indeed work well)?

It’s easier and faster to develop mRNA vaccines than it is to develop traditional flu vaccines. One benefit of mRNA technology is that vaccine makers can produce the vaccines more quickly.

Since flu strains evolve and change every year, the vaccine makers could wait longer to see what strains are spreading before making educated guesses about which strains that year’s flu vaccine should combat. As a result, mRNA flu vaccines might better protect against current flu strains.

“It is also possible that the influenza proteins made in cells will be better at stimulating an immune response. Or, they might not work as well. That’s why we have to do the experiments,” Levin said.

What are the different types of influenza and will new mRNA flu vaccines combat all of them?

There are two types of influenza that affect humans. Both type A and B strains can cause seasonal flu epidemics. Type A strains caused both the deadly 1918 global flu pandemic and the more recent 2019 H1N1 flu pandemic. New mRNA vaccines are designed to combat both Type A and B strains. That’s also true for conventional flu vaccines.

What if I want to participate in the clinical trials, but I also want to get my regular flu shot this fall?

Volunteers who join the Pfizer study should be done participating in the clinical trial by the time they would get their regular flu shot this fall.

“We’re hoping to have all the information we need by the time flu season hits,” Levin said. “It’s very rare to have flu outbreaks before December. Usually the flu hits in January or later. This (clinical trial) is planned so people can get their standard flu vaccine if it’s still recommended after getting the mRNA flu vaccine.”