FDA Approval Of Moderna’s mRNA Flu Vaccine Is Great News. Here’s Why

Historical Context

Influenza is more dangerous than many realize. A “typical flu” season can cause tens of thousands of deaths and hundreds of thousands of hospitalizations, but the counts vary from year to year. Pandemic years are much worse. The 1918-1919 flu pandemic caused between 50 million and 100 million deaths worldwide. Within two years, nearly one-third of the global population was infected.

In contrast to seasonal flu, the 1918-1919 flu pandemic targeted young adults. In severe cases, it ravaged the victim’s lungs, depriving them of oxygen. The bluish-purple tint this produced led people to call it the “purple death.” By the time it ran its course, 675,000 Americans died. The U.S. population in 1918 was one-third its size today.

My Work On Flu

After graduating from college in 1976, I took a summer job at St. Jude Children’s Research Hospital before starting medical school that fall. I was placed in the lab of R. G. Webster, PhD, a renowned virologist who’d determined that new strains of influenza can arise when an existing strain circulating in animals—often birds—mixes with a strain circulating in humans. The resulting “antigenic shift” can spark a pandemic.

That February, an H1N1 “swine flu” outbreak at Fort Dix, NJ, had alarmed federal officials because it resembled the deadly 1918 strain. I was assigned the job of driving to farms in the region to swab pigs’ snouts, bring the samples back to the lab, and help my teammates inoculate fertilized chicken eggs to grow, harvest, and characterize any flu strains the pigs carried. Fortunately, the Fort Dix strain proved to be far less transmissible than initially feared, so it fizzled out.

More than three decades later, in 2009, another H1N1 flu virus emerged. It spread rapidly, becoming a global pandemic in just a few months. Although the illness it produced was much milder than the 1918-19 strain, it posed a serious health threat because nearly everyone was susceptible. Sure enough, the pandemic caused widespread illness, hundreds of thousands of hospitalizations, and more than 10,000 deaths, particularly of children and adults under 60. ERs were so overwhelmed that my Emory emergency medicine colleagues and I developed and deployed, with the help of Microsoft and the U.S. government, a free, web-based self-triage tool to help Americans with the flu determine if they needed ER care.

Influenza Vaccines: Safe, Effective And…Mistrusted

The following year, with associates at RAND Health, I coauthored a commentary on the 2009 pandemic that was published in The New England Journal of Medicine.

Two quotes follow:

“The most obvious lesson is that we currently lack the capacity to develop, produce, and distribute a new vaccine in time to counter a fast-moving pandemic…If sufficient numbers of people can be vaccinated in time, an epidemic can be slowed or even stopped in its tracks”

“The second lesson of the pandemic may be less obvious, but it is just as important as the first. Accelerating vaccine production is necessary but insufficient to counter a future pandemic. For no matter how quickly a safe and effective vaccine is produced, it will do little good if large numbers of people refuse to be vaccinated.”

Yesterday’s FDA decision is relevant to both points.

Moderna’s New mRNA Flu Vaccine Is Safe And Effective

Before it submitted its application to the FDA, the company tested its mRNA vaccine in more than 40,000 people. They found that it is safe and produces a stronger immune response than traditional vaccines, particularly in patients over 50 years of age. Coincidentally, The Lancet, a highly respected British journal, published a comprehensive review last week of the billions of COVID-19 vaccine doses given to date. Based on a massive amount of evidence, the authors concluded that “mRNA vaccines [are] a safe, effective, and adaptable platform with enduring relevance for future infectious disease prevention and public health preparedness, and for the treatment of cancer and autoimmunity.”

Hopefully, FDA’s approval of Moderna’s mRNA vaccine will open the door to much faster production of an effective vaccine to counter any future flu pandemic. Once a pandemic strain’s genetic sequence is identified, an mRNA flu vaccine can be designed, manufactured, and prepared for distribution in as little as 8 weeks – far faster than traditional approaches.

Unfortunately, Mistrust Of Vaccines Is Stronger Than Ever

Disinformation about the benefits and safty of vaccines—particularly mRNA vaccines—is eroding public trust in this time-tested and lifesaving technology. Refusing vaccination against COVID-19 led to more than 300,000 preventable deaths, according to GlobalEpidemics.org.

Although the FDA’s approval is welcome news, it is limited to adults aged 50 and older. That means it will not be available to younger adults or pediatric patients, even those who have asthma or other high-risk conditions. They must wait until further trials are conducted.

Hope Going Forward

That being said, the good in this decision substantially outweighs the bad. Considering the battering public health has taken over the past 20 months, the field needs any win it can get.