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

Historical Context

The dangers of influenza are often underestimated. A typical flu season can result in tens of thousands of deaths and hundreds of thousands of hospitalizations, with numbers varying annually. Pandemic years, however, are more severe. The 1918-1919 flu pandemic resulted in an estimated 50 million to 100 million deaths globally, infecting nearly one-third of the world’s population within two years.

Unlike seasonal flu, the 1918-1919 pandemic primarily affected young adults. In severe cases, it severely damaged the lungs, leading to oxygen deprivation. The resulting bluish-purple skin tone led to it being called the “purple death.” By the end of the pandemic, 675,000 Americans had died, at a time when the U.S. population was one-third of today’s size.

My Work On Flu

After graduating college in 1976, I worked at St. Jude Children’s Research Hospital before entering medical school. I was assigned to the lab of R. G. Webster, a notable virologist who discovered that new influenza strains can develop when an animal strain, often from birds, mixes with a human strain. This “antigenic shift” can trigger a pandemic.

In February, an H1N1 “swine flu” outbreak at Fort Dix, NJ, alarmed federal officials due to its similarity to the 1918 strain. My role was to collect nasal swabs from pigs on nearby farms, return the samples to the lab, and assist in inoculating fertilized chicken eggs to cultivate and analyze any flu strains the pigs carried. Fortunately, the Fort Dix strain was less contagious than feared and eventually dissipated.

Over three decades later, in 2009, another H1N1 flu virus emerged. It spread rapidly, causing a global pandemic within months. Although milder than the 1918-19 strain, it posed a significant health threat, with nearly everyone being susceptible. The pandemic led to widespread illness, hundreds of thousands of hospitalizations, and over 10,000 deaths, mostly affecting children and adults under 60. Due to overwhelmed emergency rooms, my colleagues and I at Emory emergency medicine, with assistance from Microsoft and the U.S. government, developed a free, web-based self-triage tool to help Americans with the flu decide if ER care was needed.

Influenza Vaccines: Safe, Effective And…Mistrusted

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

Two key points emerged:

“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 submitting its application to the FDA, Moderna tested its mRNA vaccine on over 40,000 participants. The results showed that the vaccine is safe and elicits a stronger immune response than traditional vaccines, especially in those over 50. Coincidentally, The Lancet, a well-regarded British journal, recently published a comprehensive review of the billions of COVID-19 vaccine doses administered so far. 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, the FDA’s approval of Moderna’s mRNA vaccine will pave the way for faster production of effective vaccines for future flu pandemics. Once the genetic sequence of a pandemic strain is identified, an mRNA flu vaccine can be designed, produced, and prepared for distribution in as little as eight weeks, significantly faster than traditional methods.

Unfortunately, Mistrust Of Vaccines Is Stronger Than Ever

Disinformation about the benefits and safety of vaccines—particularly mRNA vaccines—is undermining public confidence in this proven, lifesaving technology. Refusal to receive COVID-19 vaccinations has resulted in over 300,000 preventable deaths, according to GlobalEpidemics.org.

While the FDA’s approval is a positive development, it currently applies only to individuals aged 50 and older. This means younger adults and pediatric patients, including those with asthma or other high-risk conditions, will need to wait for further trials before they can access the vaccine.

Hope Going Forward

Despite some limitations, the positive aspects of this decision overshadow the negatives. After the challenges public health has faced over the last 20 months, the field welcomes any positive development.