Fact checked on April 15, 2022 by Rich Scherr, a journalist and fact-checker with more than three decades of experience.

Biotechnology company Moderna is expanding its mRNA technology. The makers of the Spikevax COVID-19 vaccine are now working on two more vaccines: one to protect against SARS-CoV-2, influenza, and respiratory syncytial virus (RSV); and another for the four endemic human coronaviruses, which can cause the common cold.

The new vaccines—for which development programs have only just launched—aim to reduce the impact that respiratory viruses have on public health, especially among older adults who are more susceptible to severe illness, according to a news release from the company.

"The U.S. population is aging and it's not hard to predict that common cold viruses will wield an increasingly uncommon burden on our older adults, especially those in caregiving settings," Mark Cameron, PhD, an associate professor in the department of population and quantitative health sciences at Case Western Reserve University School of Medicine who is not involved in the vaccine development, told Health. "Given the safety and efficacy of COVID-19 mRNA vaccines, especially in older adults, it's welcome news that the companies who've made them are developing new programs to tackle other viral respiratory infections."

Two New Vaccines for Common Respiratory Illnesses

Of the two vaccines Moderna is working on, the first is a three-in-one combination respiratory vaccine candidate, known for now as mRNA-1230. It's proposed to be an annual booster used to protect against SARS-CoV-2, influenza, and RSV. Those viruses are the three most significant viruses that cause respiratory disease in older adults. 

Though there are vaccines available now for both COVID-19 and the flu, there's no cure or immunization available to protect against RSV, a virus that hospitalizes nearly 177,000 older adults annually, according to the Centers for Disease Control and Prevention (CDC). About 14,000 people—mainly those older than 65, adults with chronic heart or lung disease, and immunocompromised people—die each year from RSV. 

The second vaccine proposed by Moderna is meant to protect against four endemic human coronaviruses (HCoVs)—specifically HCoV-229E, HCoV-NL63, HCoV-OC43, and HCoV-HKU1—which, combined, account for 10-30% of upper respiratory tract infections worldwide, Moderna said. 

In theory, this vaccine would protect against some, but not all, causes of the common cold. "Endemic coronaviruses account for anywhere from one in 10 to one in three respiratory infections and aren't the only cause of the common cold. There are hundreds of viruses and their variants causing colds," Cameron said. "However by vaccinating against circulating coronavirus, COVID-19, influenza, and RSV, we begin checking off the top viruses capable of causing harm in older adults, especially those with comorbidities."

Benefits of Combination Vaccines

Without research and testing data, it's nearly impossible to know what the benefits or limitations would be for these vaccines. And any specifics regarding either vaccine—what they'll look like, how often people will need to get them, how effective they will be, etc.—will all depend on the outcome of testing during studies and clinical trials.

Regarding RSV, for which there is no vaccine currently, a safe vaccine is not only urgently needed, but necessary, Chandra Shekhar Bakshi, DVM, PhD, associate professor of microbiology and immunology at New York Medical College, told Health. She adds that rolling an RSV vaccine into a triple vaccine, meant to protect against both the flu and COVID-19, would provide greater virus protection for more people. 

Combination vaccines, which protect against multiple diseases through fewer shots, provide benefits for both patients and caregivers, according to the CDC. These vaccines can mean fewer doctor visits, less pain or discomfort, more affordability, and—most importantly—fewer delays in protection against disease. 

However, it's important to remember that no vaccine offers 100% protection against any disease. According to Bakshi, there are certain limitations of mRNA vaccines, like "short duration of immunity resulting in a need for repeated boosters." And while the mRNA vaccines for COVID-19 have been proven as safe and effective, the long-term safety of mRNA vaccines is continually questioned following reports of adverse events, said Bakshi. 

This only adds to the hesitancy around vaccines, and mRNA technology in particular. "I expect some hesitancy [for any mRNA vaccines]," Cameron said. "But if public health agencies and medical professionals can clearly communicate the overwhelming safety of arguably the largest vaccine rollout in history to the general public, I also expect the cumulative safety data of new mRNA vaccines to speak in a similar way."

What Comes Next?

It's important to note that Moderna is very early on in the vaccine development process—the company has simply announced the mRNA vaccine programs, and any vaccines that are developed will need to go through various developmental and clinical trial phases in order for regulatory approval from the U.S. Food and Drug Administration. 

"The company would need to make sure that the candidate vaccines are safe and immunogenic (i.e., they cause an immune response) in animal models and then in small studies of healthy adults," Adam Ratner, MD, director of pediatric infectious diseases at Hassenfeld Children's Hospital at NYU Langone Health, told Health. "If all goes well in those kinds of studies, they would design larger clinical trials to assess safety and efficacy."

If the design, early-stage trials, and larger clinical trials of these vaccines are successful, "it's likely that combination mRNA vaccines will become part of our yearly vaccination program prior to each cold and flu season," Cameron said. "Depending on variables like one's age, it's also possible that mRNA vaccines will replace the need for multiple trips to the pharmacy for vaccines or boosters given their all-in-one design potential." But even then, should clinical trials show success, decisions would have to be made regarding manufacturing, production, scalability, and rollout of the vaccines. 

Even after the vaccines are made commercially available, the FDA doesn't stop monitoring their safety and efficacy: The agency continues to watch the vaccines and any side effects that are reported through surveillance systems like the Vaccine Adverse Event Reporting System (VAERS), the CDC's Vaccine Safety Datalink, and others.

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