In December 2023, pharmaceutical and biotechnology company Moderna announced that results from a Phase 2/3 clinical trial were published in The New England Journal of Medicine. The study explored an mRNA-based vaccine called mRNA-1345 as a potential preventative therapy against respiratory syncytial virus (RSV). This investigational vaccine encodes for a stabilized prefusion F glycoprotein. F glycoprotein is found on RSV’s surface and contributes to infection. mRNA-1345 hopes to neutralize the antibodies.

Within the study, researchers evaluated the safety and efficacy of mRNA-1345 in adults ages 60 or older. Altogether, 35,541 individuals enrolled. Participants were split into two groups: one which received mRNA-1345 and the other who received a placebo. mRNA-1345 efficacy was 83.7% against lower respiratory tract disease associated with RSV infection when patients had 2+ symptoms and 82.4% when patients had 3+ symptoms.

Currently, Moderna is waiting to learn more about its marketing authorization applications and hoping that it soon sees approval within the United States.

About Respiratory Syncytial Virus (RSV)

The Centers for Disease Control and Prevention (CDC) explain that respiratory syncytial virus is:

a common respiratory virus that usually causes mild, cold-like symptoms.

Many people with RSV recover within one-to-two weeks. However, RSV can be serious and life-threatening in some individuals. Older adults, people who are immunocompromised, and infants have a higher risk of developing severe RSV and/or requiring hospitalization.

RSV is highly contagious. It can be spread if you have direct contact with the virus, touch a surface with the virus on it, or through viral droplets spread through coughing and sneezing. However, there are ways to reduce the spread: frequent hand-washing, limiting exposure to germs, and cleaning commonly used surfaces. Additionally, on the medical side, there are preventive antibodies for infants, a vaccine for those who are between 32-36 weeks pregnant, or vaccines for people ages 60 or older. Learn more about RSV prevention here.

Symptoms of respiratory syncytial virus often appear within four to six days following infection. These symptoms may include:

• Decreased appetite
• Low-grade fever
• A dry cough
• Sneezing
• Sore throat
• Congestion OR a runny nose

In cases of severe infection, symptoms may include:

• Fever
• Wheezing when exhaling
• A severe cough
• Rapid and/or shallow breathing
• Pneumonia
• Bronchiolitis (inflammation of the small airway passages into the lungs)
• Cyanosis (bluish skin discoloration)
• Difficulty breathing
• Lethargy
• Irritability
• Feeding difficulties