The issue
Respiratory syncytial virus (RSV) causes serious lung infections in older adults. In a 35‑thousand–person trial, a single 50 µg dose of the mRNA‑1345 vaccine cut RSV lower‑respiratory disease by about 84 % and acute respiratory illness by 68 %, with no new safety concerns.
What do I need to know?
Adults aged 60 and over in 22 countries were randomized 1:1 to the vaccine or placebo. Median follow‑up was 112 days. Nine vaccine recipients versus 55 on placebo developed RSV lower‑respiratory disease with at least two symptoms; three versus 17 developed disease with at least three symptoms.
Local soreness (59 %) and transient fatigue or headache (48 %) were more common with the shot, yet serious adverse events occurred in 2.8 % of both groups, and vaccine‑related serious events were < 0.1 %.
Potential risk of severe RSV infection
Community‑dwelling older adult without chronic lung or heart disease.
Recommended Actions
Review vaccine status at the next appointment; ask if mRNA‑1345 is available this season.
Continue standard infection precautions (hand‑washing, avoiding sick contacts).
Keep flu and Covid boosters up to date.
Imminent risk of severe RSV infection
Age ≥ 75 or age 60–74 with COPD, heart failure, diabetes, or frailty.
Recommended Actions
Prioritize vaccination before local RSV season begins.
Discuss taking acetaminophen or ibuprofen after vaccination if soreness or fatigue occurs.
Monitor for wheezing or shortness of breath during winter months and seek care early.
Confirmed high‑risk situation
Recent hospitalization for RSV, chronic oxygen use, or immunosuppression.
Recommended Actions
Receive mRNA‑1345 promptly (one dose only) unless contraindicated; schedule follow‑up within a month to report any side‑effects.
Ensure pneumococcal and influenza vaccines are current to reduce co‑infections.
Create an action plan with the clinician for rapid antiviral or supportive therapy if RSV symptoms recur.
What can I do?
Ask the doctor, “Am I at potential, imminent, or confirmed RSV risk, and should I get the mRNA vaccine?” Bring a list of medications and any breathing problems you have had. After vaccination, note arm soreness, fever, or fatigue for a couple of days—these are usually mild—and report any unusual bleeding, bruising, or persistent shortness of breath right away. Caregivers can help arrange transportation for the single appointment and remind loved ones to stay hydrated and rest if mild reactions appear.
