How long does the RSV vaccine last?

How long does the RSV vaccine last?

Respiratory syncytial virus (RSV) can cause serious lung and airway infections, especially in infants, older adults and people with weakened immune systems. Two new RSV vaccines—GSK’s Arexvy and Pfizer’s Abrysvo—are now approved for older adults (age 60 and up) in the U.S., and Pfizer’s Abrysvo is also approved for pregnant people to protect their newborns. A common question is: how long does the RSV vaccine last? Here’s what the clinical trials and early real-world data tell us.

1. Vaccine protection in older adults
   Clinical trials for both Arexvy and Abrysvo enrolled tens of thousands of adults age 60 and older, then followed them through an RSV season (roughly October through March in the Northern Hemisphere). Key findings:

   • Peak protection occurs in the first 3 to 6 months after vaccination.
   • Vaccine efficacy against medically attended RSV lower respiratory tract disease (LRTD) was around 80–85% in the first 3 months.
   • Efficacy gradually declines after 6 months, dropping to about 60–70% by month 7–12.
   • By the end of one RSV season (9–12 months post-vaccine), protection can fall below 50% in some older adults, especially those with additional health issues.

   What this means in practice:

   • Because of this waning, health authorities recommend vaccinating older adults annually before RSV season.
   • Getting vaccinated in late summer or early fall (e.g., September or October) ensures peak immunity when RSV starts circulating.

2. Duration of infant protection via maternal vaccination
   Pfizer’s maternal RSV vaccine is given between 32 and 36 weeks of pregnancy. It spurs the mother’s immune system to make antibodies that cross the placenta and protect the newborn during the first months of life—when infants are most vulnerable. Trial data show:

   • Newborns of vaccinated mothers had about 50–60% protection against RSV-related hospitalization during the first 3 months.
   • Protection decreases over time but remains measurable through 6 months of age.
   • By 6 to 12 months, maternal antibodies have largely waned, and infants rely on their own immune response (or their own vaccine, if one becomes available).

   Practical takeaway:

   • For pregnant people, timing the vaccine in the early third trimester is key to maximize antibody levels at birth.
   • After about 6 months of life, infants may no longer have strong maternal antibody protection against RSV.

3. Why immunity wanes
   RSV vaccines are based on stabilized versions of the virus’s fusion (F) protein. They generate strong antibody and T-cell responses, but over time:

   • Antibody levels naturally decline—faster in older adults whose immune systems are less robust.
   • RSV changes slightly year to year. While it doesn’t mutate as rapidly as flu, small shifts can reduce how well last season’s vaccine matches circulating strains.
   • No long-term “memory” of RSV reaches the decades-long durability seen with some childhood vaccines (e.g., measles).

4. Real-world data so far
   Early studies from the first RSV vaccine rollout season (2023–24) support trial findings:

   • Protection against hospitalization remained high (70–80%) in the first 6 months post-vaccination in individuals ≥ 60.
   • Rates of severe RSV illness rose modestly in months 7–12 but still trended lower than in unvaccinated peers.
   • No safety concerns emerged over a full year of monitoring, though ongoing surveillance is critical.

5. Who should get the RSV vaccine and when
   Current U.S. recommendations (CDC, ACIP) advise:

   • Adults 60 and older, especially those with chronic heart or lung disease, diabetes or weakened immunity—get one dose each RSV season.
   • Pregnant people between 32 and 36 weeks gestation—to protect babies in their first 6 months.
   • Some adults 18–59 with certain underlying conditions (e.g., organ transplant recipients) may be eligible—check with your doctor.

   Timing tips:

   • Plan your dose about one month before RSV season begins locally.
   • If you missed vaccination last season, getting it now still offers benefit if RSV is circulating.
   • You can safely get your yearly RSV shot alongside flu and COVID-19 vaccines.

6. Managing expectations
   • No vaccine is 100% effective. You may still get mild RSV symptoms after vaccination—but the shot greatly reduces risk of severe illness, hospitalization and death.
   • Think of the RSV vaccine much like the flu shot: annual dosing, with the aim of reducing worst-case outcomes.

7. Beyond antibodies: other immune defenses
   • T cells and other immune cells also play a role in limiting severity.
   • Even as antibody levels drop, vaccinated individuals often clear the virus faster and have milder symptoms.

8. Looking ahead
   • Research is underway on next-generation RSV vaccines that might last longer or cover more viral variants.
   • Monoclonal antibody treatments (e.g., nirsevimab) for infants offer an alternative protection strategy for very young babies.
   • Broader, longer-lasting immunity could emerge in future RSV seasons—but for now, stick with annual adult dosing and maternal immunization during pregnancy.

Free Online Symptom Check If you develop respiratory symptoms—fever, cough, wheezing or difficulty breathing—you might consider a free, online symptom check, using the doctor approved Ubie Symptom Checker. It’s a quick way to gauge whether you need to see a healthcare professional or pursue testing.

When to speak to a doctor
Always seek medical advice if you experience:

• Severe shortness of breath or rapid breathing
• Chest pain or tightness
• High fever (especially in infants or older adults)
• Confusion, lethargy or bluish lips/face

For any life-threatening or serious concerns, please speak to a doctor or call emergency services right away.

Key takeaways on “how long does RSV vaccine last”

• Older adults: peak protection for 3–6 months, gradual decline by 9–12 months—plan annual doses.
• Infants (via maternal shot): strong protection first 3 months, still measurable to 6 months.
• Waning immunity is expected but serious illness prevention remains high in the first RSV season post-vaccination.
• Annual timing, underlying health and age influence how long the vaccine protects you.

Staying up to date with your RSV vaccine each season is the best way to maintain protection against severe illness. If you have any questions about timing or eligibility, talk with your healthcare provider.