What are the current recommendations for respiratory syncytial virus (RSV) vaccination and prophylaxis, including dosing, target populations (infants, pregnant persons, adults ≥ 60 years), and contraindications?

RSV Vaccination Recommendations

All adults aged ≥75 years should receive a single lifetime dose of RSV vaccine, and adults aged 60-74 years should receive it if they have chronic medical conditions such as COPD, asthma, heart failure, diabetes, chronic kidney disease, or immunocompromise. 1

Adult Vaccination (≥60 Years)

Age-Based Recommendations

• Universal vaccination is recommended for all adults ≥75 years regardless of health status or comorbidities, due to significantly elevated rates of RSV-associated hospitalization, severe disease, and mortality 1, 2

• Adults aged 60-74 years should receive RSV vaccine if they have any of the following risk factors: 1, 2

  • Chronic obstructive pulmonary disease (COPD) 2, 3
  • Asthma 2, 3
  • Heart failure or coronary artery disease 2, 3
  • Diabetes mellitus 2, 3
  • Chronic kidney disease (especially end-stage renal disease) 2, 3
  • Chronic liver disease 2, 3
  • Chronic neurological or neuromuscular conditions 2, 3
  • Severe obesity (BMI ≥40 kg/m²) 3
  • Moderate or severe immunocompromise 2, 3
  • Residence in nursing home or long-term care facility 2, 3
  • Frailty or dementia 3

• Adults aged 50-59 years with risk factors can only receive RSVPreF3 (Arexvy), as this is the only vaccine currently approved for this age group 2, 3

Available Vaccines

Three FDA-approved RSV vaccines are available, all with comparable safety profiles: 1, 4

• Arexvy (GSK) - protein subunit vaccine 1, 4
• Abrysvo (Pfizer) - protein subunit vaccine 1, 4
• mResvia (Moderna) - mRNA vaccine, approved May 2024 1, 4

ACIP does not express preference for any particular vaccine 4

Dosing and Administration

• Only a single lifetime dose is recommended - adults who have previously received any RSV vaccine should not receive another dose 1, 2, 3

• Optimal timing is September through November (or August-October), before or early in RSV season, to maximize protection during peak transmission months 2, 3

• Can be co-administered with influenza vaccine at different injection sites, though some studies show numerically lower antibody titers when co-administered (clinical significance unknown) 2, 3

• Eligible adults may be vaccinated at any time of year, but vaccination has most benefit when given just before RSV season 3

Duration of Protection

• A single dose provides protection for at least two consecutive RSV seasons 2, 3
• RSVPreF3 (Arexvy) maintains efficacy for at least three seasons with cumulative efficacy of 62.9% 2
• RSVpreF (Abrysvo) demonstrates sustained protection for at least two seasons with cumulative efficacy of 58.8% 2

Safety Considerations

Critical safety signal: Postlicensure surveillance identified a potential increased risk of Guillain-Barré syndrome following protein subunit RSV vaccination (Arexvy and Abrysvo) 3. This led ACIP to conclude that for adults aged 60-74 years without risk factors, benefits did not clearly outweigh potential harms, resulting in risk-based rather than universal recommendations 3

However, the number of RSV-associated hospitalizations, ICU admissions, and deaths preventable per 1 million vaccine doses exceeds the estimated number of potential vaccine-attributable Guillain-Barré syndrome cases, supporting vaccination in high-risk populations 3

Clinical Implementation

• Patient attestation alone is sufficient evidence of risk factors - extensive medical documentation should not be required 2, 3

• Previous RSV infection does not contraindicate vaccination, as reinfections are common due to short-lived immune responses 2, 3

• If vaccine supply is limited, prioritize: 2, 3

  1. Adults aged ≥75 years
  2. Adults with multiple comorbidities
  3. Residents of long-term care facilities

Maternal Vaccination for Infant Protection

Recommendations

Pregnant persons should receive a single dose of RSVpreF (Abrysvo) at 32-36 weeks' gestation during September through January to prevent RSV-associated lower respiratory tract disease in infants aged <6 months 1

• Abrysvo is the only RSV vaccine approved for use during pregnancy 1, 4

• Timing is critical: At least 14 days are required after maternal vaccination for adequate antibody development and transplacental transfer to protect the infant 2

• Seasonal administration is recommended (September-January in most of continental United States) 1

Safety in Pregnancy

FDA labeled a warning for potential risk of preterm birth, as more preterm births (<37 weeks) were observed among vaccine recipients than placebo recipients in clinical trials, though differences were not statistically significant 1. The vaccine is approved for 32-36 weeks' gestation to avoid potential risk of preterm birth at <32 weeks, which is associated with increased morbidity and mortality 1

More hypertensive disorders of pregnancy were also observed among vaccine recipients compared to placebo, though not statistically significant 1, 4. FDA determined that when administered at 32-36 weeks, benefits outweigh risks 1

Duration of Infant Protection

• Protection conferred through maternal vaccination likely wanes after 3 months, similar to influenza and COVID-19 vaccines given during pregnancy 2

• Additional data are needed to determine whether additional seasonal doses during subsequent pregnancies are indicated 2

Infant Prophylaxis (Alternative to Maternal Vaccination)

Either maternal RSVpreF vaccination during pregnancy OR nirsevimab (Beyfortus) administration to the infant is recommended - both are not needed for most infants 1

Nirsevimab Recommendations

• All infants <8 months born during or entering their first RSV season should receive nirsevimab if mother did not receive maternal vaccination or received it <14 days before birth 1, 5

• Children aged 8-19 months at increased risk for severe RSV disease entering their second RSV season should receive nirsevimab 1

• A single dose provides protection through one RSV season 2

Clinical Algorithm for Infant Protection

1. If pregnant person receives RSVpreF at 32-36 weeks during RSV season: Infant protected for first ~3 months of life; consider nirsevimab if infant will be <8 months during RSV season after maternal antibodies wane 2

2. If pregnant person does not receive RSVpreF or receives it <14 days before birth: Infant should receive nirsevimab 1, 5

3. All infants should be protected against RSV through use of one of these products 1

Key Clinical Pitfalls to Avoid

• Do not revaccinate adults who have already received any RSV vaccine - only one lifetime dose is recommended 1, 2, 3

• Do not delay vaccination in adults ≥75 years while waiting for documentation of risk factors - age alone is sufficient indication 3

• Do not administer both maternal vaccine and infant nirsevimab for most infants - one strategy is sufficient 1

• Do not restrict vaccination based on lack of medical documentation - patient attestation of risk factors is sufficient 2, 3

• Do not assume previous RSV infection provides lasting immunity - vaccination is still indicated 2, 3