Management of RSV in Pregnant Patients
Pregnant patients at 32-36 weeks' gestation should receive RSVpreF vaccine (Abrysvo) as a single dose during September through January to prevent severe RSV disease in their infants during the first 6 months of life. 1
Prevention Strategy: Maternal Vaccination
Timing and Administration
- Administer RSVpreF vaccine between 32 weeks 0 days and 36 weeks 6 days of gestation to minimize potential preterm birth risk while maximizing infant protection 1, 2
- Give the vaccine seasonally during September through January in most of the continental United States, starting 1-2 months before anticipated RSV season onset 2, 3
- The vaccine requires at least 14 days after administration for adequate antibody development and transplacental transfer to protect the infant 3
- RSVpreF can be co-administered with Tdap, influenza, and COVID-19 vaccines at different anatomic sites on the same day 2
Safety Profile and Risk-Benefit
The FDA approved this vaccine despite observing more preterm births in vaccine recipients, though differences were not statistically significant:
- In the approved 32-36 week interval: 4.2% preterm births in vaccine group vs. 3.7% in placebo group 2
- Most preterm births (72%) occurred at 36 weeks' gestation 2
- Hypertensive disorders of pregnancy were observed more frequently in vaccine recipients but were not statistically significant 1, 2
- The FDA determined benefits outweigh risks when administered at 32-36 weeks, given RSV causes 58,000-80,000 annual hospitalizations in children under 5 years 2
Alternative: Infant Monoclonal Antibody
When to Use Nirsevimab Instead
- Either maternal vaccination OR infant nirsevimab is recommended, but both are not needed for most infants 1, 3
- Nirsevimab should be given to infants when:
Management of Active RSV Infection in Pregnant Patients
Clinical Presentation
- RSV has an attack rate of 10-13% among ambulatory pregnant women during respiratory virus season 5
- 50% of PCR-confirmed RSV cases in pregnant women present with lower respiratory tract illness symptoms 5
- Most pregnant women with RSV have mild disease; severe outcomes are uncommon 6
- Pregnancy is not a risk factor for severe RSV outcomes (ICU admission or death) based on surveillance data 6
Diagnostic Approach
- Obtain nasal-pharyngeal swabs for real-time reverse transcription PCR testing when pregnant patients present with acute respiratory illness ≤7 days duration 5
- Consider serology testing (Western Blot, microneutralization assay) as PCR alone may miss cases 5
Treatment Considerations
- Supportive care is the mainstay for pregnant patients with RSV infection 7, 8
- No specific antiviral therapy is routinely recommended for pregnant patients with RSV 7, 8
- Monitor for progression to lower respiratory tract disease requiring hospitalization 5, 6
Critical Contraindications and Precautions
- Contraindicated in persons with history of severe allergic reaction (anaphylaxis) to any vaccine component 3
- Delay vaccination for moderate or severe acute illness with or without fever 3
- Healthcare workers and visitors who are pregnant should avoid exposure to aerosolized ribavirin (used in immunocompromised patients) due to potentially teratogenic effects 1
Implementation Algorithm
At 32 weeks' gestation during RSV season (September-January):
- Offer RSVpreF vaccine unless contraindicated
- Document vaccination date and gestational age
- Counsel that infant will not need nirsevimab if born ≥14 days after vaccination and ≥34 weeks' gestation
If patient declines or misses vaccination window:
- Plan for infant to receive nirsevimab after birth
- Ensure pediatric team is aware of need for nirsevimab
If infant born <34 weeks' gestation:
- Infant should receive nirsevimab regardless of maternal vaccination status 3