Respiratory Syncytial Virus (RSV) is a seasonal virus that spreads during the fall and winter. It is a leading hospitalization among infants.
RSV is a common childhood virus, and almost all children get RSV by the time they are 2 years old. Most cases are mild, cold-like illnesses. Children who do require hospitalization, usually receive supportive therapy and most are discharged in a few days.1
A new vaccine – Abrysvo – has recently received approval from the Centers for Disease Control (CDC), the Food and Drug Administration (FDA), and the American College of Obstetricians and Gynecologists (ACOG).
The vaccine is recommended by ACOG if you are 32 0/7-36 6/7 weeks pregnant from September to January. The vaccine creates antibodies that pass to the baby; this may provide protection from RSV for newborns up to 6 months after birth.2
The RSV vaccine was tested on about 3,500 pregnant women – about 1,500 were 32-36 weeks pregnant. The vaccine trial reduced lower respiratory tract infections (LTRI) of infants by 34-57% and reduced severe LTRI by 76-91% in the first 90-180 days compared to placebo.3
Common side effects reported were injection site pain, headache, muscle aches, and headache.3
The vaccine may not be effective if delivery occurs <14 days after vaccine administration.
The RSV vaccine was associated with a higher incidence of hypertension complicating pregnancy, including preeclampsia and gestational hypertension.4
The vaccine trials had a 5.7% preterm birth rate versus 4.7% in placebo; there was insufficient data to determine whether this was due to the vaccine.4 A previous vaccine (not Abrysvo) for RSV stopped its trial due to an increased risk of preterm birth associated with the vaccine.5
At this time there is insufficient evidence to determine whether the vaccine was the cause of the above pregnancy complications.
The RSV vaccine is currently approved for at-risk older adults – their trial did show an increase in inflammatory neurological events (Guillan Barre Syndrome) of 3 cases among 20,000 individuals in the study, particularly when administered at the same time as another vaccine; this is increased from the general risk (1/100,000).4
There were about 3,600 women included in the primary study. There has not yet been much long-term data about safety. The vaccine was not tested on patients with risk factors in pregnancy such as hypertension, in vitro fertilization, clotting or bleeding disorders, glucose intolerance, thyroid disorders, placental abnormalities, and amniotic fluid abnormalities. It also was not tested on patients with a history of preterm birth or prior stillbirth.6 This limitation makes it difficult to estimate risk/benefit for women who have these complications during their pregnancy.
RSV Monoclonal Antibody
As an alternative to maternal vaccination, an RSV monoclonal antibody has recently been approved by the CDC and FDA that may be given to children to protect against RSV.
The monoclonal antibody – nirsevimab – may provide direct antibodies to the infant and at this time is recommended for infants <8 months who are entering their first RSV season.
A newborn or infant may not be a candidate for nirsevimab if maternal vaccination was received during pregnancy, or if delivery occurs <14 days after vaccination, although an official guideline about this is not yet available.7
Availability and Considerations
The RSV vaccine is not currently available in the Golden Gate OBGYN Clinic. After discussion with your physician, if you decide the vaccine is right for you, we may send the prescription to the pharmacy (if available) and they will either administer the vaccine to you or you may need to coordinate to bring the vaccine back to us and have it administered in the clinic.
The RSV monoclonal antibody may or may not be available in hospitals/clinics/pharmacies.
Further discussion with your pediatrician is recommended to best decide for consideration of the vaccine or monoclonal antibody.
We appreciate your patience as this is a new vaccine with early data and ongoing navigation of implementation within the healthcare system as to how to best and most effectively utilize it.
- https://www.cdc.gov/rsv/high-risk/infants-young-children.html ↩︎
- https://www.acog.org/womens-health/experts-and-stories/ask-acog/should-i-get-the-rsv-vaccine-during-pregnancy ↩︎
- https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2023/09/maternal-respiratory-syncytial-virus-vaccination ↩︎
- thi ↩︎
- https://www.science.org/content/article/fda-advisers-agree-maternal-rsv-vaccine-protects-infants-divided-safety ↩︎
- https://www.pfizermedicalinformation.com/abrysvo ↩︎
- https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2023-09-22/07-Mat-Peds-Jones-508.pdf ↩︎