P3.165: Maternal Respiratory Syncytial Virus Vaccination during Pregnancy

Background: The respiratory syncytial virus (RSV) is the most significant viral pathogen causing bronchiolitis and pneumonia in infants today. In tropical climates, RSV infections can occur throughout the year. The Centers for Disease Control recommend a respiratory syncytial virus (RSV) vaccine for pregnant women to protect their babies from severe RSV disease. Pregnant women should get a single dose of the vaccine during weeks 32 through 36 of pregnancy. These vaccines are administered September through January in most of the United States. Low maternal vaccination rates against RSV not only compromise maternal health but also leave the neonate unprotected against these respiratory illnesses and increase the risk for outbreaks and hospitalizations. This study aims to assess current RSV vaccination practices among women with high-risk pregnancies.

Methods: This is a descriptive, cross-sectional study of non-adolescent Hispanic mothers whose newborns are admitted to the University Pediatric Hospital Neonatal Intensive Care Unit in San Juan, Puerto Rico, from October 1, 2024, to June 30, 2026. We anticipate that 400 mothers will participate. The survey instrument was designed specifically for this study and consisted of six questions.

Results: We interviewed 45 participants with a median age of 28 years (range, 24-41 years). Fifty-five percent were aware of RSV infection. Only 20% of those referred have been oriented by their obstetricians about the virus. In 73% of cases, immunization was not offered during the current pregnancy. Only 15.6% of the participants received RSV immunization during pregnancy. The immunizations were administered between 26 and 37 weeks of gestation, with a mean of 30.7 weeks. Of the women who were offered the vaccine, 58% received it. Those to whom the obstetrician did not offer the vaccine did not receive it elsewhere (p < 0.01).

Conclusion: The preliminary findings indicate that the recommendations for RSV vaccination during pregnancy are not being followed as intended. This study supports the critical role of the obstetrician in promoting immunization. Health disparities, a lack of knowledge among primary care physicians regarding recommendations, public misinformation, vaccination reluctance, and limited access to the vaccine may be barriers to achieving the goal of appropriate maternal immunization during the RSV season.