RSV Vaccine Shows Promise for Mothers with HIV and Their Infants

Maternal vaccination against respiratory syncytial virus (RSV) appears to be both safe and effective for mothers living with HIV and their infants, according to recent findings presented at the Conference on Retroviruses and Opportunistic Infections (CROI) 2026. The study demonstrated robust antibody responses in both mothers and infants, with no identified safety concerns specific to pregnant individuals with HIV.

Understanding RSV and the Need for Vaccination

Respiratory syncytial virus (RSV) is a common respiratory virus that typically causes mild, cold-like symptoms. However, it can be severe, especially in infants and older adults. RSV-associated lower respiratory tract illness (RSV-LRTI) poses a significant risk, and infants exposed to HIV are at an increased risk of severe illness compared to those who are not.

Study Details and Findings

The phase 3, randomized, double-blinded trial, conducted in South Africa, involved 343 pregnant participants living with HIV. Participants received either the RSVpreF vaccine or a placebo between 24 and 36 weeks of gestation. Researchers evaluated the safety and immunogenicity of the vaccine in both mothers and their infants.

Key findings from the study include:

• The vaccine was well-tolerated by pregnant women, with most reactogenicity events being mild to moderate.
• There were no significant differences in adverse events or serious adverse events between the RSVpreF and placebo groups, including rates of hypertensive disorders of pregnancy.
• Infants in the RSVpreF group showed no safety concerns, with similar rates of adverse events, serious adverse events, and preterm birth compared to the placebo group.
• Mothers who received the RSVpreF vaccine developed high levels of neutralizing antibodies against both RSV-A and RSV-B.
• These antibodies were efficiently transferred to infants via the placenta, resulting in significantly higher antibody levels at birth compared to infants born to mothers who received the placebo (geometric mean ratios of 7.8 for RSV-A and 6 for RSV-B).

Expert Perspective

Emily Wasserman, MD, director of clinical development at Pfizer, emphasized that the study “did not identify any contraindications or safety concerns specific to pregnant people living with HIV.” She further stated that the vaccine was safe, well-tolerated, and resulted in the transfer of RSV neutralizing antibodies to infants. Healio

Implications and Future Directions

These findings suggest that maternal RSV vaccination could be a valuable tool in protecting infants, particularly those at higher risk due to HIV exposure, from severe RSV-LRTI. Further research will continue to monitor the long-term effects of this vaccination strategy and its potential impact on infant health outcomes.

Key Takeaways

• Maternal RSV vaccination is safe for pregnant women living with HIV.
• The vaccine elicits robust antibody responses in both mothers and infants.
• Antibodies are efficiently transferred from mother to infant, providing early protection against RSV.
• No safety concerns were identified in infants born to vaccinated mothers.

Source: Safety, Tolerability, and Immunogenicity of RSVpreF Vaccination in Pregnant Participants Living with HIV and Their Infants, PubMed, December 1, 2025.

Additional Information: Study: RSV vaccination benefits moms with HIV and their babies, Healio, February 26, 2026.