Highlight
– The CDC has withdrawn its universal recommendation for COVID-19 vaccination in pregnancy, raising questions about protection and risk.
– The FDA’s VRBPAC recommends new vaccines target the JN.1 variant, shaping vaccine composition for the 2025–2026 season.
– The change in recommendations reflects evolving evidence, variant epidemiology, and ongoing debate among clinicians.
– Clinical implications remain complex, especially for high-risk groups and those seeking individualized care.
Background
The COVID-19 pandemic has posed significant risks to pregnant individuals, with mounting evidence from early 2020 indicating increased risks of severe maternal morbidity, preterm birth, and adverse neonatal outcomes following SARS-CoV-2 infection. Initial recommendations from the CDC and other professional societies advocated for COVID-19 vaccination during pregnancy, based on data showing both efficacy and safety in reducing infection, hospitalization, and severe disease. However, shifting viral epidemiology and evolving vaccine effectiveness against emerging variants have prompted reconsideration of these recommendations.
Study Overview and Methodological Design
The CDC’s original recommendation was informed by observational cohort studies, registry data, and post-marketing surveillance, rather than randomized controlled trials (RCTs) specifically enrolling pregnant individuals. These studies generally demonstrated that mRNA vaccines (Pfizer-BioNTech and Moderna) were associated with reduced risk of severe COVID-19 and hospitalization in pregnant populations, with no major safety signals identified for mothers or infants (Shimabukuro TT et al., NEJM 2021; Trostle ME et al., AJOG MFM 2021).
Recent changes in recommendations arise as the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted unanimously in May 2024 to direct manufacturers to develop monovalent vaccines targeting the JN.1 variant or its descendants, notably LP.8.1. This decision reflects the dominance of the JN.1 lineage in global circulation and the waning effectiveness of older bivalent vaccines against current strains.
However, the CDC’s updated position, reportedly retracting its universal recommendation for vaccination during pregnancy, does not appear to be based on new large-scale RCTs or robust observational data specific to the JN.1 variant in pregnant populations. Instead, the move likely reflects the evolving risk-benefit calculus based on lower overall COVID-19 transmission, changing variant virulence, and updated vaccine effectiveness estimates.
Key Findings
The key findings underlying this policy shift include:
– Decreased incidence of severe COVID-19 in the general and pregnant populations in 2024 compared to peak pandemic years.
– Waning efficacy of prior vaccines against new Omicron-lineage variants, including JN.1 and its descendants.
– Persistent safety data from US and international registries indicating no significant increase in adverse pregnancy or neonatal outcomes following vaccination (CDC V-Safe Pregnancy Registry; Magnus MC et al., JAMA 2022).
– Lack of new evidence demonstrating significant additional benefit of vaccination for low-risk pregnant individuals in the context of current viral circulation and population immunity.
Statistical interpretation of registry data continues to show relative risk reductions for severe outcomes in vaccinated versus unvaccinated pregnant people, but absolute risk reductions are now modest given lower disease prevalence.
Mechanistic Insights
Pregnancy is characterized by immunological adaptations that increase susceptibility to viral respiratory pathogens, including SARS-CoV-2. COVID-19 infection in pregnancy has been associated with increased risk of severe respiratory compromise, preeclampsia, preterm birth, and, rarely, maternal mortality. Vaccination induces robust maternal antibody responses, with transplacental transfer of IgG providing neonatal protection (Halasa NB et al., NEJM 2022).
The emergence of the JN.1 lineage, with its distinct spike protein mutations, has reduced neutralizing antibody effectiveness generated by older vaccines and prior infection. Early immunogenicity studies suggest that updated monovalent JN.1 vaccines may improve antibody responses, but clinical effectiveness data—especially in pregnant populations—remain limited.
Clinical Implications
The CDC’s change in stance introduces clinical uncertainty:
– For healthy pregnant individuals in areas of low COVID-19 transmission, the absolute benefit of vaccination may be limited.
– For those with comorbidities (e.g., obesity, diabetes, cardiopulmonary disease), or occupational exposure, vaccination may still reduce risk of severe disease.
– Obstetricians and primary care clinicians will need to engage in shared decision-making, emphasizing individualized risk assessment rather than universal recommendations.
– Updated vaccines targeting JN.1 may become available in late 2024; until efficacy and safety data are available in pregnancy, clinicians must weigh the risks and benefits based on the best available evidence.
Limitations and Controversies
– The absence of large RCTs specifically enrolling pregnant people for the JN.1 vaccine limits certainty.
– Heterogeneity in population immunity, viral circulation, and healthcare access may limit generalizability.
– Divergence in guidance between the CDC, FDA, and professional societies (e.g., ACOG, IDSA) may create confusion for clinicians and patients.
– The abruptness of the CDC’s policy update, with limited explanation or published rationale, has resulted in controversy and calls for greater transparency.
Expert Commentary
At a June 6 IDSA briefing, John Lynch, MD, MPH, highlighted the ongoing dilemma faced by clinicians: “A pregnant colleague recently asked me whether she should get a COVID-19 shot. The answer is no longer straightforward. It’s about assessing her individual risk—her health status, community transmission, and personal values.”
The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) have not yet revised their guidance, which as of early June 2024 continues to support offering COVID-19 vaccines to pregnant people after individualized counseling.
Conclusion
The CDC’s withdrawal of a universal COVID-19 vaccination recommendation during pregnancy reflects the dynamic landscape of SARS-CoV-2 epidemiology, vaccine effectiveness, and clinical risk assessment. While updated vaccines targeting JN.1 are forthcoming, clinicians must rely on individualized counseling and shared decision-making. Ongoing surveillance, transparent communication, and future pregnancy-specific vaccine trials are essential to inform optimal care.
References
1. Shimabukuro TT, Kim SY, Myers TR, et al. Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons. N Engl J Med. 2021;384(24):2273-2282. doi:10.1056/NEJMoa2104983 IF: 78.5 Q1 2. Magnus MC, Gjessing HK, Eide HN, et al. Covid-19 Vaccination during Pregnancy and First-Trimester Miscarriage. N Engl J Med. 2022;386(10):951-953. doi:10.1056/NEJMc2114466 IF: 78.5 Q1 3. Halasa NB, Olson SM, Staat MA, et al. Maternal Vaccination and Risk of Hospitalization for Covid-19 among Infants. N Engl J Med. 2022;387(2):109-119. doi:10.1056/NEJMoa2204399 IF: 78.5 Q1 4. Centers for Disease Control and Prevention. V-Safe COVID-19 Vaccine Pregnancy Registry. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/vsafepregnancyregistry.html
5. Infectious Diseases Society of America (IDSA). Press Briefing, June 6, 2024.
