Vaccines and Pregnancy

By Dr. Lisa Hollier, MD MPH

Chief Medical Officer Texas Children’s Health Plan
Professor, Maternal-Fetal Medicine
Director, Health Policy Division, Baylor College of Medicine

Pregnant women, along with their fetuses, are particularly vulnerable to vaccine-preventable disease-related complications. The Centers for Disease Control and Prevention (CDC) have made recommendations for adult vaccines and there are two that are directly recommended for administration during pregnancy, four are recommended in pregnancy based on additional risk factors, and two are specifically recommended during the postpartum period (see table). The American College of Obstetricians and Gynecologists provides an excellent resource for practices with detailed resources including coding information and a variety of forms.

Influenza

Influenza vaccination during pregnancy is effective at preventing influenza in women and the CDC and the American College of Obstetricians and Gynecologists (ACOG) recommends inactivated influenza vaccine (IIV) for all women who will be pregnant during influenza season, including women in the first trimester. In addition to reductions in maternal morbidity and mortality from influenza maternal vaccination confers infant protection from influenza. One large U.S. study showed that maternal influenza vaccination was 91.5% effective at preventing influenza-related hospitalization in infants younger than 6 months.

Despite efforts to increase rates of immunization in practices providing care to pregnant women, the CDC reports that only 50.3% of women who were pregnant during October 2014–January 2015 reported receiving influenza vaccination before or during pregnancy. The other 50% were not simply women who declined. In fact, only 64.9% of women reported receiving a provider offer of influenza vaccination.

Patient concern over safety of vaccines in pregnancy is often cited as a barrier to immunization. Multiple studies demonstrate the safety of influenza vaccination during pregnancy. Several reports of reduced risk of adverse outcomes including reductions in preterm birth, small for gestational age infants, and intrauterine demise associated with influenza vaccination have generated interest in its potential for improving pregnancy outcome.

TDAP

Pertussis can cause severe respiratory disease and mortality in young infants and can progress from mild symptoms to severe respiratory distress very quickly. Because of the infant vaccine schedule for pertussis, infants are unprotected prior to 4 months of age. The greatly increased incidence of pertussis and infant deaths in the United States in 2012 triggered a swift and aggressive recommendation by the CDC’s Advisory Committee on Immunization Practice (ACIP) to revise the recommended schedule for maternal vaccination, stating that all pregnant women, regardless of previous TDAP immunization, should be vaccinated between 27 and 36 weeks’ gestation.

Multiple studies have demonstrated the benefits of repeated vaccination and the safety of this approach to reduce complications among infants. A recent study also demonstrated the safety of simultaneous administration of TDAP and influenza vaccines.

Vaccines for the Future

Vaccines aimed at fetal–infant immunization are in varying stages of research and development for which the target population will be pregnant women. Two examples are group B streptococcus (GBS) and respiratory syncytial virus vaccines. Stayed tuned for additional information as these and others are developed.

References

Centers for Disease Control and Prevention. MMWR. Influenza Vaccination Coverage among Pregnant Women — United States, 2014–15 Influenza Season. 2015;64 (36);1000-1005

Sukumaran L, McCarthy NL, Kharbanda EO, et al. Safety of Tetanus Toxoid, Reduced Diphtheria Toxoid, and Acellular Pertussis and Influenza Vaccinations in Pregnancy. Obstet Gynecol. 2015;126(5):1069-74.