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Maternal Immunization

Pfizer is at the forefront of this field, focused on developing maternal vaccines against diseases that pose a significant threat to infants shortly after birth with the goal of helping to give millions of babies around the world a better chance of surviving devastating infectious diseases and living a healthy life.

Four Questions About Vaccination During Pregnancy

  • Are babies more vulnerable to disease in the first few weeks of life?

    Newborns and young infants often cannot mount adequate immune defenses against infections, and direct immunization is typically not an option because young infants have immature, developing immune systems. Consequently, although an infant’s immune system can fight off most infections, some can be fatal.1

  • How does maternal immunization work?

    To compensate for newborns’ still-developing immune systems, nature devised a temporary defense mechanism to help infants fight off infections. Starting in the second trimester, and peaking during the third trimester of pregnancy, antibodies pass from mother to the growing baby through the placenta. These maternal antibodies are highest in the baby at the time of birth and then gradually decline over the next 6 to 12 months as the baby’s own immune system matures. In addition, after birth, antibodies can also be passed from mother to child through breastfeeding.2 Maternal antibodies can help infants to fight off infections during their most vulnerable time of life.2

    In order to provide protection, however, enough antibody needs to be passed to the baby. This means the higher the antibody levels are in the mom, the more likely the mom’s antibodies are transferred to the developing baby and are able to help protect the newborn infant. Pregnant women can acquire high levels of antibodies either through a recent exposure to infectious agents or disease or through vaccination. Maternal vaccination may help ensure that pregnant women have enough antibodies available to transfer to their babies in hopes of decreasing the newborn baby’s risk of disease and death.

  • Is it safe to get vaccines during pregnancy?

    The safety of vaccines during pregnancy is well documented and supported from multiple randomized clinical trials and observational studies that have demonstrated vaccines, like Tdap and Influenza, are safe for use during pregnancy.1,1

    • Currently, the World Health Organization (WHO) recommends three maternal immunization strategies, including for the influenza vaccine, maternal tetanus vaccine and the Tdap vaccine.4
    • The Strategic Advisory Group of Experts (SAGE) of the WHO recommends vaccination against tetanus during pregnancy and identifies pregnant women as a priority group for influenza vaccination.4
    • The WHO Global Advisory Committee on Vaccine Safety has also evaluated data on the safety of immunization of pregnant women for several inactivated and live attenuated vaccines.
    • In the U.S., the Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists (ACOG) recommend that pregnant women in their third trimester get the Tdap vaccine to protect their babies from whooping cough (pertussis) and tetanus.11,12 Both organizations also advise that pregnant women get the flu shot to protect themselves and their babies from flu-related complications.13,14
  • What maternal immunization programs are Pfizer scientists working on?

    To reduce the global disease burden in young infants, the WHO, The U.S. Food and Drug Administration (FDA) and other regulatory agencies, along with The Bill and Melinda Gates Foundation (BMGF), have recognized the importance of developing vaccines specifically for pregnant women.

    Particular focus is now being placed on developing vaccines against respiratory syncytial virus (RSV), a respiratory illness that can be devastating, particularly for infants in the first few months of life, and group B streptococcus (GBS), a bacterial illness that can strike within just a few hours or days after birth.

    Currently, Pfizer’s Vaccine Research and Development (R&D) team is actively and passionately working on developing vaccines for RSV and GBS, with the goal of reducing the global disease burden of these pathogens.

    The successful development and introduction of new maternal vaccines in the coming years have the potential to make a significant, positive, global health impact and to provide additional tools to achieve the important goal of reducing worldwide rate of infant morbidity and mortality.


How Maternal Immunization Helps Protect Babies From Infections

Maternal immunization is a tool to help a pregnant woman pass on disease-specific antibodies to her fetus.

Learn more about maternal immunization


(1) Maternal Vaccination as an Essential Component of Life-Course Immunization and Its Contribution to Preventive Neonatology. US National Library of Medicine National Institutes of Health

(2) Immunization. US National Library of Medicine National Institutes of Health

(3) World Health Organization. Safety of Immunization during Pregnancy: A review of the evidence.

(4) World Health Organization. Immunization coverage.

(5) Centers for Disease Control and Prevention. Why Maternal Vaccines Are Important.

(6) American College of Obstetricians and Gynecologists. Immunization, Infectious Disease, and Public Health Preparedness Expert Work Group.

(7) Pfizer. Press Release.

(8) U.S. Food and Drug Administration. FDA Briefing Document: Vaccines and Related Biological Products Advisory Committee Meeting, May 17, 2018.

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