💉 Vaccinations Guide During Pregnancy

🤰 Why is vaccination done during pregnancy?

During pregnancy, vaccination (a biological protector that pre-immunises the body against a microbe) protects both the mother and the baby. The vaccine has two main benefits:

• Protects the mother: During pregnancy, the immune system is more vulnerable to some infections; Diseases such as flu and COVID-19 may be more severe in pregnant women.
• Protects the baby: Protective antibodies (defense proteins produced by the body against microbes) formed by the vaccine given to the mother pass to the baby through the placenta (the nourishing organ between the mother and the baby). This is called passive immunity (transfer of the mother's ready-made antibodies to the baby). Since the baby cannot receive his own vaccinations in the first months after birth, these maternal antibodies protect him during the most fragile period of life.

According to UpToDate, the mother's antibodies pass to the baby at low levels in the first half of pregnancy; it reaches 50% of the maternal level at 28–32 weeks, equals the maternal level at 36 weeks, and often exceeds the maternal level at birth. Since maternal antibodies peak approximately 4 weeks after vaccination, the optimal time for vaccines intended to protect the baby (such as whooping cough and RSV) is the beginning of the 3rd trimester — thus ensuring both the highest maternal antibodies and the greatest transfer of antibodies before birth.

✅ Recommended Vaccinations During Pregnancy

💪 Tdap Vaccine (Whooping Cough-Diphtheria-Tetanus)

Tdap (tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine) is one of the most important vaccines routinely recommended during pregnancy. It especially protects the baby against whooping cough (a severe cough disease that can be fatal in babies; medical name is pertussis).

• When: During every pregnancy, ideally early in the 27–36 gestational-week window (around weeks 27–28, to maximize transplacental antibody transfer).
• It is repeated with each pregnancy: It is repeated even if it was performed in a previous pregnancy, even if the person has had whooping cough in the past, or if successive pregnancies are less than 12 months apart.
• Why it's important: More than half of babies who get whooping cough catch it from family members, most often their mothers. Babies under 3 months of age are most affected by whooping cough, and the baby can only start getting his or her own vaccine when he or she is 6 weeks old. Antibodies transmitted through maternal vaccination fill this gap.
• Tetanus protection: If 10 years have passed since the last tetanus vaccination, the Tdap dose during pregnancy also serves as a tetanus-diphtheria booster dose.
• If it could not be done: Tdap, which cannot be done during pregnancy, should be done immediately after birth (postpartum).

Tdap has been shown to be safe during pregnancy by numerous studies; No increase in serious maternal, fetal or pregnancy complications was detected.

🤧 Inactivated Flu (Influenza) Vaccine

All people who are or may be pregnant during the flu season should receive the inactivated flu vaccine, regardless of the week of pregnancy.

• When: In any trimester (first, second, or third trimester). It is ideal to administer the vaccine as soon as it becomes available and before influenza activity begins in the community; however, it is still beneficial to do it when the flu is circulating.
• Why the flu vaccine is different from others: Unlike whooping cough and RSV vaccines, the flu vaccine is given to protect both mother and baby; Therefore, it is applied in season, regardless of the week of pregnancy.
• How to administer: By injection into the muscle (shoulder/deltoid muscle).
• Which type: Any licensed inactivated influenza vaccine (IIV) or recombinant influenza vaccine is suitable.
• Evidence: Influenza vaccine reduces the risk of stillbirth in pregnant women (relative risk 0.73) and provides an approximately 41% reduction in laboratory-confirmed influenza in the baby in the first months.

🦠 COVID-19 Vaccine

Nearly all health authorities (CDC, ACOG, SMFM) recommend the COVID-19 vaccine for people who are or may be pregnant.

• When: During any period of pregnancy; The current (2025-2026) formula is recommended for the autumn-winter respiratory disease season.
• Safety and effectiveness: All available evidence shows that the vaccine is safe and effective in pregnant and breastfeeding people and reduces severe disease even if the disease is recovered.
• Pregnancy outcomes: COVID-19 vaccine reduces severe maternal morbidity, preterm birth, and stillbirth, according to ACOG; It also provides passive immunity to the baby after birth.

🫁 Maternal RSV Vaccine (Abrysvo / RSVpreF)

RSV (Respiratory Syncytial Virus — an important virus that can cause bronchiolitis, inflammation of the small airways, and respiratory arrest in infants) is a leading cause of hospitalization and death in infants. RSV vaccine administered to the mother during pregnancy protects the newborn against RSV in the first months.

• Which vaccine: Inactivated, adjuvant-free recombinant RSV vaccine RSVpreF (Abrysvo) . It is the only RSV vaccine approved for pregnancy (other RSV vaccines, such as Arexvy and mRESVIA, are for older adults, NOT for pregnancy).
• When: 32 0/7 – 36 6/7. A single intramuscular dose (once in a lifetime) between weeks of gestation.
• Seasonality: In the northern hemisphere, vaccination is administered between September and January; Thus, babies are protected during the RSV season, October – March/early April. (The World Health Organization allows application from the 28th week to increase opportunities.)
• In subsequent pregnancies: It is not repeated in subsequent pregnancies due to lack of data. The new baby of a mother who was vaccinated in a previous pregnancy should receive monoclonal antibody (nirsevimab) after birth for RSV protection.
• Evidence: In a meta-analysis of 6 randomized trials involving approximately 18,000 pregnant women, RSV-related hospitalizations in the first 180 days were reduced by half in infants of vaccinated mothers (11 versus 22 per 1000 infants; risk ratio 0.5).

🚫 Vaccines Prohibited During Pregnancy (Live Vaccines)

Live attenuated vaccines (vaccines that contain weakened but still live microbes) are not administered during pregnancy because they carry a theoretical risk of infecting the developing baby. These vaccines should be given before pregnancy or after birth (postpartum).

🩺 Vaccinations That Can Be Given Depending on the Situation/Risk Situation

Some inactivated vaccines are not routine, but can be administered safely during pregnancy if there is an indication (medical necessity) based on the pregnant woman's health condition, profession, travel plan or exposure risk:

• Hepatitis B: It is a recombinant (non-live) vaccine, there is no known harm to the baby. It can be performed at any time during pregnancy to complete the series started before pregnancy or to unvaccinated pregnant women with a high risk of hepatitis B.
• Hepatitis A: It is an inactive vaccine; It can be done in cases such as travel, occupational risk, chronic liver disease.
• Pneumococcal (pneumonia): It can be administered to pregnant women at high risk of invasive pneumococcal disease, according to indication.
• Meningococcal: MenACWY can be performed if the risk is high; For MenB vaccine, the risk-benefit is evaluated individually and, if possible, it is postponed until after pregnancy.
• Hib (Haemophilus influenzae type b): It can be performed if there is an indication in certain chronic diseases (for example, spleen removal).
• Rabies: It is an inactive vaccine; If pre-contact or post-contact protection is required, it is done in the same way during pregnancy as for non-pregnant women.
• Tetanus (Td): Applied if necessary for injury management or if not fully vaccinated.
• Travel vaccines: Vaccines such as inactive typhoid (Typhim Vi), inactive Japanese encephalitis, IPV (inactive polio) are considered if the risk is high during unavoidable travel.

General rule: Inactivated (non-live) vaccines are no more dangerous than the disease they prevent; It can be applied during pregnancy if there is medical necessity. If there is no urgent need, it is a reasonable approach to postpone the vaccination to be given in the first trimester (organ development period) until the 2nd trimester.

👶 Postpartum Items to be Completed

🍼 Breastfeeding and Vaccinations

• Breastfeeding is not a barrier to recommended vaccinations during pregnancy. Inactivated vaccines are administered safely to breastfeeding mothers.
• Live vaccines such as MMR (MMR) and chickenpox can also be safely administered to breastfeeding mothers.
• IgA antibodies formed by the flu vaccine pass into breast milk, providing additional protection to the baby.
• Exceptions: Yellow fever and smallpox vaccines require caution in breastfeeding — these vaccines should be evaluated with a physician if necessary.

❓ Frequently Asked Questions and Safety

Do vaccines cause autism?

No. The vast majority of scientific evidence shows that there is no relationship between vaccines and autism. This applies both to the vaccines themselves and to the preservatives they contain (e.g. thiomersal).

Are the preservatives (thiomersal, adjuvants) in the vaccine harmful?

No. Adjuvants, such as aluminum salts commonly used in pregnancy, have a good safety profile. There is no evidence that vaccines containing thiomersal have adverse effects on the babies of people who receive these vaccines during pregnancy.

Do inactivated vaccines harm the baby?

There is no evidence that approved inactivated (non-live) vaccines harm the pregnant woman or the baby. The main risk group are live vaccines and therefore they are not administered during pregnancy.