Vaccination during pregnancy: Today's need in India

Abstract

Immunization during pregnancy is a simple and effective way to protect the mother and child from certain infections. The immunological changes occur during pregnancy which may be responsible for the susceptibility of certain infectious diseases that increases the risk of more serious outcomes. Vaccination of pregnant women can protect to mother against vaccine-preventable infections, and in so doing potentially protect the fetus. Immunization during pregnancy can also directly protect the fetus and infant via transferred of antibodies from the mother to the fetus. This is why vaccinations during pregnancy are so important. Vaccination during pregnancy is a cost-effective strategy to improve pregnancy outcomes in India. Globally, no scientific study exist which shows the risk of fetus after vaccination of pregnant women with inactivated vaccines or bacterial vaccines or toxoids. Even live vaccines causing risk to fetus is theoretical. Vaccination with inactivated virus, bacterial or toxoid in pregnancy is risk to a developing fetus during pregnancy is theoretical. But definitely the live vaccine poses a theoretical risk to a developing fetus. Therefore, all live vaccines should be avoided during pregnancy. The developing country like India where the people can't afford these vaccines, the government should be included these vaccines in routine immunization program.

Keywords:

• Fetus
• immunity
• infectious diseases
• pregnancy
• vaccines

Maternal immunization provides important health benefits to both pregnant women and to their fetus. Vaccine-preventable diseases cause significant morbidity and mortality among maternal, neonatal, and young infant. Some infections are so serious even they can waste pregnancy, harm her baby during pregnancy or after delivery. These complications can be protected with vaccination. This is why vaccinations are so important for pregnant mothers. Vaccines strengthen the immune systems of body that can fight off serious infectious diseases. A vaccine can help in protection of the mother's body from infections and this immunity passes to her baby during pregnancy. This immunity keeps the child safe during the first few months of life until baby gets his own vaccination. Vaccination also protects mothers from getting a serious disease that could affect future pregnancies. Fetus getting any risk after vaccination of the mother during pregnancy primarily is theoretical. Globally, no scientific study exist which shows the risk of fetus after vaccination of pregnant women with inactivated vaccines or bacterial vaccines or toxoids. Even live vaccines causing risk to fetus is theoretical. Benefits of vaccinating pregnant women usually outweigh potential risks when the likelihood of disease exposure is high, when infection would pose a risk to the mother or fetus, and when the vaccine is unlikely to cause harm. Not all vaccinations are safe during pregnancy but some of inactivated vaccines are considered safe which can be give to pregnant women who might be at risk of infection.

Tetanus vaccine

Tetanus can cause severe morbidity in the mother and mortality in the neonate. Tetanus is a life-threatening bacterial disease that is caused by the toxin of a bacterium called Clostridium tetani which is often found in soil. Tetanus bacteria enter the body through an open wound. It could well be a tiny prick or scratch on the skin, although Tetanus infection is more common when there is a deep puncture wound such as a bite, cut, burn or an ulcer.¹ Tetanus affects a person's nervous system and can be fatal if left untreated. Neonatal tetanus usually occurs in newborns through infection of the unhealed umbilical stump, especially when the stump is cut with a non-sterile instrument. Tetaus is prevented only through vaccination.^2,3 The tetanus vaccine contains noninfectious toxoids. Tetanus toxoids appear safe during pregnancy and are administered in many countries of the world to prevent neonatal tetanus. The World Health Organization (WHO) reported that neonatal tetanus kills over 200,000 newborns each year; almost all these deaths occur in developing countries while it is very rare in developed nations.⁴

To maximize the maternal antibody response and passive antibody transfer to the infant, the national immunization schedule in India recommends the 2 doses of tetanus toxoid (TT) for unknown immunization status of pregnant women i.e the first dose of tetanus toxoid should be administered as soon as pregnancy is detected, second dose of tetanus toxoid is administered after 4 weeks and if a mother received 2 TT doses in the last pregnancy and mother gets again pregnant with in 3 y than only one dose of TT is recommended and that dose is called booster dose. Some experts recommend that the second dose of the vaccine should be given 4 weeks prior to the expected date of delivery. The WHO also recommends that a third vaccine be given 6 months after the second one to provide protection for at least 5 y After TT vaccination, the antibodies formed in mother are transferred to baby and protect baby for a few months after birth. TT vaccination also helps to prevent premature birth or delivery.⁵ The American Congress of Obstetricians and Gynecologists recommends use of tetanus immune globulin, as there is no evidence of any adverse effects to the fetus from the tetanus immunoglobin.⁶

Hepatitis B vaccine

Hepatitis B infection is a serious infection that causes inflammation of the liver. Hepatitis B infection in a pregnant woman might result in severe morbidity for the mother and may increase the chance of preterm birth; however, there is no study which shows that hepatitis B infection is not associated with increased abortion rates, stillbirth, or congenital malformation in fetus.⁷ Therefore, the biggest concern is the vertical transmission i.e transmission of infection from mother to child and as 70% to 90% of babies will remain chronically infected with hepatitis B into adult life and later on can develop liver cirrhosis and hepatocellular carcinoma.⁸

Because of such high risks and the safety and efficacy (seroconversion 90 to 100%) of Hepatitis B vaccine in preventing Hepatitis B infection, it is recommended that Hepatitis B vaccine be given to pregnant women at high risk. The Hepatitis B vaccine is an inactivated (recombinant) virus vaccine; and because the vaccine is composed of noninfectious Hepatitis B surface antigen particles, it should theoretically cause no increased risk.⁹ Globally, many studies confirmed that there are no adverse pregnancy outcomes reported after vaccinated with HepB vaccine during pregnancy.^10,11 Pregnancy is therefore not considered a contraindication to vaccination, however the Hepatitis B vaccine should be offered for pregnant women who are at high risk for acquiring Hepatitis B infection during pregnancy.^9,12

A mother found to be HBsAg-positive should be followed carefully to ensure that the infant receives Hepatitis B Immunoglobulin and start the hepatitis B vaccine schedule no later than 12 hours after birth and that the infant completes the recommended HepB vaccine schedule. No known risk exists for the fetus from passive immunization of pregnant women with immune globulin preparations.

Influenza vaccine

Influenza can cause severe illness in pregnant women than non pregnant women. During pregnancy, there is a change in the immune system, heart and lungs which makes pregnant women more prone to severe illness as well as hospitalizations and even death from influenza. Influenza infection during pregnancy also has a greater chance for serious problems for their unborn babies, including premature labor and delivery.

Women in the second and third trimesters of pregnancy are at increased risk for hospitalization from influenza. Therefore, routine inactivated influenza vaccine is recommended for all women who will be pregnant (in any trimester) during influenza season.¹³ The available inactivated influenza vaccines for the control of seasonal influenza are safe and efficacious and have the potential to prevent significant morbidity and mortality in pregnant women.¹⁴

Live attenuated influenza vaccine is available in form of an intranasal spray and that is not recommended for pregnant women. Maternal influenza immunization offers demonstrated disease prevention benefits for women and their newborns and is a critically important component during pregnancy. Pregnant women should be counseled about the benefits of the influenza vaccine for themselves and their unborn baby.¹⁵

Hepatitis A vaccine

Globally, an estimated 1.4 million cases of hepatitis A virus (HAV) infection occurs every year.¹⁶ The Integrated Disease Surveillance Program of the National Center for Disease Control reported 290,000 cases of acute viral hepatitis in 2013. It is acquired via the fecal-oral route by ingestion of contaminated food or water.¹⁷ Hepatitis A vaccines are derived from viruses grown in diploid cell cultures and are formalin inactivated.^18,19 Safety of hepatitis A vaccination during pregnancy has not been determined. Because hepatitis A vaccine is produced from inactivated virus, the risk to the developing fetus is expected to be low. Therefore, theoretic risks of vaccination should be weighed against the risk for hepatitis A infection in pregnant women who may be at risk for exposure. Finally, if a pregnant woman is exposed to hepatitis A infection, the immune globulin is strongly recommended; the immunoglobulin is considered safe and is more than 85 percent effective in preventing acute hepatitis infection during pregnancy.^20,21

Live attenuated virus is a vaccine that could cross the placenta and result in viral infection to the fetus. That why, most of live attenuated vaccines like Measles, Mumps, Rubella, Varicella, Meningococcal, Human Papilloma Virus (HPV) vaccine and Pneumococcal polysaccharide vaccine, Oral Polio Vaccine (OPV), Inactivated Polio Vaccine (IPV), Typhoid vaccine, Cholera vaccine, Plague vaccine, Japanese encephalitis vaccines are strongly contraindicated in pregnant women.

Conclusion

Vaccination during pregnancy is a cost-effective strategy to improve pregnancy outcomes in India. Vaccination with inactivated virus, bacterial or toxoid in pregnancy is risk to a developing fetus during pregnancy is theoretical. But definitely the live vaccine poses a theoretical risk to a developing fetus. Therefore, all live vaccines should be avoided during pregnancy. Common barriers regarding vaccination during pregnancy are lack of awareness regarding benefits and lack of concerns about vaccine safety. The developing country like India where the people can't afford these vaccines, the government should be included these vaccines in routine immunization program.

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.