The breastmilk of mothers in Bangladesh who received the meningococcal vaccine during pregnancy had anti-meningococcal antibody levels at 3-6 months after delivery of four to five times higher than that of mothers who did not receive the vaccine.
Although this study was published in 2002, the data on this topic are sparse as it is methodologically difficult to conduct studies to evaluate the relationship between anti-meningococcal antibodies in breastmilk and protection.
During the 2009 UK influenza A H1N1 pandemic, pregnant women who contracted influenza were five times more likely to have perinatal mortality (stillbirths) and three times more likely to have a preterm delivery, than were pregnant women who did not contract the virus.
Studies from multiple Western countries have found that pregnant women infected with influenza during the 2009 A/H1N1 pandemic were at higher risk of miscarriages, stillbirths, low birthweight and premature deliveries. The risk of fetal death was between 2 and 5.5 times higher in pregnant women with influenza than in pregnant women without influenza. In the UK, the rate of stillbirths was 4.5 times higher and the likelihood of preterm delivery was 4 times greater in influenza-infected pregnant women than non-infected women.
Although this article indicated that influenza vaccination is safely used for the mother and the fetus, conflicting data exists on the effect of vaccination in improving preterm birth rates.
A study in Australia estimated that adding dTpa vaccination for pregnant women to the current pertussis immunization program for children would prevent an additional 8,800 symptomatic pertussis cases (mostly unreported) and 146 hospitalizations each year in all ages, including infants and their mothers, as well as one death every 22 months. The study found maternal pertussis vaccination to be cost-effective.
Note: The formulation used in this study is abbreviated dTpa.
Despite the introduction of pneumococcal conjugate vaccine (PCV) in the childhood immunization program in New Zealand, the incidence of invasive pneumococcal disease in neonates (<30 days old) remains relatively high at 6 per 100,000 (versus 2/100,000 in the U.S.). Out of 19 cases in infants <30 days old in this study, 9 (47%) occurred during the first 7 days of life and 6 within the first 48 hours. If proven effective, maternal vaccination would cover 74% to 84% of the serotypes that infected these infants, depending on the vaccine.
Pregnant women are at particularly high risk of serious illness and death from a variety of bacterial and viral diseases, such as influenza, pneumococcal pneumonia, and Group B strep, for which vaccines exist or are in development. Vaccine-preventable diseases in pregnancy are associated with adverse pregnancy outcomes such as spontaneous abortion, congenital anomalies, preterm birth, and low birth weight.
Immunization against tetanus, pertussis and influenza during pregnancy has been shown to have a profound effect on the health of the mother and fetus, and increases survival of infants in their first months of life. Maternal immunizations with tetanus toxoid-containing vaccines has been one of the main contributors to the 94% reduction in global deaths due to tetanus since 1988. Between the 1970s to the early 2000s, maternal immunization against pertussis brought disease incidence down to 5,000 cases per year from the earlier 100,000-250,000 cases per year in the United States. Vaccination of mothers for influenza has brought down confirmed cases of the disease by 63%.