Pertussis vaccines are effective, but not long lasting. The good news is that infants are less likely to develop pertussis early in life if their mothers get a tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during pregnancy.
Tdap effectiveness for infant if mother vaccinated during pregnancy
Evidence shows that young infants whose mothers got Tdap during pregnancy are less likely to develop pertussis during the first few critical months of life. A CDC evaluation found Tdap vaccination during the third trimester of pregnancy prevents 78% of pertussis cases in infants younger than 2 months of age. These findings are similar to other global studies that suggest that vaccinating the mother during pregnancy is highly effective at protecting infants against pertussis.
Decreasing infant pertussis incidence since maternal Tdap vaccination
A new CDC study adds more evidence that Tdap vaccination during pregnancy helps protect infants from pertussis during their first 2 months of life. This U.S. study shows that newborn rates of pertussis significantly decreased since Tdap was first recommended during pregnancy.
When infants do get pertussis, their infection is less severe if their mother received Tdap during pregnancy. Infants with pertussis whose mothers got Tdap during pregnancy are much less likely to
- Need to be hospitalized
- Receive intensive care
- Be intubated
Since pregnant women pass some protection to their infants through transplacental transfer of maternal antibodies, their infants also have some protection against the severe outcomes that come with this disease. It is critical that infants receive the 5-dose childhood DTaP series on schedule, so they maintain protection throughout childhood.
By vaccinating a woman with Tdap during pregnancy her infant will gain pertussis antibodies during the most vulnerable time — before 2 months of age. There is a theoretical concern that providing this early immunity may interfere with the infant’s immune response to DTaP though, resulting in a weakening of the infant’s immune response to DTaP. However, routine monitoring through surveillance has not identified this as being an issue.
The benefits of vaccinating during pregnancy and protecting a newborn outweigh the potential risk of blunting the infant’s response to DTaP. Since infants are at greatest risk of severe disease and death from pertussis before 3 months of age – when their immune systems are least developed – any protection that can be provided is critical. Infants should receive their DTaP vaccines on schedule, starting at 2 months of age.
See the Pregnancy and Whooping Cough Research page for a list of published articles specific to preventing pertussis in infants, including vaccine effectiveness studies.