Pertussis is also known as Whooping Cough or the 100 day cough. Outbreaks typically occur every 2-5 years. It is the only vaccine-preventable illness with an increasing number of deaths over the past 30 years in US.

The vaccine against Pertussis is given at 2, 4, 6 and 18 months and then again at age 4-6 and 14-16 and then one booster in adulthood. This leaves newborn infants at risk of getting ill with it before they are immunized at 2 months of age. In infants pertussis can cause babies to stop breathing, as well as causing serious infections and death. Pneumonia is the most common cause of death in children < 6 months of age. In Canada between 2005 and 2009, pertussis infected 86/100,000 infants causing 3 deaths a year.

The baby’s mother is the most common source of pertussis infection, followed by other close contacts of the baby. Immunity against pertussis wanes over time, lasting 5-8 years from vaccination and infection. Therefore, the American and UK guidelines for pregnant women are to vaccinate in the third trimester to protect the newborn. The idea behind this is that:

• Pertussis booster (“Tdap”) during pregnancy causes a surge of maternal antibody production & transfer to baby in protective amounts.
• After 34 weeks antibiodies are actively transferred across placenta. Concentrations are often higher in newborns born at term than the mother.
• Timing of vaccination of mother – The best time is 30-32 wks (but 28-34 weeks is acceptable). Placental transfer is best at this time as largest amount of maternal antibodies are made.

Although data on the safety of pertussis vaccination during pregnancy are limited, reports from the CDC, the US Food and Drug Administration, and pharmaceutical pregnancy registries indicate no safety concerns.