The protective role of maternally derived antibodies against Bordetella pertussis in young infants.

In 20 infants with polymerase chain reaction-confirmed pertussis <6 months of age, median cord blood anti-pertussis toxin, anti-filamentous hemagglutinin and anti-pertactin IgG antibody values were lower than in 80 matched controls: 10.5 versus 13.5 anti-pertussis toxin IU/mL, 14.5/18.0 (anti-filamentous hemagglutinin) and 6.0/9.0 (anti-pertactin), respectively. Although differences of median (and mean) antibody values between groups were not significant, they are in line with the concept of infant protection by maternal antibodies and thus support the strategy of pertussis booster immunization in pregnant women.