An investigation of Japanese neonatal and maternal antibody status against pertussis

In order to clarify the pertussis immune status of the Japanese population, we investigated serum pertussis toxin (PT)-specific IgG antibody of infants and mothers between April 2016 and March 2018. A total of 206 infants (n = 22, /=37 wGA) and 170 mothers were enrolled. Maternal seroprevalence and antibody geometric mean titer (GMT) were 52.4% and 10.7 EU/mL, respectively. Antibody GMT, seroprevalence, and mean ratio of infant to maternal antibody titers of infants at /=37 wGA (12.1 EU/mL, 57.9%, and 112.6%). Of the 21 infants who underwent a second examination, five infants were positive in the first examination. Of those five, the GMT for PT had decreased by 52.6% on average at 4.3-week intervals. In the second examination, two infants were seropositive. Anti-PT antibody was negative in approximately half of the mothers and infants. Thus, new vaccination strategies such as the vaccination of pregnant women are needed to prevent pertussis infection in early infancy.