Table 2.

Half‐life of tetanus, diphtheria and acellular pertussis (Tdap)‐specific maternal antibody between birth and 7 weeks. Mean half‐life in days and 95% confidence intervals (CI) for maternal IgG against Tdap antigens PTx, FHA, Prn, DTx and TTx

IgG half‐life in infants, in days (CI)
Vaccine Antigen	Unvaccinated	Vaccinated	P‐value
PTx	27·2 (20·0–42·3)	28·9 (26·9–31·3)	0·65
FHA	25·0 (19·5–34·7)	29·7 (27·7–32·1)	0·72
Prn	26·1 (18·5–44·4)	28·1 (25·4–31·3)	0·47
DTx	21·8 (18·2–27·2)	26·1 (24·5–27·9)	0·16
TTx	26·6 (19·3–42·6)	29·5 (26·8–32·8)	0·62

Ig = immunoglobulin; PTx = pertussis toxin; FHA = filamentous haemagglutinin; Prn = pertactin; DTx = diphtheria toxin; TTx = tetanus toxoid.