Fig 2.

Serum IgG levels against PT, PRN, FHA, FIM 2/3, DT, and TT in pregnant women with different vaccination histories. Data represent antibody titers in women living in the United States and immunized with Tdap during pregnancy (n = 15), and women living in Malawi who received only tetanus vaccination (not Tdap or Td) during pregnancy (n = 26). Dotted lines represent protective thresholds. *P < 0.05, **P < 0.01, ***P < 0.001 by Kruskal-Wallis H test followed by the Dunn’s pairwise comparison with Sidák adjustment for multiple comparisons. DT, diphtheria toxoid; FHA, filamentous hemagglutinin; FIM, fimbriae; PRN, pertactin; PT, pertussis toxin; TT, tetanus toxin.