F2 and pertussis: To investigate the potential effect of pre-pregnancy pertussis vaccination status on anti-PT IgG levels at delivery, we compared total anti-PT IgG levels in women vaccinated against pertussis during 5 years before pregnancy to levels of anti-PT IgG in women not vaccinated against pertussis in the past, vaccinated more than 5 years before pregnancy or their vaccination status was not determined (per Supplementary Table 2).