A phase 2 randomized controlled dose-ranging trial of recombinant pertussis booster vaccines containing genetically inactivated pertussis toxin in women of childbearing age.

Background: A phase 2 randomized-controlled safety and immunogenicity trial evaluating different doses of recombinant acellular pertussis vaccine containing genetically-inactivated pertussis toxin (PT) was conducted in women of childbearing age in Thailand to identify formulations to advance to a trial in pregnant women.

Methods: A total of 250 women were randomized 1:1:1:1:1 to receive one dose of one of three investigational vaccines including low-dose recombinant pertussis-only vaccine containing 1 μg PT and 1 μg FHA (ap1), tetanus, reduced-dose diphtheria (Td) combined to ap1 (Tdap1) or combined to recombinant pertussis containing 2 μg PT and 5 μg FHA (Tdap2), or one dose of licensed recombinant TdaP vaccine containing 5 μg PT and 5 μg FHA (Boostagen®, TdaP5) or licensed Tdap vaccine containing 8 μg of chemically inactivated pertussis toxoid (PT), 8 μg FHA, and 2.5 μg pertactin (PRN) (Boostrix, Tdap8).