Vaccine Responses in Infants After Acellular Pertussis Vaccination During Pregnancy in Thailand

Vaccine Responses in Infants After Acellular Pertussis Vaccination During Pregnancy in Thailand

Young infants are most vulnerable to severe disease and even death when infected with Bordetella pertussis. The current vaccines and vaccination programs do not guarantee protection of neonates from this disease. Maternal acquired pertussis-specific antibodies show low concentrations with short persistence in newborns creating a susceptibility gap for infection between birth and the first vaccinations. A possible strategy to protect infants from birth is pertussis vaccination during pregnancy, which will increase the amount of passively transferred maternal antibodies.

However, little is known regarding the effect of high titers of maternal antibodies on the infants immune responses to different pertussis vaccines (whole cell versus acellular). Humoral immune responses will be assessed in infants receiving whole cell versus infants receiving acellular pertussis vaccines. Functionality of the antibodies will also be analyzed.

Inclusion Criteria:

• Willing to be immunized with a pertussis containing vaccine during pregnancy
• Intend to be available for follow-up visits and phone call through 19 months postpartum
• Willing to have infant immunized with a pertussis containing vaccine at 2, 4, 6 months and 18 months of age according to EPI (Expanded Programme of Immunization) and receiving (randomized) either acellular pertussis (aP) (study vaccine) or a whole cell pertussis (wP) vaccine. Consent for participation of the child is needed by both married parents or by a single unmarried other.
• At low risk for pregnancy related complications as determined by the investigator and a second trimester ultrasound with no significant abnormalities.

Exclusion Criteria:

Pregnant subjects

• Multiple pregnancies
• Serious obstetrical risk
• Serious underlying medical condition
• Significant mental illness
• History of febrile illness (greater than or equal to 38°C) within the past 72 hours before injection
• Previous severe reaction to any vaccine
• Receipt of tetanus-diphtheria toxoid immunization within the past 1 month Receipt of an pertussis containing vaccine (Tdap) in the last 5 years
• Receipt of a vaccine, blood product (excluding Rhogam) within the 4 weeks prior to injection through 4 weeks following injection and IVIG (Intravenous Immunoglobulins) within 12 weeks period. One month interval should be respected with another vaccine (except influenza) in orde to evaluate Adverse events following one or both vaccines (fever, local symptoms)
• Receipt of an experimental drug during pregnancy
• Anything in the opinion of the investigator that would prevent women from completing the study or put the woman at risk

Infants

• Preterm delivery before 37 weeks of gestation
• Serious underlying medical condition
• Children suffering from primary humoral immune disorders; suffering from primary cellular immune deficiencies and disorders from the complete cascade
• No informed consent from one or both married parents
• Severe reactions to any vaccine
• Anything in the opinion of the investigator that would prevent children from completing the study or put the child at risk