Impact of a maternal immunization program against pertussis in a developing country

Area of Science:

• Public Health
• Epidemiology
• Vaccinology

Background:

• Pertussis (whooping cough) poses a significant threat in developing nations, with Argentina experiencing a surge in cases and deaths in 2011.
• Over half of pertussis-related infant fatalities in Argentina occurred in infants under two months old, a demographic too young for primary immunization.

Purpose of the Study:

• To evaluate the impact of a maternal Tdap immunization program on reducing infant pertussis morbidity and mortality in Argentina.
• To assess the effectiveness of vaccinating pregnant women against pertussis in protecting young infants.

Main Methods:

• A Bayesian structural time-series model was employed to compare Argentinean states with high (>50%) and low (<=50%) Tdap vaccine coverage.
• States with low vaccine coverage served as a control group, with time series data analyzed before and after the Tdap program implementation.

Main Results:

• A 51% relative reduction in pertussis cases was observed in high-coverage states compared to low-coverage areas.
• Infants aged two to six months experienced a 44% reduction in pertussis illness.
• Pertussis-related deaths decreased by 87% from 2011 to 2013 in the high-coverage regions.

Conclusions:

• Maternal Tdap immunization demonstrates an age-dependent protective effect for infants under six months in a developing country.
• The findings support the implementation of maternal immunization programs as a key strategy to control pertussis in vulnerable infant populations.