A new study has found that the effectiveness of routine Tdap booster wanes in adolescents.
Kaiser Permanente's Vaccine Study Center found that the vaccine provides moderate protection against whooping cough during the first year after vaccination, but its effectiveness wanes to less than 9 percent after four years among teenagers who have received only a newer form of the whooping cough vaccine (acellular pertussis vaccine) as infants and children.
The study explored Tdap effectiveness among adolescents during outbreaks of whooping cough in Northern California in 2010 and 2014. Despite Tdap coverage of more than 90 percent in adolescents, they had the highest incidence of pertussis of any age group in 2014. Routine vaccination at ages 11 to 12 did not prevent the epidemic.
This study demonstrates that despite high rates of Tdap vaccination, the growing number of adolescents who have received only the newer acellular pertussis vaccines continue to be at higher risk of contracting whooping cough and sustaining epidemics, said lead author Nicola Klein.
Klein added that because Tdap provides reasonable short-term protection, it may contain whooping cough more effectively if it is administered to adolescents in anticipation of a local outbreak rather than on a routine basis at age 11 or 12.
Klein noted that the strategy of routinely vaccinating adolescents to prevent future disease did not prevent the 2014 epidemic, arguably because the protection afforded by a dose of Tdap was too short-lived. While awaiting development of new vaccines that will provide longer-lasting protection against pertussis, we should consider alternate Tdap immunization strategies for adolescents.
These findings are published in Pediatrics.