(CDC) Pertussis Infection in Fully Vaccinated Children in Day-Care Centers, Israel
We tested 46 fully vaccinated children in two day-care centers in Israel who were exposed to a fatal case of pertussis infection. Only two of five children who tested positive for Bordetella pertussis met the World Health Organization’s case definition for pertussis. Vaccinated children may be asymptomatic reservoirs for infection.
The effects of whole-cell pertussis vaccine wane after 5 to 10 years, and infection in a vaccinated person causes nonspecific symptoms (3–7). Vaccinated adolescents and adults may serve as reservoirs for silent infection and become potential transmitters to unprotected infants (3–11). The whole-cell vaccine for pertussis is protective only against clinical disease, not against infection (15–17). Therefore, even young, recently vaccinated children may serve as reservoirs and potential transmitters of infection.