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Vaccine related IPD occurrence decreased in infants aged 1 to 90 days since PCV7 introduction
Rates of invasive pneumococcal disease have decreased in infants aged 1 to 90 days, who are too young to be immunized themselves since the introduction of the 7-valent pneumococcal conjugate vaccine; however, overall incidence in this age group is unchanged, according to study results published in Pediatrics.
“Although we did not observe an overall decrease in the incidence of [invasive pneumococcal disease] among infants after the introduction of PCV7, [invasive pneumococcal disease] caused by PCV7 serotypes decreased by 74%, revealing indirect protection for this population from immunization of older children,” researchers wrote.
The study included 513 Utah children with invasive pneumococcal disease (IPD) from 1997 to 2000 (pre-vaccine introduction) and from 2001 to 2010 (post-vaccine introduction)
Researchers found that 7% (n=36) of those with IPD were aged 1 to 90 days and the proportion was identical during both study periods. The pre-vaccine IPD rate was five per 100,000 live births and was unchanged at the post-vaccine introduction period.
Although overall incidence was unchanged, there were changes in serotype distribution and clinical syndromes observed in infants with IPD. There was a 74% decrease of IPD caused by PCV7 (Prevnar, Pfizer) serotypes; however, nonvaccine serotype IPD increased by 57%.
Bacteremia without focus was the predominant clinical syndrome in the pre-vaccine period and meningitis was the predominant syndrome in post-vaccine period (56% and 44%, respectively). Serotype 7F was the predominant cause of IPD in young infants in the post vaccine period and was often associated with meningitis.
“Our study provides evidence of important changes in epidemiology of IPD in infants aged 1 to 90 days over a 10-year period after the introduction of PCV7,” researchers wrote. “Serotype 7f is included in the [13-valent pneumococcal conjugate vaccine], introduced in 2010 and immunization of older infants and children with [13-valent pneumococcal vaccine] may provide indirect protection for infants 1 to 90 days.”
Disclosure: See the study for a full list of disclosures.
