Serotype 19A Acquisition Tied to Vaccine Schedule
Nasopharyngeal acquisition of serotype 19A linked to 2+1-dose PCV-7 schedule
TUESDAY, Sept. 7 (HealthDay News) -- Heptavalent pneumococcal conjugate vaccination (PCV-7) using a 2+1 dosing schedule may result in an increase in serotype 19A nasopharyngeal acquisition, according to a study in the Sept. 8 issue of the Journal of the American Medical Association.
Elske J.M. van Gils, M.D., of the University Medical Center Utrecht in the Netherlands, and colleagues randomized a group of infants to two doses of PCV-7 at 2 and 4 months of age; 2+1 doses of PCV-7 at 2, 4, and 11 months; or no dose of PCV-7. Nine hundred forty-eight children completed the study.
The investigators found that the cumulative proportion of children who tested positive for new nasopharyngeal serotype 19A acquisition from 6 through 24 months of age was significantly higher in those who received the 2+1-dose PCV-7 schedule (16.2 percent) compared to those who did not receive the vaccine (9.2 percent), but not compared to those who received the two doses of PCV-7 (13.2 percent). The researchers identified 28 different sequence types, including six novel types. The proportion of children with 19A acquisition who had used antibiotics in the last six months (18.7 percent) was the same among the three groups. In the vaccine groups, five isolates were penicillin-intermediate susceptible and three others were not susceptible to erythromycin and azithromycin.
"To the best of our knowledge, this is the first study showing an association between a 2+1-dose PCV-7 schedule and nasopharyngeal acquisition of serotype 19A in children in the first two years of life in a randomized controlled study," the authors write.
Three authors disclosed financial ties to GlaxoSmithKline, Wyeth/Pfizer, Baxter, and/or Novartis.