PCV-7 vaccination and serotype 19A pneumococcal acquisition

January 01, 0001

PCV-7 vaccination and serotype 19A pneumococcal acquisition

There has been a rapid increase in invasive multi-drug resistant serotype 19A pneumococcal disease in several countries. There are several possible contributing factors, including the use of PCV-7 vaccinations. These Dutch researchers examined the association of PCV-7 vaccination and nasopharyngeal acquisition of serotype 19A pneumococci via a post hoc per-protocol completer's analysis as part of a randomized controlled trial of nasopharyngeal Streptococcus pneumoniae carriage involving 1003 healthy newborns. Enrollees were followed to the age of 24 months at a time prior to the widespread PCV-7 implementation. Infants were randomly assigned to receive 2 doses of PCV-7 at 2 and 4 months; 2 + 1 doses of PCV-7 at 2, 4, and 11 months; or no dosage (unvaccinated control group).

The researchers found: "Nine hundred forty-eight children completed the study. Fifty-four nasopharyngeal serotype 19A carriage isolates from 318 in the 2-dose group, 66 isolates from 327 in the 2 + 1-dose group, and 33 isolates from 303 in the unvaccinated were collected from 6 weeks through 24 months. The cumulative proportion who tested positive for new nasopharyngeal serotype 19A acquisition from 6 through 24 months of age was significantly higher in those having received the 2 + 1-dose PCV-7 schedule (16.2%) vs those who were unvaccinated (9.2%, relative risk [RR

The researchers concluded: "A 2 + 1-dose PCV-7 schedule was associated with an increase in serotype 19A nasopharyngeal acquisition compared with unvaccinated controls."

The practicle implications of these findings are as yet unclear.

For the full abstract, click here.

JAMA 304(10):1099-1106, 8 September 2010
© 2010 to the American Medical Association
Pneumococcal Conjugate Vaccination and Nasopharyngeal Acquisition of Pneumococcal Serotype 19A Strains. Elske J. M. van Gils, Reinier H. Veenhoven, Eelko Hak, et al.

Category: B. Blood/Immune Mechanisms. Keywords: PCV-7, serotype 19A, pneumococcal, vaccination, nasopharyngeal carriage, randomized controlled trial, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 21 September 2010

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