Wednesday, March 19, 2008 - 4:35 PM

Invasive Streptococcus pneumoniae (IPD) Serotype Project, Children Under Five, Oklahoma

Jolianne P. Stone1, Lauri Smithee1, Kristy Bradley, and McDermott Michael2. (1) Acute Disease Service/Communicable Disease Division, Oklahoma State Department of Health, 1000 NE 10th Street, Room 605, Oklahoma City, OK, USA, (2) Disease and Prevention Services/Public Health Laboratory, Oklahoma State Department of Health, 1000 NE 10th Street, Oklahoma City, OK, USA

Learning Objectives for this Presentation:
By the end of the presentation participants will be able to describe epidemiology of IPD in children under 5 in Oklahoma, understand the distribution due to vaccine preventable serotypes, and determine the number of preventable cases.

Since 2001, 3510 IPD cases were reported to the Oklahoma State Department of Health (OSDH), with children under 5 constituting 340 (9.7%) of those cases. The incidence of IPD nationally declined following introduction of a the pneumococcal conjugate vaccine (PCV7), which prevents infection by 7 pneumococcal serotypes. Because of low PCV7 uptake in Oklahoma, OSDH and the Centers for Disease Control and Prevention developed protocols to evaluate vaccination history and IPD serotypes.

The objective of this study is to determine occurrence of vaccine preventable IPD among children under 5 and the number of preventable IPD cases.

Serotyping was performed by PCR on sterile site isolates beginning in November 2006. PCV7 vaccine histories were determined using the immunization registry, medical records, and physician and parent contact.

Sixty-nine cases of IPD were reported, with 54 isolates (78.2%) submitted for serotyping. Sixty-three percent (34/54) had at least one vaccination prior to disease, and 23 (68%) were age appropriately vaccinated. Forty-one (76%) isolates have been serotyped. Four isolates were PCV7 serotypes. Of these, one was age appropriately vaccinated at 3 months; two received no PCV7 and were potentially preventable; and the vaccination status of the fourth was undetermined. The most common serotype was 19A, representing 27% of the isolates.

Of the vaccine eligible IPD cases in children under 5, almost half (~46%) were age appropriately vaccinated with PCV7. Despite low PCV7 coverage, serotypes of only 4/41 cases were PCV7 serotypes. Serotype 19A is responsible for the largest proportion of IPD in Oklahoma children under 5, which may parallel a documented increase in non-vaccine serotypes in the US.