Invasive pneumococcal infections continue to decline post-PCV13 introduction

October 9, 2014

PHILADELPHIA — Since the implementation of the 13-valent pneumococcal conjugate vaccine, invasive pneumococcal infections continue to decline, according to study findings presented at IDWeek 2014.

Sheldon L. Kaplan, MD, FIDSA, of Baylor College of Medicine and Texas Children’s Hospital in Houston, and colleagues used data from eight US children’s hospitals to estimate trends among invasive pneumococcal infections in 2012 and 2013.

Overall, there were 113 invasive pneumococcal infections in 2012 and 112 in 2013, compared with 128 in 2011. These declines are significantly associated with decreases in serotype 19A isolates (16 cases in 2012; 12 in 2013 vs. 34 in 2011), and serotype 7F (three cases in 2012; two in 2013 vs. 11 in 2011).

Nine children with serotype 19A and four children with serotype 3 isolates received two or more doses of PCV13 (Prevnar 13, Pfizer) prior to infection. In 2013, 3 of 12 children with serotype 19A invasive pneumococcal infection received four doses of PCV13 prior to infection.

Serotype 3 isolates remained consistent with pre-vaccine estimates and increased from five cases in 2011 to six cases in 2012, and 11 cases in 2013. Serotype 1 accounted for 3 isolates; serotype 19F for five isolates and serotype 7 for 0 isolates during the study period. The most common non-PCV13 serotypes were 33F, 22F, 35B and 23B, according to researchers. Nearly 75% of isolates were non-PCV13 serotypes.

The number of cases of pneumococcal bacteremia and pneumonia decreased yearly, according to researchers, and the number of cases of pneumococcal meningitis remained consistent.

From 2011 to 2013, the associated mortality rate for invasive pneumococcal infections was 13 deaths out of 352 cases, compared with five out of 626 from 2007 to 2009.

“After the introduction of PCV13, the number of invasive pneumococcal infections that we saw per year among eight children’s hospitals decreased in 2011 and 2012, and remained steady in 2013. Compared to the average number of cases in 2007 to 2009, the number of cases in 2011 and 2012 decreased by almost 50%. By 2013, non-PCV13 serotypes accounted for over 70% of isolates caused invasive pneumococcal disease cases in hospitals. Of the PCV13 serotypes, 19A and serotype 3 remain the most common,” Kaplan said during a press conference. – by Amanda Oldt

For more information:

Kaplan SL. Abstract 77. Presented at: IDWeek 2014; Oct. 8-12; Philadelphia.

Disclosure: Some of the researchers report financial ties with Pfizer, UpToDate and Wyeth.