August 16, 2019
2 min read

PCV13 serotypes cause nearly 25% of invasive pneumococcal disease in kids

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Sheldon Kaplan
Sheldon L. Kaplan

Serotypes included in the 13-valent pneumococcal conjugate vaccine, or PCV13, continued to cause nearly 25% of invasive pneumococcal disease, or IPD, among children in the United States years after the vaccine’s introduction, according to research published in Pediatrics.

PCV13 (Prevnar 13, Pfizer) was first approved for use in the U.S. in 2010. The vaccine protects against 13 serotypes of pneumococcal bacteria. However, there are approximately 90 serotypes of the bacteria that could potentially cause disease.

“PCV13 clearly has decreased the frequency of invasive and even noninvasive pneumococcal disease due to serotypes in PCV13,” Infectious Diseases in Children Editorial Board Member Sheldon L. Kaplan, MD, head of the pediatric infectious diseases section at Baylor College of Medicine, said in an interview. “In our study, as well as others, about 25% of IPD cases were caused by PCV13 serotypes in U.S. children. I don’t think pediatricians need to be concerned about this, but they should be sure that the children in their practices are as current as possible with respect to PCV13 as well as other vaccines.”

Kaplan and colleagues analyzed cases of IPD among children at eight U.S. children’s hospitals who were treated between 2014 and 2017. They counted doses of PCV if patients developed IPD at least 2 weeks after a dose.

Of the 482 isolates identified, PCV13 serotypes caused 23.9% of IPD cases during the study period. Most cases of IPD caused by a PCV13 serotype (91%) were attributed to serotypes 3, 19A and 19F. More than 40% of these children were not fully vaccinated with PCV13, with no doses or only one dose reported.

“Unfortunately, protection against IPD due to serotype 3 is not optimal and this may be difficult to overcome,” Kaplan said.

According to Kaplan and colleagues, the most common non-PCV13 disease-causing serotypes were 35B, 23B, 33F and 22F. They reported that underlying conditions such as malignancy or central nervous system conditions were more common in children with IPD due to non-PCV13 serotypes (54.5%) compared with children infected with PCV13 serotypes (23%; P < .0001).

According to the study, 28 children who received at least two doses of PCV13 had immune evaluations. Of these children, only one had an immunodeficiency.

“Making every effort to fully vaccinate all children as recommended by the AAP, American Academy of Family Physicians and the CDC is crucial,” Kaplan said. “In some cases, such as children undergoing treatment for leukemia or other malignancies, there may not be much that we can do to reduce IPD because the poor immune response to PCV13.” – by Katherine Bortz

Disclosures: Kaplan reports providing unrelated consultant work for Pfizer. Please see the study for all other authors’ relevant financial disclosures.