In the JournalsPerspective

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

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.

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.

    Perspective
    Henry (Hank) Bernstein

    Henry (Hank) Bernstein

    Seven-valent pneumococcal vaccine and PCV13 have notably reduced the rate of IPD since their licensures in 2000 and 2010, respectively. A network of eight U.S. children’s hospitals stratified and analyzed IPD cases caused by PCV13 vs. non-PCV13 serotype isolates to describe the epidemiology of IPD in children from 2014 to 2017.

    This study highlights the overall continued success of pneumococcal vaccines, with three-quarters of IPD cases due to serotypes not covered by the vaccine. Most of these cases occurred in children with underlying conditions, particularly leukemia and other malignancies, as well as in children with hemoglobinopathies or asplenia.

    On the other hand, PCV13 serotypes still accounted for close to one-quarter of IPD cases, most commonly serotypes 3, 19A and 19F. Nearly half of these children had received only one or fewer vaccine doses before their IPD. It appears more cases of IPD could be prevented if children receive their pneumococcal vaccines as recommended. The authors also described the immunologic evaluations of children with IPD caused by PCV13 vaccine serotypes who had received at least two doses of vaccine before infection. Their results call into question the value of an immune evaluation after a case of IPD in an otherwise healthy child without any evidence of immunodeficiency by history, physical exam or lab studies who received at least two doses of PCV13.

    • Henry (Hank) Bernstein, DO, MHCM, FAAP
    • Infectious Diseases in Children Editorial Board member
      Advisory Committee on Immunization Practices member, CDC
      Professor of pediatrics, Zucker School of Medicine at Hofstra/Northwell
      Instructor, Health Care Management
      Harvard T.H. Chan School of Public Health

    Disclosures: Bernstein reports being the editor of Current Opinion in Pediatrics, Office Pediatrics Series.