The effect of 10-valent pneumococcal conjugate vaccine (PCV10) after 4 years of routine childhood vaccination in Brazil was near elimination of PCV10 serotypes in a study of over 500 children, said Felipe P.G. Neves, PhD, of the University of California, Berkeley, and his associates.

The emergence of multidrug-resistant (MDR) serotype 6C isolates, however, is of concern, they said.

Of the 284 children who attended a public clinic and 238 children who went to two private clinics in the greater Rio de Janeiro metropolitan area between Sept. 29 and Dec. 5, 2014, 118 (23%) were pneumococcal carriers. Their median age was 2 years and all were under age 6 years. All 118 isolates were susceptible to levofloxacin, rifampicin, and vancomycin; 26 (22%) isolates were MDR, and 14 of the 18 serotype 6C isolates were MDR.

“Serotype 6C has already been reported as having caused meningitis in the pre-PCV10 era in northeastern Brazil. Additionally, following PCV7 implementation, carriage with serotype 6C emerged worldwide and reflected in an increase in IPD [invasive pneumococcal disease] cases,” Dr. Neves and his associates said. “Considering the apparent consistency of MDR 6C as the most common serotype associated with colonization in Brazil after PCV10 universal use, ongoing surveillance to monitor its increase in invasive diseases in Brazil is warranted.”

Read more in Vaccine (2017 May 15;35[21]:2794-800).