New 13-Valent Pneumococcal Vaccine Expands Protection in Young Children

From Reuters Health Information

NEW YORK (Reuters Health) Aug 23 - The 13-valent pneumococcal conjugate vaccine (PCV13) is as effective as the seven-valent vaccine against the original seven pneumococcal serotypes and should provide further protection against the six additional serotypes, a multicenter team reports.

PCV13, also known by the brand name Prevnar 13 (Wyeth), was approved by the US Food and Drug Administration in February 2010 for preventing invasive pneumococcal disease in children aged 6 weeks to 71 months.

One of the pivotal studies of the immunogenicity and safety of PCV13 in infants and toddlers appeared online today in Pediatrics.

Lead author Dr. Sylvia H. Yeh, at the UCLA-Kaiser Vaccine Research Center in Torrance, California, and colleagues explain that the 7-valent pneumococcal conjugate vaccine (PCV7) covers the serotypes that caused up to 90% of invasive disease in the U.S. before its introduction.

"The widespread use of PCV7 in the U.S. has dramatically reduced the burden of this disease in children, with herd immunity benefiting adults as well," she said in an e-mail. "However, pneumococcal disease still occurs in the U.S. due to replacement serotypes."

The six additional serotypes in PCV13 account for up to 92% of invasive cases worldwide in children under five. "Whereas the potential impact of PCV7 was limited in certain countries such as Africa and Asia, PCV13 potentially expands the impact of disease prevention through vaccine use in these countries," Dr. Yeh said.

The current study compared PCV13 with PCV7 in terms of immunogenicity and safety in toddlers and infants. Ultimately, the authors report, "The evaluable immunogenicity populations consisted of 504 infants (PCV13: 252; PCV7: 252) and 462 toddlers (PCV13: 239; PCV7: 223)."

The immunoglobulin G titers elicited by PCV13 for the original seven serotypes were noninferior but somewhat lower than those elicited by PCV7. The PCV13 toddler dose produced higher immune responses than the infant-series doses, according to the authors.

Local and systemic reactions were mild for the most part and much the same in both vaccine groups. "For specific reactions, the only statistical difference was in the incidence of moderate fever after dose 1 (2.8% vs 0.0% for PCV13 and PCV7, respectively; p=0.026)," the report states.

"Data from this study support that PCV13 will be as effective as PCV7 in preventing disease caused by serotypes common to both vaccines," the authors conclude. "In addition, PCV13 should mediate protection against the 6 additional serotypes, all of which are important worldwide causes of severe pneumococcal disease."

Pediatrics. Posted online August 23, 2010. Abstract