The new pneumococcal vaccine (PCV13), also known by the brand name Prevnar 13 (Wyeth), was licensed by the US Food and Drug Administration in February 2010 for prevention of invasive pneumococcal disease caused by the 13 pneumococcal serotypes covered by the vaccine in children aged 6 weeks to 71 months.
One of the pivotal studies of the immunogenicity and safety of PCV13 in infants and toddlers appears in the September issue of Pediatrics, released August 23.
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) covered pneumococcal serotypes that caused up to 90% of cases of invasive disease in US before the vaccine was introduced.
“The widespread use of PCV7 in the US has dramatically reduced the burden of this disease in children, with herd immunity benefiting adults as well,” she commented via email. “However, pneumococcal disease still occurs in the US due to replacement serotypes.”
The six additional serotypes included in PCV13 account for up to 92% of cases of invasive disease worldwide in children under 5. “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 pointed out.
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).”
They found that PCV13-elicited IgG titers for the 7 common serotypes were noninferior but somewhat lower than those elicited by PCV7. “The PCV13 toddler dose resulted in higher immune responses compared with infant-series doses,” Dr. Yeh and colleagues found.
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.”
Meanwhile, have any concerns arisen in the short time that PCV13 has been in use in the US? “To date, the experience with PCV13 has been similar to Prevnar-7 in terms of side effects/adverse events,” said Dr. Yeh.
Immunogenicity and Safety of 13-Valent Pneumococcal Conjugate Vaccine in Infants and Toddlers