The existing vaccine, called Prevnar, protects against the seven main strains of Streptococcus pneumoniae, which not only produce pneumonia but also can invade the blood, middle ear and the covering of the brain and spinal cord.
As the prevalence of the original seven strains of S. pneumoniae was reduced, however, other strains began moving into their niche. Researchers now think that as many as three-quarters of new cases of pneumonia and other streptococcal infections are caused by the six additional strains of bacteria included in the new vaccine, Prevnar 13, along with the original seven.
The safety of Prevnar 13 was evaluated in 5,084 infants and children; the control group was an additional 2,760 who received the original Prevnar. The common adverse reactions were pain, redness and swelling at the injection site, irritability, fever and decreased appetite - all common in those who received the original Prevnar and most other vaccines.
The vaccine is administered in four doses, given at ages 12 to 15 months and 2, 4 and 6 years. The vaccine is available in single-dose, prefilled syringes that do not contain the controversial preservative thimerosal.
Widespread use of the vaccine will require a recommendation by the Centers for Disease Control and Prevention's vaccines advisory committee, which met Wednesday.
The CDC committee recommended using Prevnar 13 to immunize infants and toddlers, as well as in 5-year-olds with underlying medical conditions. It also recommended a supplemental dose for children younger than 5 who have completed the four-dose immunization of the original Prevnar.
In addition, the panel said children who had started their immunization series with Prevnar should complete the series by switching to Prevnar 13 at any point in the schedule.