Vaccine manufacturers responded to the emergence of multiple antibiotic-resistant strains of S. pneumoniae by introducing new pneumococcal vaccines containing additional strains. In March 2009, Synflorix (PCV10), a 10-valent pneumococcal conjugate vaccine, containing three additional strains not included in PCV7 (1, 5, and 7F) received approval for use in Europe. One year later, in February of 2010, Wyeth pharmaceuticals received approval for Prevnar 13 (PCV13) vaccine, a 13-valent pneumococcal conjugate vaccine, which added 6 additional strains (1, 3, 5, 6A, 7F, and 19A) to the original Prevnar (PCV) vaccine.
Recommendations for the use of PCV13 were promptly issued by the CDC to essentially recommend that PCV13 be used in lieu of PCV7. Prior to FDA approval PCV13 was studied for safety in less than 4,800 healthy infants and toddlers and the vaccine was compared to infants and children receiving PCV7, alone or in combination with other vaccines.
The CDC also recommended PCV13 for children and teenagers between 6 and 18 years of age not previously vaccinated and considered to be at high risk for pneumococcal disease related to immunosuppressive conditions including sickle cell anemia, asplenia, HIV, the presence of a cochlear implant, or cerebrospinal fluid leak. At the time of this recommendation in December of 2010, the FDA had not approved the vaccine for use in children over the age of 59 months and did not expand the approval of the PCV13 vaccine for children and teenagers between the ages of 6 and 17 until January of 2013.