Updated: Noviembre 14, 2011
Bacterial infections in the coverings of the brain and spinal column (spinal meningitis), lungs (pneumonia), or blood (bacteremia) used to commonly cause serious illnesses with potentially life threatening and damaging consequences in young infants and children. Many of these diseases have become much less common after the Haemophilus influenzae, type b (Hib) conjugate vaccine was introduced in 1987. Streptococcus pneumoniae is a similar but unrelated bacterium to Hib. Unlike with Hib where there was only one type, there are more than 90 types (or serotypes) of Str. pneumoniae.
Serious pneumococcal infections are most common in infants, toddlers, smokers, and the elderly. In addition, people with certain health problems (e.g., immune deficiencies, sickle cell disease, and lack of a functioning spleen) are at high risk for acquiring invasive pneumococcal disease. Children from African-American and Native American populations also have higher rates of invasive (serious) pneumococcal disease than white children.
A heptavalent pneumococcal conjugate vaccine (PCV7 vaccine), containing the 7 most common pneumococcal serotypes causing invasive infections in children in North America was licensed in the US and recommended for routine use in infants in 2000. It has dramatically reduced the rates of invasive pneumococcal disease, otitis media and nasal carriage of the vaccine serotypes among all age groups, including the immunocompromised and older individuals. The vaccine has also reduced the racial disparities in pneumococcal disease. 123
PCV7 has proven to be a cost effective vaccine because of the disease it prevents in young children. Vaccinating children against pneumococcus also provides protection to their family members and the communities where they live, making it a cost saving vaccine when its effects on community immunity are considered.
However, while the PCV7 vaccine has reduced pneumococcal disease caused by the seven most common types causing infection in children, there are other pneumococcal types which can also cause serious infections in children. Surveillance suggests an increase in disease in children aged < 5 years due to these nonvaccine serotypes, especially serotypes 3, 7F, and 19A, some of which are antibiotic resistant.34 Because children are the reservoir for the serotypes that cause invasive disease, broadening the coverage of serotypes in the vaccine is desirable.
On February 24, 2010, the FDA licensed a 13-valent pneumococcal conjugate vaccine (PCV13). On the same day, the Advisory Committee on Immunization Practices recommended that this vaccine replace the PCV7 vaccine in the infant schedule when it becomes available.5 PCV13, will protect against the same seven strains that were in PCV7 but also has the potential to further reduce the amount of invasive pneumococcal disease in the United States caused by 6 additional strains, including 3, 7F and 19A.