Which strain does the PCV13 vaccine protect against?

The PCV13 vaccine, also known as the 13-valent pneumococcal conjugate vaccine, is designed to protect against 13 specific strains of Streptococcus pneumoniae. These strains are implicated in causing severe invasive diseases such as pneumonia, meningitis, and otitis media among others. The vaccine works by stimulating the immune system to recognize and respond to these pneumococcal serotypes, significantly reducing the incidence of diseases caused by them. The selection of these particular strains for inclusion in the vaccination is based on their prevalence and association with disease severity.

Other options refer to a number of strains that the vaccine does not cover. For instance, there are other pneumococcal vaccines available that may cover different numbers of strains, but PCV13 specifically targets 13 strains known to be major contributors to pneumonia and other pneumococcal diseases.