Pneumococcal conjugate vaccine (called PCV13 or Prevnar 13) is recommended to protect infants and toddlers, and some older children and adults with certain health conditions, from pneumococcal disease. Pneumococcal disease is caused by infection with Streptococcus pneumoniae bacteria. These bacteria can spread from person to person through close contact. Pneumococcal disease can lead to severe health problems, including pneumonia, blood infections, and meningitis.