一般2岁以上免疫系统就强了，得了也不会太严重。Prevention The best way to protect against PD is through vaccination. Vaccines are generally safe and effective. Two types of vaccines currently available are- a pneumococcal polysaccharide vaccine (PPSV) used for adults and a pneumococcal conjugate vaccine (PCV) used for infants and children under 2 years of age and children under 5 years who have a weakened immune system. 你可以征询医生意见，看你儿子要打PPSV还是PCV。 Pneumococcal vaccines. (Minimum age: 6 weeks for pneumococcal conjugate vaccine [PCV]; 2 years for pneumococcal polysaccharide vaccine [PPSV]) • Administer 1 dose of PCV to all healthy children aged 24 through 59 months who are not completely vaccinated for their age. • For children who have received an age-appropriate series of 7-valent PCV (PCV7), a single supplemental dose of 13-valent PCV (PCV13) is recommended for: ——All children aged 14 through 59 months ——Children aged 60 through 71 months with underlying medical condition (more...)