Dear Dr. K;
I just turned 65 and I want to get a pneumonia vaccine, but quite honestly, I’m confused by the choices.
The confusion is not unique to you. There has been a longitudinal/temporal change/improvement in the vaccine. To cut to the chase the CDC Advisory Committee on Immunization Practices recommends you (as previously unvaccinated) receive PCV21 followed a year later by PPSV23.
By way of explanation, PPSV stands for pneumococcal polysaccharide vaccine. It is the original vaccine and is similar in formulation to the tetanus vaccine. PCV stands for pneumococcal conjugate vaccine. In this format the polysaccharide antigens are conjugated to a diphtheria protein to elicit a more robust immune response. With the learning curve of time, scientists have found using both formats leads to the best and most durable immune response.
The earliest conjugate vaccine was PCV13 (protecting against 13 of the most common pneumonia types). Over time PCV15, PCV20 and then PCV21 have come along. PCV21 includes 8 serotypes not included in any of the other vaccines. Hence, the CDC’s current advice.