The serotype composition of pneumococcus, which causes pneumonia, meningitis, and sepsis, is changing. As a result, adult vaccination strategies are also changing.
As pediatric pneumococcal vaccination has expanded, circulation of some serotypes targeted by the vaccine has decreased in children, while in adults the proportion of serotypes not included in existing vaccines has relatively increased.
According to the medical community on the 13th, the Korean Society of Infectious Diseases revised its "adult pneumococcal vaccination recommendations" in May and advised all adults 65 and older and high-risk groups ages 19–64 to choose one of the following: PCV21 (21-valent protein conjugate vaccine), PCV20, or sequential vaccination with PCV15 and PPSV23.
This recommendation includes past vaccination history as an important criterion.
For those 65 and older who have not received a pneumococcal vaccine or received only PCV7, one dose of either PCV21, PCV20, or PCV15 can be administered. If only PPSV23 was given, one of PCV21, PCV20, or PCV15 can be given one year after the last dose. If PCV13 was given, PCV21 or PCV20 should be administered after at least one year.
The serotypes that pose problems in adults also show a different pattern from those in children.
An analysis of strains isolated from adult invasive pneumococcal disease (IPD) patients at 16 university hospitals in Korea from 2017 to 2019 found that 74.4% of causative serotypes in adults 19 and older were included in PCV21. The major serotypes at the time were type 3 (13.5%), type 34 (8.1%), type 10A (6.7%), type 19A (6.7%), and type 23A (6.5%).
Older adults and people with chronic diseases are particularly vulnerable to pneumococcal infection. Of the 440 reported pneumococcal infections in Korea in 2025, about 77% were among those 50 and older. Chronic heart and lung disease, diabetes, liver disease, and immunosuppression are also cited as factors that increase the risk of pneumococcal disease. Pneumococcus is transmitted via respiratory droplets from sneezing or coughing.
Kim Young-geun, an infectious disease professor at Wonju Severance Christian Hospital, said, "The distribution of serotypes seen in adult pneumococcal disease is continuously changing," and noted, "Rather than simply comparing the number of serotypes included in vaccines, it is important to consider together the serotypes that actually cause disease in Korea, the patient's age, underlying conditions, and prior vaccination history."
Capvaxive, which is PCV21, received approval from the Ministery of Food and Drug Safety in Aug. last year. It is used to prevent invasive disease and pneumonia caused by the serotypes included in the vaccine in adults 18 and older. It covers 21 serotypes and is administered as a single dose.
Cho Jae-yong, executive director of the vaccines division at Korea MSD, said, "It has been one year since the addition of Capvaxive, the 21-valent vaccine targeting serotypes that are significant in adults, to Korea's vaccination options," and added, "We will help clinicians choose vaccination strategies suited to patient characteristics based on domestic epidemiology and clinical evidence."