The Korean Society of Infectious Diseases has regularly updated its adult immunization guidelines, including the coronavirus disease 2019 (COVID-19) vaccination recommendations in 2023 and the 2024–2025 seasonal update. This article provides a comprehensive update as of September 2025, reflecting the latest evidence and international guidance. Focusing on the 2025–2026 season, it reviews vaccines currently authorized in Korea and their effectiveness against predominant JN.1 sublineage variants, including LP.8.1, NB.1.8.1, and XFG. The updated recommendations prioritize vaccination with LP.8.1-adapted vaccines for high-risk groups—adults aged 65 years and older, individuals aged 6 months and older at increased risk for severe disease, and residents of facilities vulnerable to infection—while vaccination remains available for all individuals aged 6 months and older. A single-dose strategy is generally recommended, although older adults and immunocompromised individuals may consider an additional dose at 6-month intervals in consultation with healthcare professionals. These updates aim to refine Korea’s COVID-19 vaccination strategy and sustain protection in high-risk populations, with recommendations remaining subject to revision as new evidence and epidemiological conditions evolve.

The 20-valent pneumococcal conjugate vaccine (PCV20) was approved by the Korean Ministry of Food and Drug Safety in October 2024. Despite the ongoing national immunization programs that include pneumococcal conjugate vaccines for children and 23-valent pneumococcal polysaccharide vaccine (PPSV23) for adults, the burden of invasive pneumococcal disease and pneumococcal community-acquired pneumonia remains high among the elderly and high-risk adults. Serotypes 3 and 19A, both included in 13-valent pneumococcal conjugate vaccine (PCV13), continue to be the most prevalent serotypes, and infections caused by non-PCV13 serotypes have increased. Given the need to broaden serotype coverage and simplify vaccination strategies, the Korean Society of Infectious Diseases recommends either a single dose of PCV20 or sequential vaccination with 15-valent pneumococcal conjugate vaccine followed by PPSV23 for adults aged 65 years and older, and for high-risk adults aged 19–64 years. These recommendations are based on immunogenicity, safety, and cost-effectiveness data from recent clinical trials. Vaccine selection, dosing intervals, and schedules should be determined according to individual underlying medical conditions and previous vaccination history to optimize protection against pneumococcal disease in the adult population.