Market scope note: This article draws on sources from both Korea and the United States. Each piece of information is labeled 🇰🇷 Korea or 🇺🇸 U.S. in the text to indicate which country it applies to.
When spring arrives, pollen fills the air. When summer fades, the gap between daytime and nighttime temperatures widens. As autumn deepens, cold winds begin to blow, and winter drives people indoors together. These rhythms are familiar to all of us, but for older adults whose immune function has declined, each seasonal transition can itself be a physical burden. Infectious illness may feel like it strikes without warning, yet in reality every season follows a predictable pattern. Recognizing that pattern in advance — and preparing for it — is the most practical form of protection.
When it comes to seniors' health in winter, influenza naturally comes to mind first. 🇰🇷 Korea According to the 2024-2025 Season National Influenza Annual Report released by the Korea Disease Control and Prevention Agency (KDCA) and the National Health Insurance Service (NHIS), the influenza-like illness rate peaked at 99.8 per 1,000 outpatient visits in week 1 of 2025 — the highest figure recorded since the current surveillance system was established in 2016. During the same season, adults aged 65 and older accounted for 4,528 of the sentinel-surveillance hospitalized patients, representing 52.4% of all hospitalizations. In other words, more than half of all hospitalized patients were older adults. 🇰🇷 Korea Domestic research shows that the influenza case-fatality rate for adults aged 80 and older ranges from 1.9% to 2.9%, a sharp increase compared with younger age groups.
🇺🇸 U.S. According to the CDC, flu vaccines prevented approximately 240,000 hospitalizations during the 2024-2025 season, with the greatest benefit seen among adults aged 65 and older. Beyond influenza, RSV (respiratory syncytial virus) is another winter virus capable of causing pneumonia-like symptoms in older adults. 🇺🇸 U.S. The CDC recommends a single dose of the RSV vaccine for all adults aged 75 and older, as well as for adults aged 50 to 74 who have high-risk underlying conditions. CDC modeling estimates that vaccination could prevent 17% of RSV-related hospitalizations among adults aged 50 and older, and 23% among those aged 75 and older.
While influenza and RSV represent the defining infection risks of winter, pneumococcal disease is a bacterial infection that can be life-threatening for older adults regardless of season. 🇰🇷 Korea From 2014 through 2023, the annual average number of reported pneumococcal infection cases was approximately 380, with an increasing trend over the most recent three years. Of the 432 cases reported last year, 244 — or 56.5% — were adults aged 65 and older. In response, the KDCA has since 2013 provided a single free dose of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) to adults aged 65 and older at contracted medical institutions and public health centers nationwide. 🇺🇸 U.S. Medicare Part B covers the full cost of pneumococcal vaccines with no out-of-pocket expense when the provider accepts assignment.
Another infection that warrants particular attention during seasonal transitions is shingles (herpes zoster). Shingles occurs when the varicella-zoster virus — which lies dormant in nerve ganglia after a childhood chickenpox infection — reactivates during a period of reduced immunity. It can cause severe pain and sensory abnormalities. Post-herpetic neuralgia is a common complication, and its incidence increases with age. 🇺🇸 U.S. If you have Medicare Part D or a Medicare Advantage plan that includes prescription drug coverage, you can receive the shingles vaccine (Shingrix) with no out-of-pocket cost. 🇰🇷 Korea The shingles vaccine is not currently included in the National Immunization Program (NIP), so there is no nationwide free vaccination system; however, some local governments operate programs through public health centers that subsidize part of the cost. We encourage you to contact your local public health center first.
Beyond keeping vaccination schedules organized, everyday hygiene habits also play an important role in preventing seasonal infections. Because influenza, RSV, and pneumococcal disease all spread through respiratory droplets and contact, the basics remain essential: washing hands after returning home, ventilating indoor spaces, and wearing a mask when visiting crowded public facilities. When an older adult lives alone, they may experience symptoms without being able to express them and let them pass unnoticed, so it is important for family members to check in regularly. 🇰🇷 Korea The KDCA recommends that adults aged 65 and older receive the flu vaccine and the COVID-19 vaccine on the same day, each at a different injection site, and this program began on October 15, 2025. Vaccination is available at approximately 23,000 contracted medical institutions and public health centers nationwide.
Sources: KDCA and NHIS, "2024-2025 Season National Influenza Annual Report" (April 2026); KDCA Newsletter, September 2025 issue; KDCA Vaccination Information Service (nip.kdca.go.kr); Republic of Korea Policy Briefing, "Pneumococcal National Immunization Program for Adults Aged 65 and Older"; Wello, "2026 National Immunization Schedule"; CDC, "2025-2026 Respiratory Disease Season Outlook" (January 2026); CDC MMWR, "Respiratory Virus Activity July 2024–June 2025" (February 2026); NCOA, "Which Vaccines Does Medicare Cover for Older Adults?" (July 2026); Medicare.gov, "Pneumococcal Vaccination Coverage."
Note: This article was compiled by AI from the sources cited above. We strive for accuracy, but for decisions about your specific situation, please confirm the latest guidance from a professional or the relevant agency.