Elderly RSV hospitalizations hit 1.7 times last year's full-year count as Chuseok family gatherings raise transmission fears

Over half of patients develop pneumonia; underlying conditions worsen in up to 80% of cases

One-shot vaccine Arexvy shown to provide protection across three seasons

A family gathering during the holiday season. [Getty Images Bank]
A family gathering during the holiday season. [Getty Images Bank]

Many grandparents are looking forward to holding their grandchildren for the first time in a while this Chuseok holiday — but the joyful reunion comes with a serious warning about a potentially deadly respiratory infection.

The holiday's nature of bringing together infants, young children and the elderly in close contact raises the risk of a rapid spread of respiratory syncytial virus, or RSV.

This year in particular, the number of elderly patients hospitalized with RSV has already far surpassed last year's full-year total — even before the peak season typically begins in October — prompting calls for heightened caution.

Hospitalizations among those 65 and older surge before peak season; Chuseok gatherings raise family transmission risk

According to sentinel surveillance data from the Korea Disease Control and Prevention Agency's infectious disease portal, the number of RSV patients aged 65 and older who were hospitalized stood at 3,247 as of week 34 of this year — 1.7 times the full-year total of 1,906 recorded for the same age group last year. The sharp rise is already under way among older adults, even ahead of the RSV season that typically begins in late autumn.

RSV spreads easily through respiratory droplets from coughing and sneezing. During peak season, a single infected person can pass the virus to roughly three others, making it highly contagious. In enclosed home settings, the secondary transmission rate ranges from 11.6 percent to as high as 39.3 percent. If an infant or toddler carrying the virus has close contact — such as hugging — with grandparents during the holiday, it can lead to a life-threatening infection in the elderly.

Over half develop pneumonia; hospitalization risk up to 13 times higher for those with chronic conditions

RSV is particularly dangerous for older adults because it does not simply cause cold-like symptoms — it can trigger severe, life-threatening complications.

According to domestic research, 56.8 percent of RSV patients aged 65 and older who were hospitalized were diagnosed with pneumonia. A quarter were transferred to intensive care, and 10.6 percent died in hospital.

The aftereffects can linger long after discharge. A study of patients aged 60 and older found that six months after hospitalization, 33 percent still had difficulty performing basic daily activities such as eating, dressing and using the bathroom, while 32 percent showed a decline in instrumental daily living skills such as grocery shopping and doing laundry.

The risks are even greater for those with underlying conditions. Compared with healthy adults, the hospitalization risk from RSV infection is roughly two to four times higher for asthma patients, three to 13 times higher for those with chronic obstructive pulmonary disease (COPD), and about eight times higher for heart failure patients. Among RSV patients aged 60 and older who were hospitalized, about 80 percent of COPD patients, about 50 percent of asthma patients and about 38 percent of heart failure patients experienced a worsening of their underlying condition during their hospital stay.

The annual RSV-related hospitalization rate among immunocompromised patients — including cancer patients who have undergone hematopoietic stem cell or organ transplants — is also about 4.7 times higher than that of the general adult population, at 862 cases per 100,000 people compared with 184 cases.

No antiviral treatment available, making prevention essential; vaccine Arexvy shows 95% efficacy in patients with chronic conditions

There is currently no established antiviral treatment for RSV infection in adults beyond supportive care to relieve symptoms, making vaccination the only and most reliable means of prevention.

Arexvy, one of the RSV vaccines available in South Korea, is approved for all adults aged 60 and older as well as high-risk adults between 18 and 59.

Arexvy is formulated with an adjuvant (AS01E) designed to maximize immune response in older adults, whose immunity tends to weaken with age. Clinical research shows the vaccine achieved 82.6 percent efficacy against lower respiratory tract disease in adults aged 60 and older, and 94.6 percent efficacy in those aged 60 and older with at least one underlying condition such as COPD, asthma, heart failure or diabetes.

A subgroup analysis of Korean participants confirmed similar efficacy and safety profiles to the global clinical trial results. The vaccine targets the F protein found in both RSV type A and type B, providing protection against both subtypes, and a single dose has been shown to maintain protection across three consecutive seasons.

Real-world evidence from the United States also demonstrated strong effectiveness, with an 83 percent reduction in hospitalizations and a 77 percent reduction in emergency room visits among adults aged 60 and older. On the basis of these clinical benefits, the Korean Society of Infectious Diseases and the US Centers for Disease Control and Prevention strongly recommend a single RSV vaccine dose for all adults aged 75 and older, as well as for adults between 50 and 74 who have underlying conditions or are immunocompromised.

The sharp rise in elderly hospitalizations this year points to an earlier-than-usual respiratory virus season that has emerged in the post-COVID-19 era. Experts say it underscores the urgent need to move beyond basic personal hygiene measures toward a proactive, vaccine-centered public health strategy focused on high-risk groups, particularly as South Korea enters a super-aged society.

"Chuseok is a time when family contact increases, and it also coincides with the period when respiratory viruses become more active, so extra caution is needed," said Jeong Dong-hyeok, a professor in the family medicine department at Severance Hospital. "When multiple generations gather, everyone should follow hygiene practices such as avoiding contact with others if they have respiratory symptoms. Adults aged 75 and older, and those aged 50 and older with chronic conditions such as heart failure or diabetes, should consult a specialist in early autumn — just before the season peaks — about getting vaccinated."


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