The Central Children's Hospital in Vietnam has issued a warning regarding the spread of Adenovirus at public swimming pools, following a report where four out of five children in a swimming class tested positive for the virus. This alarming situation underscores the potential health risks linked to public swimming environments, particularly during the summer months when many children gather for recreational activities.

Since the beginning of the year, the hospital has recorded 2,777 cases of Adenovirus, a threefold increase compared to the same period in 2025. In just the first few days of July 2026, an additional 383 children were admitted with the illness, indicating a rapid rise in cases.

Adenovirus is a common virus that can cause illness year-round, but its prevalence often spikes during transitional seasons or summer when children are more active outdoors and in close contact with one another. The virus primarily spreads through respiratory droplets when an infected person coughs or sneezes, but it can also be transmitted via contaminated surfaces, personal items, or unsanitary water sources.

Children swimming in contaminated water are at risk of infection through their eyes or by sharing personal items such as towels or drinking cups. The incubation period for the virus typically lasts between 8 to 12 days, and the disease can easily spread in crowded places like schools, playgrounds, and public pools.

The symptoms of Adenovirus can vary widely, with common signs including high fever, cough, sore throat, conjunctivitis (red eye), and gastrointestinal disturbances. Some children, especially older ones, may experience persistent high fever that does not respond well to standard fever-reducing medications.

If not properly monitored and treated, some cases can worsen, leading to complications such as pneumonia, which may require hospitalization. To mitigate the risk of infection, health experts recommend that parents take their children to healthcare facilities promptly if they exhibit symptoms such as high fever, prolonged cough, conjunctivitis, or gastrointestinal issues.

Parents should avoid self-medicating their children with antibiotics without a doctor's prescription. If a child shows signs of illness, such as fever, cough, or conjunctivitis, it is advisable to keep them at home and refrain from visiting public pools or crowded places to prevent spreading the virus to others.

Public facilities that attract large groups of children, such as schools, playgrounds, and swimming pools, should maintain rigorous cleaning and sanitation protocols for water, shared spaces, and surfaces. Management should ensure a clean and well-ventilated environment, monitor water quality, and regulate the number of participants to reduce the risk of Adenovirus transmission within the community.