As the wave of respiratory viral infections rises sharply and seasonal flu—dominated by influenza A (H3N2)—drives both children and adults to doctors and hospitals, the new year has begun. According to the National Public Health Organization (EODY), coronavirus levels remain stable, while flu and respiratory syncytial virus (RSV) cases are recording a significant increase.

Children served as the reservoir of viral infections during the last ten days of December, fueling transmission within households over the holiday period. The elderly and those belonging to vulnerable groups are proving to be the weakest links in the transmission chain, with experts urging vaccination even now, so that people are protected against flu, coronavirus and RSV, which are expected to circulate intensely for the next three months or more.

Cases in children

The hundreds of visits—up to 550 children to Emergency Departments—recorded from Christmas to New Year during on-call shifts at the two Pediatric Hospitals “Aglaia Kyriakou” and “Agia Sofia” reflected the increased viral load circulating in the community and foreshadowed the wave of infections among the adult population.

“Children are the reservoir of winter respiratory infections,” pediatrician and vice president of the Association of Self-Employed Pediatricians of Attica, Anna Pardali, tells THEMA. As she explains regarding flu, “this is not a viral illness that subsides immediately, especially in children. Recovery time can last several days, while full restoration of the body requires even more time. Even when the fever subsides and the child appears improved, the immune system remains strained. For this reason, at least one to ten days should pass from the onset of symptoms before returning to intense activities or close social contact.” As she notes, in conditions of increased viral circulation, a child who has not fully recovered and is exposed to a new virus may develop complications.

High fever (above 38°C), chills, muscle aches, malaise and muscle weakness, cough, sore throat, runny nose and intense headache are the main symptoms of flu, which this year are additionally characterized by greater intensity and longer duration.

“Data show an upward trend in seasonal flu. After cases in minors in December, infections are now being recorded in adults, mainly in people over the age of 65. The holiday period affects circulation and transmission of viral infections. The flu wave is expected to continue its upward course, with adults at the center,” Dimitris Paraskevis, Professor of Epidemiology at the Medical School of the National and Kapodistrian University of Athens and member of the EODY Board, tells THEMA.

Thessaloniki, Ioannina, Larissa and Patras are the four cities where, according to EODY’s epidemiological surveillance of wastewater, the viral load of influenza A showed a rapid increase up until last Thursday. The largest increase was recorded in Thessaloniki (+124.3%) and Ioannina (+115.3%), while Larissa and Patras also showed very high levels with upward trends (+68.9% and +16.3% respectively). At the same time, coronavirus circulation remains stable, with EODY data showing increases in Athens and Alexandroupoli. During the same period, 121 hospital admissions due to Covid-19 infection were reported.

In the last week of 2025, admissions for flu or its complications doubled compared to the immediately preceding week: 497 admissions were recorded versus 235 before Christmas. Overall, during this flu season, 15 cases requiring ICU hospitalization and three deaths have been recorded. Five of the ICU admissions occurred during Christmas week.

“From the data available so far, it appears that despite increased transmissibility, cases of severe illness from flu are reduced in Greece. This may be attributed to increased vaccination coverage among vulnerable and elderly populations,” notes Mr. Paraskevis. According to Ministry of Health data, approximately 2.4 million people have been vaccinated against flu this year, compared to 1.8 million last year.

He emphasizes the importance of vaccinating the elderly and vulnerable groups against flu, RSV and coronavirus, as disease severity is significantly reduced and the risk of serious complications is limited. “Vaccination remains critical even now. Those who belong to high-risk groups should be vaccinated against viruses that cause life-threatening infections,” he stresses, adding the importance of timely medical intervention when symptoms appear, so that antiviral treatment can be administered promptly where required and hospitalization can be avoided.

Hospitalizations

According to data from Evangelismos Hospital, a significant proportion of severe hospitalizations are linked to viral infections. Data from the past two years, collected by EKPA Professor of Pulmonology Paraskevi Katsounou, show a high number of hospitalizations as well as increased mortality. Specifically, from May 2023 to June 2025, more than 4,500 patients were hospitalized with lower respiratory tract infections. In-hospital mortality reached 15.8% for patients with RSV and 12.5% for those hospitalized with flu. The majority of those who died belonged to vulnerable groups, such as smokers or patients with chronic obstructive pulmonary disease (COPD).

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