Seasonal influenza is an acute respiratory infection caused by influenza viruses. The main pathogens are influenza A (H3N2), influenza A (H1N1), influenza B and influenza C. The disease is highly contagious, spreads rapidly, and can cause epidemics and pandemics. The disease is transmitted through the respiratory tract, through small droplets of nasal and throat secretions containing influenza viruses due to coughing, sneezing, etc. The rate of spread is stronger when there is direct and close contact, especially in crowded places such as schools and kindergartens. In cold and humid weather conditions, people's respiratory cells are vulnerable, increasing susceptibility to the disease. Symptoms of seasonal influenza include fever, headache, muscle aches, runny nose, sore throat, fatigue, and cough. Cough is often severe and prolonged. It may be accompanied by gastrointestinal symptoms (nausea, vomiting, diarrhea), especially in children. Usually the disease is mild and recovers within 2-7 days. In children and the elderly, people with chronic heart, lung, kidney, metabolic, anemia, or immunocompromised diseases, the disease can progress more severely.

Influenza can leave complications: ear infections, bronchitis, pneumonia, encephalitis, and even death. According to studies around the world, seasonal flu can:

- Increase the risk of heart attack, myocardial infarction up to 10 times in cardiovascular patients;

- Increase the risk of blood sugar instability by 75% in diabetic patients;

- Increase the risk of exacerbations of chronic obstructive pulmonary disease, thereby increasing the rate of premature death in these patients.

In Vietnam, influenza occurs sporadically throughout the year, with 600,000 - 1,000,000 cases of seasonal flu recorded each year. The disease often increases in the cold season and the transition from summer to autumn, winter to spring. The main causes are influenza A (H3N2), influenza A (H1N1) and influenza B viruses. Cases tend to increase in winter and spring.

In Phu Yen province, according to the infectious disease surveillance system of the provincial Center for Disease Control, seasonal influenza has recorded a high number of cases each year. In the period 2017-2024, an average of over 2,000 cases were recorded each year. In 2019, 02 deaths were recorded, and in 2024, 01 case was recorded (chart 1).

During the year, influenza is most detected in the first months of the year, the changing seasons, which is also the time of Tet when there are many trading, shopping, and entertainment activities, creating conditions for disease transmission.

There is no specific treatment for seasonal influenza, only symptomatic treatment when infected. Influenza vaccination is considered the most effective method of preventing seasonal influenza. Flu vaccines have the ability to create antibodies to protect the body against influenza virus attacks. The protection ability of influenza vaccines after injection can reach 97%. Children from 6 months old, pregnant women, the elderly, and people with chronic diseases are the subjects that need to be vaccinated against influenza every year because they are at high risk of influenza and are more likely to have severe complications than others. According to the World Health Organization, annual influenza vaccination not only helps prevent influenza, but also prevents complications caused by influenza:

Reduce hospitalization and death rates by 35% in cardiovascular patients.
Reduce mortality rates by 58% in diabetic patients.
Reduce mortality rates by 70% in people with chronic obstructive pulmonary disease
Currently, it is the transitional season, cold weather combined with humid rain is a favorable condition for respiratory diseases to increase, including seasonal influenza. To proactively prevent seasonal flu, the Department of Preventive Medicine, Ministry of Health recommends that people do the following:

1. Ensure personal hygiene, cover your mouth when sneezing; wash your hands regularly with soap; clean your nose and throat daily with salt water.

2. Wash your hands regularly with soap and clean water.

3. Keep your body warm, eat enough nutrients to improve your health.

3. Get vaccinated against seasonal flu to strengthen your immunity against flu.

4. Limit contact with flu patients or suspected cases when not necessary; use medical masks when necessary.

5. People should not arbitrarily buy and use antiviral drugs (such as Tamiflu) but must follow the instructions and prescription of a doctor.

6. When having symptoms of cough, fever, runny nose, headache, fatigue, go to a medical facility immediately for timely examination and treatment.

In addition, in the coming time, weather conditions combined with increased travel and communication, the demand for buying, selling and slaughtering poultry to serve the holidays will increase sharply, leading to the risk of dangerous avian influenza outbreaks such as influenza A(H5N1), influenza A(H7N9), people need to:

1. Do not eat sick, dead poultry, poultry products of unknown origin; ensure food and water are cooked thoroughly; wash hands with soap before eating.

2. Do not slaughter, transport, buy and sell poultry and poultry products of unknown origin.

3. When discovering sick or dead poultry, absolutely do not slaughter and use it, but immediately notify the local authorities and veterinary units in the area.

4. When there are signs of influenza such as fever, cough, chest pain, difficulty breathing related to poultry, go immediately to a medical facility for timely advice, examination and treatment.

PleaseGet your annual flu vaccine today!

MSc. Dr. Nguyen Thi Thang

Deputy Head of the Department of Infectious Disease Control - International Health Quarantine

Phu Yen Center for Disease Control.