On 23/12, a 6-year-old girl with A/H3N2 flu was treated at the National Children's Hospital for myocarditis complications. She required intensive care, including mechanical ventilation, ECMO, and antiviral medication. Previously, Tam Anh General Hospital Hanoi also reported a 17-year-old patient with acute myocarditis caused by B flu. Doctors note that myocarditis typically appears from the 4th to 7th day after flu symptoms begin. Patients may experience fever, chest pain, palpitations, shortness of breath, and fatigue.

Doctor Le Thi Truc Phuong, a Medical Specialist at the VNVC Vaccination System, explained that myocarditis is the inflammation of all or part of the heart muscle, often caused by viruses. Flu-induced myocarditis usually manifests from the 4th to 7th day after symptom onset, sometimes earlier. Patients might have fever, chest pain, a rapid heartbeat, shortness of breath, and fatigue. Without timely diagnosis and treatment, the condition can become dangerous.

The flu virus can cause myocarditis through hai mechanisms. Mot is direct attack on heart cells, leading to poor cardiac contraction, arrhythmias, and circulatory failure. Hai is the overactivation of the immune response, creating a "cytokine storm" that results in systemic inflammation, cardiac dysfunction, and heart failure.

The 6-year-old child required treatment at the Intensive Care Department, National Children's Hospital. Photo: National Children's Hospital.

Beyond myocarditis, flu patients can experience other complications such as pneumonia, bronchitis, respiratory failure, and meningitis. Damage to the respiratory tract lining and reduced immunity due to flu also create opportunities for other viral and bacterial pathogens like pneumococcus, respiratory syncytial virus (RSV), Hib, and Staphylococcus aureus to cause more severe illness.

Flu also increases the risk of stroke and myocardial infarction by 5-10 times during the 1-7 days following flu infection. This occurs because the body's inflammatory response makes atherosclerotic plaques in blood vessels more prone to rupture, forming blood clots. These clots can block heart arteries, leading to myocardial infarction, or obstruct brain blood vessels, resulting in a cerebral stroke.

According to Doctor Phuong, flu easily spreads through the respiratory tract via direct contact or conversation with an infected person within a 2-meter radius. Healthy individuals can also contract the virus by inadvertently touching contaminated hard surfaces such as tabletops, computers, phones, or door handles.

Currently, the southern region is experiencing erratic weather. The northern region is in winter, with decreasing temperatures and humidity, creating a favorable environment for the flu virus to develop and persist longer. Towards the end of the year, people's demand for travel, shopping, and attending parties or festivals increases. Gathering in crowded, enclosed spaces further raises the risk of pathogen transmission.

To prevent flu, people should maintain a varied diet, increase fruit and vegetable intake, and drink sufficient water during cold weather. It is important to keep the body warm, especially the neck, chest, and limbs. Practicing personal hygiene, such as frequent handwashing with clean water and soap, and carrying hand sanitizer when outdoors, is essential. Regular, moderate exercise is also beneficial. Additionally, consistent annual flu vaccination is an effective preventive measure.

Children are brought by parents for flu vaccination at VNVC Nha Be Vaccination Center, TP HCM. Photo: Hoang Duong.

There are various types of flu vaccines, suitable for children aged 6 months and older, and adults, effectively protecting against common A and B flu strains. Children from 6 months to under 9 years who have not been vaccinated before need hai doses, given mot month apart. Children aged 9 years and older and adults require mot dose, with a booster shot needed mot dose every year. Research indicates that flu vaccination reduces the risk of hospitalization and death by 90%, and lowers the risk of myocardial infarction by 15-45%.

Individuals with underlying conditions or those at high risk of severe flu infection and complications should consult a doctor at a vaccination center for early booster shots to ensure timely health protection.

Pregnant women can receive the flu vaccine at any point during pregnancy, ideally from the 4th month onwards. The vaccine helps protect maternal health, reducing the risk of flu complications for the mother, while also transferring passive antibodies to protect the infant during the early months of life.

Hoang Duong