From pneumonia to encephalitis: what dangerous complications Hong Kong flu leads to
Russia has seen a sharp increase in the incidence of respiratory infections, with the influenza A(H3N2) strain, known as the Hong Kong flu, dominating. The disease is characterized by high fever, as well as specific symptoms — acute pain in the ears and redness of the eyes. According to doctors, complications can be severe, including pneumonia, otitis media, myocarditis and lesions of the nervous system. Read more about the risks and preventive measures of the Hong Kong flu in the Izvestia article.
Which regions of Russia are affected by the Hong Kong flu
The Hong Kong flu is a strain of the influenza A(H3N2) virus first identified in 1968 in Hong Kong. It caused a global pandemic that spread rapidly around the world due to the virus' high contagiousness and ability to mutate rapidly. The virus entered Russia shortly after the outbreak, in late 1968 and early 1969, and has since regularly caused seasonal epidemics due to its strains. This type of flu is characterized by high morbidity and the ability to cause severe complications, especially in the elderly and people with chronic diseases.
In November 2025, Rospotrebnadzor recorded a steady rise in respiratory infections throughout Russia, with a particular concentration of cases of Hong Kong flu in the Far East, the Urals and Siberia. The number of cases is growing daily in the capital. Flu vaccination in Russia has reached about 52.9% of the population, which is more than 78 million people, but this is not enough to create collective immunity.
The increase in the incidence of influenza A(H3N2) really causes serious concern in the professional community, says allergologist, immunologist, rheumatologist and general practitioner of the NCC NCC No. 2 of the Russian National Research Medical University. Academician of B.V. Petrovsky" Elena Sycheva. According to the expert, strain A(H3N2), although not completely new, is characterized by high variability (antigenic drift).
Symptoms of Hong Kong flu
The Hong Kong flu begins suddenly — in the first 1-2 days after infection, the temperature rises sharply to 39-40 ° C, severe chills and general malaise appear. A person suffers from intense headache, often with pain in the eyes, aching muscles and joints, and weakness. Inflammation develops in the respiratory tract: dry cough, throat irritation, nasal congestion and redness of the mucous membranes. A special feature may be digestive problems such as nausea, diarrhea and abdominal pain. Doctors note specific symptoms, such as acute pain in the ears associated with swelling of the Eustachian tube, and redness of the whites of the eyes.
What is the danger of the Hong Kong flu?
According to Elena Sycheva, the most vulnerable groups are the elderly over the age of 65 with chronic diseases, young children, pregnant women, as well as people with weakened immune systems. Strain A(H3N2) is highly contagious and capable of causing severe forms of the disease, which is confirmed by the intensive circulation of the virus in closed groups and an increase in hospitalizations.
The infection is often complicated by bacterial inflammations, including pneumonia, bronchitis, otitis media, sinusitis and rhinopharyngitis. The strain is also capable of causing damage to the cardiovascular system, such as myocarditis and exacerbation of heart failure, as well as neurological complications such as meningitis and encephalitis. High fever and intoxication can lead to decompensation of chronic diseases.
Untimely treatment for help contributes to a severe course and even death, so doctors strongly recommend contacting specialists at the first sign of the disease and not self-medicating.
How to protect yourself from the Hong Kong flu
Timely vaccination remains the key to prevention, the doctor emphasized. All domestic and international vaccines relevant for the 2024/25 season contain antigens of strain A(H3N2), as well as A(H1N1) and B. The vaccine does not provide absolute protection, but it significantly reduces the severity of the disease and the risk of fatal complications, especially among at-risk groups. The optimal period for vaccination is September – October, however, even late vaccination in December – January may be useful, given the peak of the epidemic.
"The vaccine does not guarantee 100% protection against the disease, but it is extremely effective in preventing severe forms, complications and deaths, especially in high-risk groups. The optimal time for vaccination has already passed, but it's not too late to get vaccinated, since the peak of the epidemic often falls in January – February," Sycheva explained.
In addition, non-specific protective measures must be observed: the use of masks in crowded places and medical institutions, careful hand hygiene, limited contact with patients, regular ventilation and humidification of the air. If the first symptoms appear — a sharp rise in temperature, severe headache, aches and dry cough — you should immediately consult a doctor and refrain from self-medication, especially from taking antibiotics without prescription, as they are ineffective against the virus.
Переведено сервисом «Яндекс Переводчик»
