THE the flu it is a very common acute viral illness that affects thousands of people annually. Only in the United States, about 20 to 40 thousand people die annually from this disease.In general, it is self-limited, however, severe cases of this disease can be observed, such as the flu caused by the influenza A(H3N2).
→ Influenza
As we know, flu is caused by a virus called influenza, which has more than one type. Influenza is an RNA virus that is characterized by constantly changing and having a great capacity to adapt. We can classify it into three basic types: A, B and C.
Influenza A and B are the types responsible for epidemics, and type A is the cause of large pandemics and serious infections requiring interaction or fatal complications. Type C, on the other hand, is not related to epidemics and generally leads to mild infections.
→ Influenza A
Influenza A is the type with the greatest variability and can be divided into subtypes. The subtypes are differentiated by their glycoproteins found on the surface, which are called
hemagglutinin (H) and neuraminidase (N). In total, there are 15 types of hemagglutinin and nine of neuraminidase, however, the best known are the hemagglutinins H1, H2 and H3 and two neuraminidases, N1 and N2.→ Influenza A (H3N2)
H3N2 is a type of influenza type A, of human origin, which has H3 and N2 surface antigens..This is a type of virus that undergoes constant mutations in its hemagglutinin glycoprotein, which affects the action of human antibodies against the disease.
This virus gained prominence after causing several deaths in the United States in the early winter of 2018. In that country, there was a predominance of the circulation of the influenza A (H3N2) virus, which was associated with a higher number of hospitalizations and deaths due to infection. The occurrence of death occurred especially among the elderly, children and chronically ill.
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In the Epidemiological Report of the Health Surveillance Secretariat of the Ministry of Health, which comprises the epidemiological weeks (SE) from 1 to 13 of 2018, 28 deaths are reported from the influenza virus, ten of which caused by influenza A (H3N2). These data raise the alert regarding this subtype, which has caused several deaths in the United States.
→ Flu vaccine
THE vaccine Against the the flu available in Brazil is produced from the dead virus, being called, therefore, inactivated. Vaccines currently available in our country protect against strain A (H1N1), strain A (H3N2) and strain B (Yamagata or Victoria strain).There are also quadrivalent vaccines that, in addition to the types of influenza A, protect against both types of influenza B.
→ Ways to avoid contagion
The flu usually causes fever, headaches, dry cough, fatigue, muscle aches, sore throat and chills. In severe cases, it can lead to complications that can be fatal and, therefore, must be prevented. Among the forms of prevention, we can highlight:
Vaccination;
Always wash your hands with soap and water, especially before meals;
Always cover mouth and nose when coughing and sneezing;
Do not share personal items such as glasses and bottles;
Avoid environments with large agglomerations;
Keep environments ventilated;
Avoid contact with a patient;
- Adopt healthy eating habits.
By Ma. Vanessa Sardinha dos Santos
Would you like to reference this text in a school or academic work? Look:
SANTOS, Vanessa Sardinha dos. "Influenza A(H3N2)"; Brazil School. Available in: https://brasilescola.uol.com.br/biologia/influenza-h3n2.htm. Accessed on June 27, 2021.
