Influenza – vaccines and treatment

Influenza is a highly contagious disease. It is associated with significant morbidity and mortality. Therefore it is extremely important to put more attention to proper prevention and treatment procedures.

There are three influenza types: A, B, and C. A and B types are responsible for human flu epidemics. Influenza viruses are categorized based on surface antigen subtypes. There are two significant glycoproteins attached to the lipid surface of the virus: hemagglutinin (HA) and neuraminidase (NA). HA helps the virus to enter into the host cell, whereas NA cleaves and releases virions. Rapid mutations within the glycoprotein subtypes make influenza viruses extremely demanding enemies.
Typical influenza symptoms include fever (over 38 degrees Celsius), chills, body aches, fatigue, rhinitis, sore throat, cough, vomiting, and diarrhea. The most contagious period of the disease is day 2 or 3. Viral shedding performs via direct transmission, for example sneezing, coughing etc., or contact via hands or mouth.

The most effective way of preventing influenza is vaccination. There are trivalent vaccines available on the market – they contain three strains of different subtypes of influenza viruses (two strains of type A and one strain of type B). Vaccination against influenza is crucial especially for members of high-risk groups, such as medical staff, teachers, pregnant women, children from six months to 18 years of age and others who would be likely to expend complications from influenza.
The adjunctive agents for the influenza prevention are antiviral drugs: adamantane derivatives (amantadine, riman­tadine) and neuraminidase inhibitors (oseltamivir, zanamivir). The adamantane derivatives have activity only against influenza type A. Their side effects include insomnia, headaches, irritability, anxiety, and other central nervous system disorders. The neuraminidase inhibitors are active against influenza type A and B. In 2009 a new antiviral drug (also a neuraminidase inhibitor) called peramivir was released by FDA in the USA.

As in the case of antibiotic resistance of bacteria, there is a great danger of the virus strains gaining resistance to the antiviral medications. Therefore it is extremely important to use them responsibly.

EXERCISE. CHOOSE TRUE OR FALSE.
1. Neuraminidase is one of the glycoprotein attached to the surface of the influenza virus.
2. Trivalent vaccines contain type A, B, and C influenza strains.
3. Children of all age have to be vaccinated.
4. Rimantadine is active against type A and B influenza.
5. Peramivir is a new neuraminidase inhibitor.

Glossary:
• morbidity [mɔrˈbɪdɪti] – zapadalność, zachorowalność
• mortality [mɔrˈtælɪti] – umieralność
• epidemic [ɛpɪˈdɛmɪk] – epidemia
• hemagglutinin [hiːməˈɡluːtɪnɪn] – hemaglutynina
• neuraminidase [njʊərəˈmɪnɪdeɪz] – neuraminidaza
• fatigue [fəˈtig] – zmęczenie
• rhinitis [raɪˈnaɪtɪs] – nieżyt nosa
• to shed [tə ʃɛd] – rozsiewać
• strain [streɪn] – szczep
• adjunctive [əˈdʒʌŋktɪv] – pomocniczy, dodatkowy
• adamantane [ædəˈmænteɪn] – adamantan
• derivative [dɪˈrɪvətɪv] – pochodna
• amantadine [əˈmæntədin] – amantadyna
• rimantadine [rəˈmæntədin] – rymantadyna
• oseltamivir [oʊsɛlˈtæməvɪər] – oseltamiwir
• zanamivir [zəˈnæməvɪər] – zanamiwir
• resistance [rɪˈzɪstəns] – oporność
• to gain [tə geɪn] – nabywać
• to be vaccinated [tə bi ˈvæksəneɪtɪd] – być szczepionym, poddać się szczepieniu

Correct answers: true, false, false, false, true