Influenza (flu) is an acute viral infectious disease. It spreads usually as an epidemic, in our climate most often in the autumn and winter season and in early spring. Epidemics occur usually cyclically every 2-3 years. Influenza symptoms are often mistaken for common cold symptoms and vice versa. However, the disease may be very dangerous; according to the data of the World Health Organization, every year several tens of thousands of people die due to this disease. The virus is transmitted from the infected to a healthy person by the droplet route, i.e. in droplets of airway secretions during sneezing, cough, greeting each other, and even during a conversation. Staying in large groups of people contributes to the infection. A case of an influenza infection of the majority of an aeroplane passengers during one several-hour flight has been described.
The disease symptoms appear within approximately two days of incubation (or earlier). They are predominantly fever (often above 39°C), chills, headache, muscle pain, joint pain, symptoms of mucosal irritation (running nose, cough, sore throat – due to inflammation), asthenia. The symptoms are of various intensity and duration, depending on the patient’s resistance, age, general condition, coexisting diseases, and, of course, on the virus and its virulence. Damaging of the respiratory epithelium contributes to infections by pathogenic bacteria and the virus itself may damage also various internal organs. Influenza diagnosis is made on the basis of the severity of the above-mentioned symptoms which are much less intense or are absent in the case of common cold.
Treatment
Treatment is solely conservative and includes mainly staying in bed at home until the disease symptoms resolve and taking drugs alleviating them (antipyretic, analgesic, and antitussive medicines, vitamins, etc.). If secondary bacterial infection is suspected, an antibiotic is added to the treatment.
Prevention
For several years, we have had the possibility of being vaccinated against influenza. Unfortunately, such vaccination protects us against catching this disease only for one year. This is due to high antigenic variability of the influenza virus which changes its structure every year and appears to be an entirely new virus for our immunological system (the so-called antigenic shift). Therefore, every year pharmaceutical companies, on the basis of the recommendation of the World Health Organization (WHO), prepare new vaccines containing split viral strains to which we will be exposed in the given influenza season. All pharmaceutical companies have at their disposal the same set of viruses in the given year. WHO prepares two sets: one for the northern hemisphere and the second one for the southern hemisphere, and no case has occurred of mistaken preparation of the set. The vaccine contains a culture of the influenza virus deprived of its pathogenic activity.
Why is it worth to be vaccinated and who should do that?
You should vaccinate yourself especially if you work with large groups of people, when you are at risk of immune deficiency in relation to your occupation, and when you have chronic diseases due to which the body may not be able to cope with the infection. And thus doctors, nurses, old people’s home employees and public service employees: ticket collectors, cashiers, police officers, soldiers, teachers, kindergarten employees, and journalists should get vaccinated. This also applies to babysitters, shop assistants, craftsmen, construction workers and people working outdoors, and furthermore to the following:
- persons aged more than 65 years
- persons with respiratory disorders (e.g. with asthma)
- persons with cardiovascular insufficiency
- persons with deficient function of the immune system
- chronically ill persons, e.g. persons with renal function impairment, diabetes
Severe influenza complications All influenza symptoms are not dangerous for generally healthy people, apart from more than one week of immobilisation at home. However, in some persons life-threatening complications may develop in the course of this disease.
Potential complications of influenza include:
- Pneumonia, bronchitis
- Otitis media
- Sinusitis
- Exacerbation of chronic lung diseases
- Aggravation of coronary disease symptoms
- Aggravation of cardiac failure symptoms
- Aggravation of asthma symptoms
- Deregulation of diabetes
- Renal function impairment
- Myocarditis and pericarditis
- Cerebritis
- Meningitis
- Pregnancy complications – risk of miscarriage
Is it necessary to vaccinate children? The statistics are relentless. Children below 14 years of age represent 45 percent of flu patients and half of the patients admitted to hospitals due to influenza. Therefore, if your child attends a school, a kindergarten, or a nursery, you absolutely should vaccinate it. The high risk group includes especially young children below five years of age because the course of influenza in their case is particularly severe, and each complication, e.g. otitis media, is a serious disease. Children below 6 months of age should not be vaccinated.
Contraindications to vaccination 1. Acute disease with fever
2. Period of exacerbation of a chronic disease
3. Hypersensitivity to vaccine ingredients (neomycin, formaldehyde)
4. Hypersensitivity to hen egg white
5. History of Guillain-Barre syndrome (neurological disorder)
6. Less than 6 months of age
7. Excessive post-vaccination reactions following the previous influenza vaccination