Influenza is a severe viral infection that affects men, women and children of all ages and nationalities. Influenza is associated with a high mortality rate, especially in young children and the elderly. Influenza epidemics occur every year, usually during the cold season, and affect up to 15% of the world's population.
Influenza is an infectious disease that is characterized by various lesions of the respiratory tract and manifests itself in a variety of respiratory symptoms. Epidemics occur during the cold season and affect up to 15% of the world's population, often leading to death in patients at risk. However, despite this, the idea of influenza infection as a mild illness is still common. The difficulty in refuting this myth is partly due to the fact that many use the term “flu” not only to refer to a laboratory-confirmed disease, but also to refer to a wide range of other viral diseases, from the common cold (ARI) to gastroenteritis (“stomach flu”). But in fact, this is a severe viral infection that affects the respiratory tract and requires timely treatment.
- Routes of transmission of the virus
- What complications may arise
- The first signs in an adult
- Treatments for influenza in adults
- Recovery after illness
Influenza (French grippe), influenza is an acute, highly contagious respiratory viral infection with an airborne transmission mechanism, caused by influenza viruses type A, B and C (family Orthomyxoviridae, genus Influenzavirus).
This infection has a tendency to spread epidemically and affects all age groups of the population in various geographical conditions. The disease is characterized by a short incubation period, a rapid cyclic course, the presence of intoxication and catarrhal syndromes with predominant damage to the epithelium of the mucous membrane of the upper respiratory tract. In the International Classification of Diseases, Injuries and Causes of Death, nosological forms of influenza are included in the group “Respiratory diseases”.
Today, the continuous circulation of disease viruses and the emergence of new strains of animal origin pose a constant danger to the health of the population of all countries. It is believed that 5-10% of adults and 20-30% of children get sick every year. At the same time, complications develop in 10-15% of patients, especially if they do not treat it. Severe influenza may be accompanied by damage to the lower respiratory tract with signs of respiratory failure, pulmonary edema, vascular collapse, cerebral edema, hemorrhagic syndrome and the addition of secondary bacterial complications. Among hospitalized patients, often in risk groups, this figure can reach 30%.
The annual mortality rate due to complications of influenza is 7.5-23 people per 100,000 population, with the majority of deaths occurring in people over 65 years of age. According to the World Health Organization (WHO), at least 600,000 patients die every year from influenza infection. This figure is the highest among risk groups. The global economy is suffering enormous damage from this disease. Approximately 50% of all cases of sick leave are due to acute respiratory viral infections, including influenza.
How does flu infection occur?
The source of an infectious disease can be a sick person with clinically obvious and atypical (implicit) manifestations of the disease. The greatest infectiousness is observed during the first 3 days from the onset of clinical manifestations. Isolation of the pathogen lasts approximately 5-7 days in an uncomplicated form (faster formation of immunity and elimination of the virus) and up to three weeks in a severe and complicated form (slow formation of immunity, including due to a possible initial weakening of protective mechanisms - concomitant diseases, age ).
The transmission mechanism is airborne droplets (aerosol route), contact route is possible (when using shared utensils, kissing, contaminated hands). Autumn-winter seasonality with an epidemic component is quite typical, repeating at approximately the same interval. Sporadic incidence of ARVI is observed at any time of the year.
Recent studies have shown that influenza viruses live on human hands for 5 minutes. If during this time a person touches some things, the viruses transfer to them and live there much longer. They last for 24 to 48 hours on metal and plastic, and ten days on glass. According to statistics, one flu patient on average infects five people.
WHO activities
WHO, through the WHO GISRS system and in collaboration with other partners, monitors influenza activity globally, makes recommendations on seasonal influenza vaccine formulations twice a year for the northern and southern hemispheres, and assists countries with tropical and subtropical climates in the selection of vaccine products (for northern and southern hemispheres) and decisions regarding the timing of vaccination campaigns and supports Member States in developing prevention and control strategies.
WHO works to strengthen national, regional and global capacity to respond to influenza (including diagnosis, antiviral susceptibility monitoring, disease surveillance and outbreak response), increase vaccination coverage in high-risk populations and ensure preparedness for next influenza pandemic.
(1) Estimates of US influenza-associated deaths made using four different methods. Thompson WW, Weintraub E, Dhankhar P, Cheng OY, Brammer L, Meltzer MI, et al. Influenza Other Respi Viruses. 2009;3:37-49
(2) Global burden of respiratory infections due to seasonal influenza in young children: a systematic review and meta-analysis. Nair H, Abdullah Brooks W, Katz M et al. Lancet 2011; 378: 1917–3 (3) WHO recommended surveillance standards, Second edition.
Complications of influenza
With prolonged progression of the disease, as well as with non-compliance with the doctor’s instructions - for example, if bed rest is violated during the acute period of the disease, with premature interruption of antiviral treatment, the development of serious, life-threatening complications from various organs and systems is possible.
Flu can lead to:
- otitis media,
- sinusitis,
- pharyngitis,
- laryngitis,
- tracheitis,
- neuralgia,
- sore throat,
- bronchitis,
- pneumonia,
- pulmonary edema,
- meningitis,
- respiratory failure
- a number of other dangerous diseases of the cardiovascular, excretory and respiratory systems.
After suffering from pneumonia, residual effects in the form of bronchiectasis and pneumosclerosis often persist.
Pregnant women infected with influenza virus or ARVI are also at high risk of complications and mortality. Mortality rates among pregnant women with severe influenza infection vary in different countries and in Russia are 0.3%. Most deaths occur in pregnant women in the third trimester. Healthy expectant mothers in the third trimester have a risk of severe respiratory infection comparable to that of nonpregnant patients with chronic comorbidities.[ii]
Pathogen
There are 4 types of seasonal influenza viruses - types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of illness.
Influenza A viruses are divided into subtypes according to combinations of hemagglutinin (HA) and neuraminidase (NA), proteins on the surface of the virus. Currently, influenza viruses of subtypes A(H1N1) and A(H3N2) are circulating among people. A(H1N1) is also referred to as A(H1N1)pdm09 because it caused the 2009 pandemic and subsequently replaced the seasonal influenza A(H1N1) virus that circulated before 2009. Only influenza A viruses are known to cause pandemics.
Influenza B viruses are not divided into subtypes, but can be divided into lineages. Currently circulating influenza B viruses belong to the B/Yamagata and B/Victoria lineages.
Influenza C virus is less common and usually causes mild infections. Therefore, it does not pose a public health problem.
Group D viruses mainly infect cattle. According to available data, they do not infect people or cause disease in them.
The first signs of influenza in adults
In clinical practice, according to WHO recommendations, it is customary to distinguish between complicated and uncomplicated forms of influenza, as well as forms of the disease depending on the severity of the disease: mild, moderate and severe.[iii]
With influenza, the incubation period is very short and averages 48 hours from infection to the very first symptoms.[iv] The disease usually begins suddenly. The causative agents of the disease, viruses of types A and B, are characterized by aggressiveness and an extremely high reproduction rate, therefore, within a matter of hours after infection, the virus leads to deep damage to the mucous membrane of the respiratory tract, opening up opportunities for bacteria to penetrate it.
Almost always after infection, catarrhal symptoms and signs of intoxication appear. In some cases, hemorrhagic disorders are noted - pathological conditions characterized by increased bleeding and manifested by an increase in the number of red blood cells in the urine, nosebleeds, and blood in the sputum.
Intoxication is manifested by the following flu symptoms in adults:
- elevated body temperature. With a mild degree of the disease, it usually does not exceed 38oC; at average – 39-40oС; in case of severe disease, the temperature may exceed 40oC;
- headache in the eye area, especially when moving the eyeballs;
- chills, which is a protective reaction of the body aimed at preserving heat and reducing its loss;
- pain in muscles, joints, lower back and legs;
- general malaise and weakness;
- loss of appetite;
- Sometimes there may be nausea and vomiting.
At the very beginning of the disease, as a rule, there is no severe runny nose with copious colored discharge, no sore throat, no cough.
With influenza in adults, symptoms and treatment can vary significantly (which is determined by the type of virus, the state of the immune system of the infected person and many other factors), but in general the clinical manifestations of the disease are similar. Some patients have atypical symptoms or an atypical clinical picture of the disease (for example, absence of fever).
Mild form of flu
In mild forms of the disease, the symptoms of general intoxication are mild. Body temperature rarely reaches 38oC and usually normalizes after 2-3 days. There is no threat to the patient's life.
Moderate form of influenza
The most common flu is of moderate severity, in which severe symptoms of general intoxication are observed, as well as signs of damage to the upper respiratory tract. The body temperature rises to 39-40oC and remains at this level for several days, the nose is stuffy, and a cough may bother you. If therapy is started in a timely manner and there are no complications, there is no threat to the patient’s life.
Severe flu
A severe form of influenza most often develops quite quickly, within a few hours. Intoxication syndrome leads to an increase in body temperature to 40oC and above. Patients are bothered by severe headaches and joint pains, photophobia. Fever can persist for a week, and developing complications from the respiratory and cardiovascular systems can pose a threat to the patient’s life.
A hypertoxic (fulminant) form of influenza is also sometimes found. It is characterized by an acute onset of the disease and rapid damage to the central nervous system, heart and lungs. In the absence of emergency medical care, death is possible.
In most cases, the diagnosis is made based on the symptoms of the disease. [v] Laboratory diagnostics - early and retrospective - are carried out to confirm the clinical diagnosis, differentiate influenza from acute respiratory viral infections of other etiologies and for epidemiological purposes.
Diagnostics
In most cases, human influenza is clinically diagnosed. However, during periods of low activity of influenza viruses and in the absence of epidemics, infection caused by other respiratory viruses, such as rhinovirus, respiratory syncytial virus, parainfluenza virus, and adenovirus, may also present as influenza-like illness, making it difficult to clinically differentiate influenza from other pathogens.
Adequate respiratory samples must be collected and a laboratory diagnostic test performed to make a definitive diagnosis. The first critical step for laboratory detection of influenza viral infections is the proper collection, storage, and transportation of respiratory specimens. Typically, laboratory confirmation of influenza viruses in secretions from the throat, nose, and nasopharynx or in aspirates or tracheal washings is performed by direct detection of antigens, virus isolation, or detection of influenza-specific RNA by reverse transcriptase polymerase chain reaction (RT-PCR). There are a number of laboratory manuals published and updated by WHO (3).
Rapid diagnostic tests are used in clinics to detect influenza, but they have low sensitivity compared to RT-PCR methods and the reliability of their results depends largely on the conditions in which they are used.
Treatment of influenza in adults
When you have an influenza infection, bed rest is very important. Attempting to carry the disease “on your feet” will only make you feel worse and will contribute to the infection of others. During an influenza infection, doctors recommend drinking a lot - the heat causes sweating, and, as a result, greater loss of moisture. Contrary to popular belief, very hot drinks are contraindicated - burns to the mucous membranes of the larynx make them vulnerable to bacterial infections. The drink should be warm. It is not advisable to drink coffee - it increases heart rate and can worsen the condition. Maintain a comfortable temperature in the room, humidify the air and do not forget about regular ventilation.[vi]
The following medications are used to treat influenza:
- symptomatic remedies - antipyretics and antihistamines, drops for the common cold.
- etiotropic drugs are drugs that act on the causative agent of the disease. This group includes antiviral agents that fight the virus at different stages of its life cycle and prevent its spread.
Use of the drug VIFERON for influenza
One of the antiviral drugs that helps restore the immune system and has a wide spectrum of antiviral activity is the drug VIFERON. Recombinant interferon alpha-2b, which is part of this drug, prevents the synthesis of viral DNA and blocks the reproduction of the virus, and also helps restore immunity. It is identical to human interferon alpha-2b, but is produced using modern technology without the use of donor blood.
The drug, which is available in the form of suppositories, gel and ointment, was developed as a result of fundamental research in the field of immunology, which has proven that in the presence of antioxidants (vitamins C, E), the antiviral effect of interferon is enhanced. The drug in the form of suppositories (suppositories) can be used during pregnancy (from the 14th week of gestation), as well as during breastfeeding, for the treatment of newborns, starting from the first days of a child’s life, and the elderly.
The inclusion of the drug VIFERON rectal suppositories in the complex therapy of influenza in adults contributes to:
- a decrease in body temperature to normal 24 hours after the start of use in 48.6% of patients;
- a decrease in body temperature to normal on the second day after the start of use in 82.9% of patients;
- reducing the total duration of intoxication symptoms (by an average of 2 times);
- shortening the duration of the febrile period to 1.53 days (control group 3.55 days).1
The antiviral drug VIFERON Gel can also be used for the treatment and prevention of ARVI and influenza for pregnant and lactating women, as well as newborn children, starting from the first days of life, and the elderly. When applied externally and locally, systemic absorption (the physiological process of absorption, that is, the penetration of medicinal substances into the blood and lymph) is low and the drug has an effect only at the site of the lesion.
Use of the drug VIFERON for the prevention of influenza
In order to protect yourself from acute respiratory viral infections and influenza infections, you need to apply a strip of gel approximately 0.5 cm long to the nasal mucosa 2 times a day as a preventive measure. Course duration is 2-4 weeks. For the treatment of ARVI, including influenza infection, including those complicated by a bacterial infection, the application of VIFERON gel must be repeated 3-5 times a day for 5 days.
VIFERON Ointment for the treatment of influenza and other acute respiratory viral infections is applied in a thin layer to the mucous membrane of the nasal passages 3 times a day. The amount of the drug is one pea with a diameter of 0.5 cm, the approximate course of treatment is 5 days.
Sources of the disease
The viral nature of influenza is characterized by two types of spread, aerosol (airborne) and household contact.
The aerosol method of transmission of infection means its spread with the sputum or saliva of the patient - when sneezing, talking, breathing. Microscopic droplets of nasopharyngeal secretion in the form of an aerosol spread through the air. Inhalation or contact with the mucous membranes of the mouth, eyes and nose causes infection. A sick person poses the greatest danger in the first days, when the maximum number of active microparticles is released. In the first five to six days of illness, a person poses the greatest danger to others. In this case, factors such as closed spaces and poor ventilation play a negative role: when inhaling air saturated with viruses, the risk of infection for others increases.
In addition, the virus remains active on surfaces - plastic, fabric. This determines the possibility of contact and household infection. Effective methods of disinfection include heating, boiling, ozone, ultraviolet light and a number of chemical compounds.
Recovery from influenza in adults
After an influenza infection, most patients experience increased weakness, lethargy, and sleep disturbances for a long time. All these are manifestations of asthenic syndrome. As a rule, asthenia is expressed in increased exhaustion of mental and physical strength. The main symptoms in this case will be increased fatigue, tiredness and weakness.
After the disease, the patient often feels emotional instability, which is expressed in frequent mood swings and irritability. A feeling of anxiety, restlessness, and internal tension appears. The ability for prolonged mental and physical stress is lost. Autonomic disorders may also appear. Frequent headaches are a concern, sweating increases, appetite worsens, there is a feeling of interruptions in the functioning of the heart, memory deteriorates, and sleep is disturbed. Daytime sleepiness may occur.
With asthenic syndrome, it is necessary to take care of an organized work and rest schedule and minimize stress. It is necessary to adhere to a daily routine, do not forget about moderate physical activity, and try to spend more time in the fresh air. The diet must be balanced, contain the required amount of proteins, fats, carbohydrates, vitamins and microelements with the obligatory inclusion of fresh vegetables and fruits in the menu. On the recommendation of a doctor, you can take vitamin and mineral complexes.
Reference and information material
Author of the article
Gerasimenko Igor Olegovich
General doctor
- R.Z.Gatich, L.V. Kolobukhina, E.I. Isaeva, E.I. Burtseva, T.G. Orlova, F.V. Voronina, V.V. Malinovskaya “Efficacy of Viferon for influenza in adult patients”, Russian Medical Journal No. 14, 2004.
Sources:
https://cyberleninka.ru/ [ii]https://umedp.ru/ [iii] https://www.influenza.spb.ru/ [iv] https://ru.wikipedia.org/ [v] https://eduherald.ru/ [vi] https://rospotrebnadzor.ru/
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Routes of transmission and causes
The cause of influenza is damage to the body by type A viral strains.
The main sources of the infectious process are people, patients or carriers, as well as animals and birds.
Infection is carried out by air, the period from the penetration of the virus into the body until the appearance of the first signs is no more than 2 days. Therefore, the disease is characterized by a high degree of contagiousness.
Contributing factors to viral infection are a decrease in the immune system, close contact with sick people and the presence of concomitant pathologies.
People at risk for developing influenza A include:
- Women during pregnancy.
- Small children of preschool age.
- Health care workers.
- People exposed to frequent stress, having neoplasms, vitamin deficiencies, and following a strict diet.
