Prevention of influenza vaccination. Modern tactics of influenza vaccine prevention

Modern tactics of influenza vaccine prevention

A.V. Loginov.
Representative office of "Pasteur Merier Connaught" in the CIS

Currently, there are two approaches to preventing influenza in the world: immunoprophylaxis with an inactivated vaccine and chemoprophylaxis with antiviral drugs (such as amantadine or rimantadine).

Annual vaccination of persons at high risk of influenza complications is the most effective preventive measure. International experience shows that when using inactivated vaccines, it is not necessary to take a break from influenza vaccination every three years. The vaccine is most cost-effective when vaccinating people who are susceptible to complications or who are at increased risk of transmitting the virus. It is obvious that it would be advisable to get vaccinated during hospitalization or one of your routine doctor's visits before the onset of influenza season.
Inactivated influenza vaccines contain three strains of the virus (usually two type A and one type B) that are likely to circulate around the world during the next flu season. So, for the 1998-1999 season. they contain influenza virus H1N1, H3N2 and B (strains: A/Beijing/262/95-like, A/Sydney/5/97-like and B/Beijing/184/93-like). Instead of B/Beijing/184/93, manufacturers use an antigenically identical strain - B/Harbin/07/94 due to better technological characteristics. Since the composition of the vaccines for the 1998-1999 season. differs from the composition of the vaccines of the 1997-1998 season, the vaccine stocks of the 1997-1998 season. should not be used to prevent influenza during the 1998-1999 season.

Groups to be vaccinated
Dosage recommendations vary by age group (see table). Two doses of the vaccine, given at least one month apart, are required to achieve a significant antibody response in children under 9 years of age who have not been previously vaccinated.

Table. Dosage of influenza vaccines depending on age.

Groups at high risk of developing influenza complications

Adults and children with chronic pathologies of the respiratory and cardiovascular systems, including children with bronchial asthma.
Adults and children who required regular medical observation or hospitalization for a year because of chronic metabolic diseases (including diabetes mellitus), renal dysfunction, hemoglobinopathy, or immunosuppression (including drug-induced immunosuppression).
People of any age who have a chronic condition and are in long-term care facilities.
Children and adolescents (ages 6 months to 18 years) who are receiving long-term aspirin therapy due to the risk of developing Reye's syndrome with influenza.
Women who are in the 2nd or 3rd trimester of pregnancy during a seasonal epidemic rise in incidence.
Persons over 65 years of age.

Groups of people at increased risk of influenza virus transmission
People with influenza can spread the disease to those in high-risk groups they care for or live with. In this regard, the following should be vaccinated:

Doctors, nurses and other staff in both hospitals and other health care settings
Employees of special institutions for the care of patients with chronic pathologies who are in contact with the contingent of these institutions.
Family members of patients at risk

Vaccination of other population groups
Breastfeeding mothers can get vaccinated because the influenza vaccine does not affect the safety of breastfeeding for mothers and children. Lactation does not affect the immune response and is not a contraindication to vaccination.

Vaccine prevention of influenza can be carried out for people who want to reduce the risk of the disease (the vaccine can be prescribed to children from 6 months of age). Persons whose activities are particularly important should be considered candidates for vaccination to minimize the risk of interruption of socially important activities during epidemics.

Concomitant use with other vaccines
The flu vaccine can be given at the same time as other routine vaccinations.

Flu vaccination time
The optimal time for a vaccination campaign for high-risk individuals is usually between October and mid-November. For children under 9 years of age, the second dose should be given before December if possible. Vaccination with inactivated vaccines to prevent influenza is not contraindicated during the annual epidemic rise in incidence.

General contraindications
Inactivated influenza vaccines should not be administered to persons with hypersensitivity to egg white or other components of influenza vaccines without first consulting a physician. However, individuals with hypersensitivity who are at risk may be vaccinated with appropriate assessment of the degree of allergy and desensitization.
Persons with acute febrile illness should not usually be vaccinated until symptoms resolve. Mild illness with or without fever should not be a contraindication to the use of influenza vaccines.

Bibliography

Prevention and control of influenza. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR, CDC, V.46, No. RR-9.
1997 Red Book: Report of the Committee on Infectious Diseases. 24th ed. Elk Grove Village, IL: American Academy of Pediatrics, 1997, pp. 307-315.
Order of the Ministry of Health of the Russian Federation No. 25 of January 27, 1998 “On strengthening measures to prevent influenza and other acute respiratory viral infections”

Almost every person has had the flu at least once in their life. Influenza is a serious infectious disease that is characterized by severe intoxication, moderate catarrhal symptoms, and damage to the trachea and large bronchi. The causative agent of influenza is a virus that multiplies in the mucous membrane of the respiratory tract.

Reasons for the high incidence of ARVI and influenza:

The rise in the incidence of influenza begins in the cold season. On the one hand, this is facilitated by the high resistance of the influenza virus to low temperatures. On the other hand, hypothermia reduces the protective properties of the human body.

The source of infection is a sick person. The route of spread is airborne. This explains such a rapid spread of the virus within the premises, in organized groups.

COURSE OF THE DISEASE

Fulminant flu

Primary viral pneumonia is the most severe form of influenza. This form is most characteristic of pandemics and affects people regardless of their age and health status.

The disease begins with typical symptoms of the flu, but after 3 days the temperature rises rapidly, cough, shortness of breath and cyanosis appear. Pulmonary edema develops, followed by heart failure and complications from the kidneys and nervous system. Death occurs very quickly and with high frequency. The use of antibiotics is useless. During the pandemic of 1918-1919. (“Spanish flu”), when 20 million people died, the fulminant form most often affected young, healthy adults.

Typical flu

An acute respiratory infectious disease with a sudden onset after an incubation period of 1-2 days, accompanied by fever, weakness and other symptoms of intoxication, as well as damage to the respiratory tract.

The period of infectivity lasts 3 days from the onset of clinical symptoms (durations of up to 5 days have been described).

The most important symptom is an increase in body temperature. The temperature quickly rises to 40-41°C, parallel to the development of other general symptoms. The febrile period usually lasts 3 days, sometimes 4-8 days. Recovery is quick, but weakness and asthenia may persist for several days, and some patients may develop serious complications.

Complications

The most common manifestation of superinfection with influenza is secondary bacterial pneumonia. It is from this that most young children, elderly people and patients with chronic diseases die.

Pneumonia develops 4-14 days after flu symptoms disappear. Viral infection protects the lungs' defense system. This creates conditions for the proliferation of microorganisms such as Streptococcus pneumoniae, Staphylococcus aureus and other bacterial flora.

In addition to pneumonia, there are other respiratory complications: croup (laryngotracheobronchitis), otitis media, etc. (sinusitis, rhinitis).

Flu can also provoke an exacerbation of chronic lung diseases (asthma, bronchitis); decompensation of cardiovascular diseases (myocarditis, pericarditis), renal failure or endocrine disorders (diabetes mellitus).

VACCINATION

Flu vaccination recommended for all persons 6 months and older who are at risk due to age or health condition. Vaccination is also required for healthcare workers and family members who come into contact with patients at risk. In addition, vaccination is recommended for all people who want to reduce the likelihood of contracting the flu.

Risk groups for complications due to influenza: elderly people suffering from chronic somatic diseases, often suffering from acute respiratory infections, preschool children.

Groups at high risk of infection: medical personnel, workers in the service sector, transport, educational institutions, military contingents, schoolchildren, etc.

Groups at high risk of influenza virus transmission: medical and other personnel of medical institutions, including ambulance and emergency care; long-term care facility staff in contact with patients; caregivers of high-risk patients, including family members.

Prevention of influenza is annual vaccination.

Do I need to be vaccinated annually??

The anti-flu immunity that developed last year will not save you from the flu this year. Due to the continuous variability of influenza viruses, a completely new flu appears every fall, from which last year's vaccinations do not help. Therefore, new vaccinations must be done every year. If you are vaccinated with last year's vaccines, the effectiveness of vaccination decreases to 20-40%, instead of 70-90%.

There are several reasons for annual vaccination:

Virus variability (emergence of new subtypes or annual antigenic drift). In this regard, the strain composition of vaccines changes annually.
The duration of immunity (antibody circulation) caused by both vaccination and natural infection is about a year (especially in the elderly).

The effectiveness of vaccination in preventing complications and mortality.

A 48-75% reduction in the frequency of hospitalizations for influenza and pneumonia.

In children aged 6-30 months: 69% effectiveness in preventing acute otitis media (AOM).

In children with pathology: among children with asthma, the effectiveness of attack prevention is 67.5%.

The best way to fight the flu is to prevent it. It includes:

isolation of patients, the use of personal protective equipment (gauze masks on the face) are effective, but in fact it is difficult to strictly adhere to this regime;

flu shots - vaccination(every year, flu vaccines are produced taking into account the expected strain of the virus) - a very high level of reliability of prevention;

Vaccination of the population is the most effective, a reliable and affordable means of preventing influenza; at the same time, the incidence rate and the risk of developing severe complications are significantly reduced, and mild forms of the disease predominate. All domestic vaccines are adapted for the upcoming season.

During the vaccination process, a particle of an infectious agent is introduced into the body (this can be a weakened or killed pathogen, or parts of it). The virus contained in the vaccine cannot cause disease, but it can stimulate the body to produce antibodies. Therefore, when a “wild” strain of the virus enters the body, it does not take time to develop antibodies - they are already there after vaccination. Antibodies bind to the virus and thus prevent the cell from becoming infected and the virus from multiplying. Thanks to this, the disease is prevented even before it begins.

The optimal time for vaccination against influenza is the autumn period - from September to November. This is explained by a number of considerations: influenza epidemics usually occur between November and March; antibody production takes about 2-4 weeks; the high titer of antibodies caused by vaccination lasts for several months and begins to fall 6 months after vaccination. Therefore, vaccination too early is not recommended (antibody titers may drop by the time the epidemic begins). If for some reason the vaccination was not done on time, then it can be done after the start of the flu epidemic. There is a widespread misconception that vaccination is contraindicated after the outbreak of an epidemic. This has to do with live influenza vaccines. Inactivated vaccines are recommended for use throughout the epidemic. However, if the vaccine was given when the person was already infected with the influenza virus (but clinical manifestations had not yet begun), then the vaccine may not be effective. Immunity resulting from influenza vaccination lasts 6 to 12 months, although protective antibody titers are detectable over a longer period of time. In general, a person vaccinated with an inactivated influenza virus can be considered to remain immune to influenza for up to 12 months.

And vaccination, as the most effective method of vaccine prevention, can significantly reduce the risk of influenza and all the ensuing consequences.

Vaccine prevention of influenza and ARVI

Influenza vaccination is included in the National Preventive Vaccination Calendar. Its importance in the prevention of acute respiratory viral infections, indications, contraindications and typical vaccine reactions should be known to preschool medical workers.

Epidemiology of ARVI

Clinical picture of influenza

Complications of influenza

Threat of pandemic influenza

Vaccine prevention of influenza

Flu vaccines registered in the Russian Federation

Flu prevention

Acute respiratory viral diseases (hereinafter referred to as ARVI) are the most common infection. ARVI pathogens often cause illness in preschool children, with children being the main spreaders of the infection.

Viruses that cause SARS are not endemic to any region or country and are distributed throughout the world. More often they cause epidemics in winter, but outbreaks are observed in spring and autumn, and sporadic cases of ARVI occur all year round.

To date, there are over 140 different viruses that cause acute respiratory viral infections, causing similar symptoms in the form of intoxication (fever and chills, headache, general malaise, loss of appetite), as well as damage to the respiratory system, such as rhinitis, pharyngitis, tonsillitis, laryngotracheitis, bronchitis, sometimes conjunctivitis. These diseases can cause serious complications such as bacterial sinusitis, otitis media and pneumonia. The most common pathogens of ARVI are influenza viruses, parainfluenza, rhinoviruses, adenoviruses, enteroviruses, respiratory syncytial virus, etc.

Epidemiology of ARVI

Only humans are the reservoir for ARVI pathogens, but in some cases infection can lead to asymptomatic infection; adenoviruses can be latently present in the tonsils and adenoids. The main mechanism of transmission of ARVI is airborne. Viruses are transmitted by microdroplets of saliva, which can spread over a distance of more than 5 m when coughing, especially when sneezing. The pathogen can also be transmitted by shaking hands, using contaminated utensils and other objects. Enteroviruses and adenoviruses that cause acute respiratory viral infections can be spread through the fecal-oral route. Infection caused by adenovirus types 3, 4 and 7 can be transmitted by swimming in indoor pools.

The incubation period after infection with viruses that cause ARVI lasts from 1 to 10 days, usually 3–5 days. The infectious period of a sick child ranges from 3 to 5–7 days. However, in the case of respiratory syncytial virus infection in children, it can be shed after the onset of clinical symptoms, although rarely for several weeks.

Post-infectious immunity is provided by virus-specific antibodies, but the protective antibody titer lasts for a relatively short time. Therefore, annual reinfection with influenza viruses, parainfluenza, respiratory syncytial virus and rhinoviruses is possible.

Clinical picture of influenza

Influenza in children is especially severe, because in preschool age the child first encounters this virus. The disease in a non-immune organism often occurs in a hypertoxic form with the phenomena of so-called influenza encephalopathy, hemorrhagic pulmonary edema - the main causes of death in influenza infection.

Due to the high epidemiological and clinical danger of influenza, its diagnosis in a child is carried out as early as possible. Currently, there are anti-influenza drugs, the timely use of which will help to avoid severe complications, especially in weakened children suffering from chronic somatic diseases.

The main differences between the flu clinic and other acute respiratory viral infections are shown in the table.

Clinical symptoms of influenza and ARVI

Symptoms

Start

Gradual

Always spicy. Patients, as a rule, can name the hour when they felt sick

Fever

The temperature rises slightly, rarely above 38.5 °C

The temperature reaches maximum values (39–40 °C and above) within several hours. High fever lasts 3–4 days

Symptoms of intoxication

Intoxication is mild, the general condition is usually satisfactory

Symptoms of intoxication quickly increase: chills, profuse sweating, severe headache in the frontotemporal region, pain when moving the eyeballs, photophobia, dizziness, aches in muscles and joints

Runny nose and nasal congestion

Frequent symptom, sometimes predominant

Usually there is no severe runny nose, only slight congestion is typical

Nose, which appears by the second day of illness

Catarrhal symptoms (sore throat, redness)

A common symptom that almost always accompanies a cold

In the first days of the disease, it is not always detected; the posterior wall of the pharynx and soft palate are usually hyperemic

Cough, chest discomfort

Weak or moderate, often hacking, dry cough, which appears from the onset of the disease

On the 2nd day of the disease, a painful cough often occurs, pain behind the sternum along the trachea, resulting from damage to the tracheal mucosa

Sneezing

Common symptom

Happens rarely

Conjunctival hyperemia (redness of the mucous membrane of the eyes)

It happens rarely, more often when there is a layer of bacterial infection

Quite a common symptom

Asthenic syndrome

After recovery it is expressed slightly

Fatigue, weakness, headache, irritability, insomnia may persist for 2–3 weeks

Complications of influenza

Typical complications of influenza:

– the most common are rhinitis, pharyngitis, laryngitis, tracheitis, bronchitis, bronchiolitis;

– sinusitis and pneumonia (viral and bacterial) lead to hospitalization and mortality; exacerbation of chronic diseases of the heart, lungs, kidneys due to infection;

– otitis media and gastrointestinal disorders such as nausea, vomiting, and sometimes diarrhea are less common.

During the epidemic season, the danger of ARVI is due to numerous complications, the total number of which reaches 20–30%, especially against the background of influenza infection, including due to mixed infections (influenza A/H3N2 and A/H1N1 viruses; A+B viruses ; influenza and parainfluenza viruses). Mixed infections are much more severe and longer than monoinfections, with complications, especially in young children.

A serious, although rare, complication of influenza, especially during influenza B epidemics, is Reye's syndrome with dysfunction of the central nervous system and liver, which most often occurs in children taking salicylates.

Threat of pandemic influenza

As already noted, only humans are the reservoir for the influenza virus. However, there are 12 serotypes of influenza A virus that cause influenza in animals (pigs, horses, chickens, ducks, etc.). Over the past decade, outbreaks of avian influenza and swine influenza in humans have become more frequent.

Outbreaks of bird flu were recorded in 1997–1999. (H9N2 virus) and in 2003–2004. (H7N7 and H5N1 viruses). At the same time, humans are most likely the final link in the transmission of the influenza virus (you can get sick as a result of contact with live infected poultry or consumption of raw infected meat), since there are still no cases of reliable transmission of this virus from person to person. Bird flu mainly affected children, in whom the disease often resulted in death.

The name “swine flu” has spread widely in the world media since the spring of 2009. At this time, it was found that in Mexico, a strain of influenza subtype A/H1N1, called “California 04/2009”, capable of causing disease in pigs, acquired the ability to be transmitted not only from animal to animal and from pig to man, but also from person to person. Due to massive transmission within the human population, the World Health Organization declared an influenza pandemic on June 9, 2009. Although this is a new strain, the H1N1 subtype has been circulating for a very long time, and most mature and older adults are at least partially immune to the new pathogen. Children and young people are predominantly affected by the H1N1 influenza virus.

The danger of a pandemic is possible if a new influenza virus appears that has antigens of an avian or swine and human virus. Such a virus can arise if pigs are simultaneously infected with more than one virus (avian, swine and seasonal human), which allows the genes of these viruses to mix. This may contribute to the emergence of an influenza virus containing genes from different sources, to which there will be no immunity in the human population. An important condition for the spread of infection in this case should be the ability of the new virus to be transmitted from person to person.

Vaccine prevention of influenza

Vaccination against influenza not only helps protect against influenza, but also reduces the incidence of ARVI, the incidence of acute otitis media and the number of hospitalizations during the epidemic season.

Due to the high variability of the antigenic specificity of influenza viruses, it is necessary to vaccinate annually with vaccines containing current antigenic variants of the influenza virus. Effective influenza vaccines protect 80–100% of vaccinated healthy people and 50–60% of people with chronic diseases from influenza disease.

For vaccine prevention of influenza, live and inactivated vaccines are used, the latter are divided into:

to whole virion (not used in children);

subunit, containing only the surface antigens hemagglutinin (H) and neuraminidase (N) isolated from the virion;

fragmented from a destroyed virus - split vaccines.

Inactivated vaccines do not contain live viruses and cannot cause influenza. Vaccination is carried out in the autumn, when respiratory diseases are most common. Therefore, a child may get sick after vaccination - this is a coincidence and has nothing to do with the vaccine.

Subunit vaccines include only the surface proteins of the virus and, unlike split vaccines, do not contain internal viral proteins. Therefore, adverse reactions when using subunit vaccines are much less common than when using split vaccines.

Many years of clinical experience with the use of inactivated vaccines allows us to conclude that they have proven themselves to be safe vaccines.

Adverse reactions when using inactivated vaccines

Adverse reactions may occur as a result of using inactivated vaccines.

Local reactions occur most often in the form of redness (erythema), pain and, less commonly, swelling at the injection site. These short-term effects usually resolve within 1–2 days.

Nonspecific systemic reactions are characterized by fever, chills, malaise and myalgia. They are more often observed when the vaccine recipient has not had previous contact with the viral antigen present in the vaccine. They usually occur 6–12 hours after vaccination and last no more than 1–2 days.

Contraindications to flu vaccination

– acute illness or exacerbation of a chronic disease on the day of vaccination;

– allergy to chicken egg whites;

– allergic reactions to other components of the drug;

– severe allergic reactions to a previous vaccination with this drug.

Hypersensitivity is an extremely rare reaction that is believed to be allergic in nature. Most often occurs in people with an allergy to chicken protein, since the vaccine contains trace amounts of this protein. Persons who have previously had reactions to chicken eggs such as hives, swelling of the lips and tongue, difficulty breathing or collapse should consult a doctor before consuming the vaccine. Also, consultation with a doctor is necessary if allergic reactions have been noted to previous injections of the vaccine.

Vaccine prevention for other respiratory viruses has not been developed. However, there is evidence of the effectiveness of the use of immunocorrective drugs in children, especially those who are often and long-term ill, for the prevention and reduction of the frequency of acute respiratory viral infections and acute respiratory infections in general*.

Frequently ill children and children with chronic ENT pathology need not only vaccination against influenza, but also vaccination against Haemophilus influenzae and pneumococci. Such a combined vaccination can significantly reduce the frequency of acute respiratory diseases, exacerbations of diseases of the ENT organs and helps reduce adenoid vegetations.

G.B. Rogova,

consultant of the information center "MCFER Educational Resources"

Despite the significant contribution of vaccination to reducing the incidence of influenza, the prevalence of this infection remains extremely widespread. Influenza is the leading cause of visits to medical care for acute respiratory infections, causing up to 300 thousand hospitalizations and leading to 20-40 thousand deaths annually.

Changes and additions made by the Advisory Committee on Immunization Practices (ACIP) in 2006.

Incidence and mortality from influenza

Children, elderly people and people suffering from chronic concomitant pathologies are at the highest risk of infection, complications and adverse outcomes of infection. All of the above emphasizes the importance of timely prevention and treatment of infection. Prevention of influenza comes down to routine measures, the use of vaccines and antiviral drugs.

General approaches to creating vaccines

Seasonal influenza epidemics are caused by two types of virus - A and B, while type C causes sporadic infections. Influenza viruses types A and B constantly undergo changes in their surface antigens - hemagglutinin (H) and neuraminidase (N), which is regarded as an evolutionary adaptability and makes it difficult for them to be recognized and eliminated by the human immune system. There are two mechanisms of antigenic variability:

antigenic drift, leading to relatively small changes;
antigenic shift, leading to pronounced changes (occurs every 10-40 years).

The high variability of the influenza virus requires the regular development of new vaccines. Every year, under the auspices of WHO, virus strains are identified that are most likely to circulate in the coming season, and vaccines based on them are developed, taking into account antigenic variability. The vaccine contains 3 types of viral antigens - 2 types A and 1 type B. The process of developing and releasing vaccines takes about 6 months and is problematic for many reasons (complexity of the development process, production time, potential bacterial contamination of chicken embryos on which cultivation is carried out viruses, etc.).

Trivalent influenza vaccines. Types of Vaccines

The trivalent inactivated whole virion vaccine was introduced into clinical practice back in the 50s of the last century and contained killed whole viral particles. Currently, a trivalent subunit vaccine is used, consisting of purified subunits of the neuraminidase and hemagglutinin antigens of the virus.

Antibodies produced during intramuscular injection of the vaccine suppress viral replication, but do not provide adequate secretory immunity to minimize the risk of infection. It has been proven that the protective reaction after vaccine administration is directly proportional to the degree of the recipient’s immune response, however, in elderly people this dependence is not always detected. It must also be taken into account that the vaccine is effective only against virus strains with similar H and N antigens contained in it.

Current vaccines are highly purified, do not contain live virus particles, and cannot cause influenza infection. However, in people with a hyperreactive immune system (allergy sufferers) and children, increased levels of cytokines in the blood after vaccination may cause flu-like symptoms. Such undesirable reactions that develop after their administration occur relatively rarely and, as a rule, are mild in nature.

General approach to vaccination

The optimal time for vaccination is from October to November before the seasonal peak of incidence. At the same time, vaccine prevention is advisable throughout the entire epidemic season, since the concentrations of anti-influenza antibodies reach protective levels several weeks after the vaccine is administered, and the epidemic season can last much longer.

The vaccine is administered annually in a single dose of 0.5 ml into the deltoid muscle in adults and children over 3 years of age. For children aged 6 to 35 months, the vaccine is prescribed in a dose of 0.25 ml intramuscularly into the anterolateral thigh. Vaccination against influenza can be carried out simultaneously with the use of other vaccines (for example, pneumococcal conjugate), provided that they are administered to different anatomical areas with different syringes.

Efficiency

If the viruses contained in the vaccine match the circulating epidemic strains, the reduction in hospitalization and mortality from influenza with its use reaches 70-90% in relatively healthy adults, as well as in children and adolescents.

The analysis of the feasibility of the costs of vaccination of the adult population confirmed its positive economic effect in people aged 18-50 years. In a placebo-controlled study involving 849 healthy people aged 18-64 years, it was found that the administration of the trivalent influenza vaccine was accompanied by a reduction in the frequency of visits to the doctor for upper respiratory tract infections by 25%, and the number of days of disability by 43 % and costs – by $46.85 per vaccinated person.

In elderly people, vaccine prevention led to a reduction in the frequency of hospitalization for influenza by 50-60%, and mortality by 80%. In this case, its lower effectiveness is probably due to chronic concomitant pathology and age-related changes in the immune system. However, according to research results, vaccination of this population is clinically and economically justified. Please remember that the flu vaccine does not protect against other respiratory infections.

Safety

It has previously been suggested that annual administration of the vaccine may become addictive over time and lead to a decrease in protective immunity, but studies have not confirmed this hypothesis. There was also no significant association between the use of the trivalent vaccine and the development of Guillain-Barré syndrome (acute demyelinating polyneuropathy) (incidence ≤1 per 1 million vaccinated). However, previous Guillain-Barre syndrome is a contraindication for vaccination.

In a number of cases, the development of allergic reactions of the anaphylactic type to chicken proteins and the preservative thimerosal has been noted, however, the administration of vaccines to allergy sufferers is considered possible after specific desensitization.

Not all influenza vaccines can be used during pregnancy. At the same time, the trivalent inactivated vaccine is recommended for use in pregnant women, as well as women planning pregnancy, due to the high morbidity and mortality from influenza in this category of people.

The purpose of vaccination is to prevent seasonal influenza epidemics. Indications for vaccination are:

In adults:
1. medical:
  - chronic diseases of the cardiovascular and respiratory systems (bronchial asthma, etc.);
  - chronic diseases accompanied by metabolic disorders (diabetes mellitus, renal failure, hemoglobinopathies, etc.);
  - immunodeficiency states of various origins (taking immunosuppressants, HIV infection, etc.);
  - any conditions leading to difficulty breathing, impaired secretion from the respiratory tract and increasing the risk of aspiration (cognitive impairment; spinal cord damage; diseases accompanied by convulsive syndrome; neuromuscular diseases);
  - pregnancy during the epidemic season;
2. social:
  - healthcare workers, staff and residents of nursing homes, etc.;
  - persons in contact with people who belong to risk groups, including children under 5 months of age;
3. optional.
In children:
- children aged ≥6 months with diseases of the respiratory and cardiovascular systems, sickle cell anemia, diabetes mellitus, diseases leading to difficulty breathing, impaired secretion from the respiratory tract and increasing the risk of aspiration, as well as HIV-infected people;
- healthy children aged 6 to 23 months, as they have a significantly increased risk of developing an infection requiring hospitalization.

Vaccination of health workers

The frequency of vaccination of medical personnel against influenza is still not high enough. At the same time, during the epidemic season, medical workers often come into contact with patients with influenza in the acute phase, which significantly increases the risk of their infection with subsequent transmission of infection to other patients and, in turn, leads to an increase in the length of stay of patients in the hospital, an increase in the frequency of exacerbation of concomitant diseases and mortality.

Currently, vaccination of doctors is considered as one of the aspects of improving the safety and quality of medical care.

Seasonal Influenza: Prevention With Influenza Vaccines. Medscape

Influenza vaccination: changes and additions made by the Advisory Committee on Immunization Practices (ACIP) in 2006.

In 2006, the Advisory Committee on Immunization Practices (ACIP) made the following changes to previous influenza vaccination recommendations.

Healthy children aged 24 to 59 months and those living with and caring for them are recommended to be vaccinated unless there are contraindications.
All children aged 6 months to 9 years who have not previously been vaccinated are recommended to receive 2 doses of the vaccine (when using a trivalent vaccine, the interval between doses is 4 weeks).
Manufacturers should develop programs to increase vaccination coverage.
Vaccination should be carried out throughout the epidemic season, and not just at the beginning or before its onset.
Amantadine and rimantadine should not be used for the prevention or treatment of influenza, given the high level of viral resistance to these drugs.
Trivalent vaccine in the 2006-2007 epidemic season. includes A/New Caledonia/20/1999 (H1N1)-like, A/Wisconsin/67/2005 (H3N2)-like and B/Malaysia/2506/2004-like antigens.

The issue of introducing total vaccination against influenza in the absence of contraindications is also being considered.

Prevention and Control of Influenza Recommendations of the Advisory Committee on Immunization Practices (ACIP). CDC, MMWR 2006; 55 (RR10): 1-42

Flu vaccines are updated annually. Vaccination is carried out with vaccines created against viruses that circulated in the previous winter, so its effectiveness depends on how close those viruses are to the present ones. However, it is known that with repeated vaccinations the effectiveness increases. This is due to the fact that the formation of antibodies - protective antiviral proteins - occurs faster in previously vaccinated people.

What vaccines exist?

Currently, 3 types of vaccines have been developed:

Whole-virion vaccines are vaccines that are a whole influenza virus, either live or inactivated. Now these vaccines are practically not used, since they have a number of side effects and often cause disease.

Split vaccines are split vaccines containing only part of the virus. They have significantly fewer side effects and are recommended for vaccination of adults.

Subunit vaccines are highly purified vaccines that cause virtually no side effects. Can be used in children.

When is the best time to get vaccinated?

It is best to vaccinate in advance, before the epidemic develops - from September to December. It is also possible to get vaccinated during an epidemic, but you must keep in mind that immunity is formed within 7-15 days, during which it is best to carry out additional prophylaxis with antiviral agents - for example, rimantadine.

Vaccine safety:

As already mentioned, for greater safety it is better to use the most purified subunit vaccines.

Adverse reactions:

Local reactions in the form of redness, disappear in 1-2 days

General reactions: fever, malaise, chills, muscle pain. They occur quite rarely and also disappear within 1-2 days

Allergy to vaccine components. It is important to remember that the vaccine should not be administered to people with chicken protein intolerance, since the viruses used in vaccines are grown using this protein, and the vaccines contain traces of it. If you are allergic to influenza vaccines, subsequent vaccinations cannot be performed.

Emergency prevention of influenza

In the event of an outbreak of the disease in a closed community or during a flu epidemic, the effectiveness of vaccination is significantly reduced, since it takes at least 1-2 weeks to form full immunity.

Therefore, if vaccination has not been carried out, especially in people at risk, prophylactic use of antiviral drugs is advisable.

Rimantadine is taken daily at the same time at a dose of 50 mg for no more than 30 days.

Oseltamivir (Tamiflu) is also effective at a dose of 75 mg 2 times a day for 6 weeks.

For emergency prevention, specific anti-influenza immunoglobulin can also be used, especially in patients with immunodeficiency

Viral complications of influenza

Primary viral pneumonia is a rare but extremely serious complication of influenza. Caused by the spread of the virus from the upper respiratory tract further along the bronchial tree and damage to the lungs. The disease begins like the flu and progresses steadily. Intoxication is expressed to an extreme degree, shortness of breath is observed, sometimes with the development of respiratory failure. There is a cough with scanty sputum, sometimes mixed with blood. Heart defects, especially mitral stenosis, predispose to viral pneumonia.

Infectious-toxic shock – extreme degree of intoxication with impaired functioning of vital organs: in particular the cardiovascular system (a pronounced increase in heart rate and a critical drop in blood pressure is observed) and kidneys. The first manifestation of infectious-toxic shock.

Myocarditis and pericarditis – How complications of influenza occurred during the Spanish flu pandemic. Currently they are extremely rare.