Chickenpox (chickenpox)

Incidence

In Russia

The incidence of chickenpox in Russia in 2020 decreased by 40.3% compared to 2019 - such data were published in the annual state report of Rospotrebnadzor "On the state of sanitary and epidemiological well-being of the population in the Russian Federation in 2020." However, windfall continues to be one of the leading economic losses among infectious diseases in the Russian Federation. At the same time, experts draw attention to the fact that a sharp decrease in the spread of chickenpox is associated with restrictive measures during the COVID-19 pandemic, when a number of measures were taken to prevent the spread of infection: a remote format of work and training was introduced, requirements were introduced to wear masks and other personal protective equipment, etc. All these measures became a barrier to not only coronavirus, but also other infections, including the causative agent of chickenpox.

The report notes that in 2020, compared to 2019, the volume of preventive immunization against chickenpox increased by 30%. However, immunization levels continue to be insufficient to significantly influence the epidemic process of the infection, not only in the country but also in individual regions.

The average long-term incidence in the Russian Federation is more than 560 people per 100,000 population, contagiosity - 0.75-0.90, the risk of carrying chickenpox during life in each person is 95%.

In the world

According to WHO, chickenpox is considered a relatively benign disease. However, according to 2021, about 4.2 million severe and complicated cases are recorded annually in the world, and 4200 are fatal.

Varicella Zoster virus - a causative agent of varicella

Main article: Viruses

Varicella Zoster virus, a causative agent of varicella, is dangerous due to its high contagion: it can move in the air for distances of up to 20 m, and the risk of infection for susceptible (that is, without immunity against varicella) individuals is 90%.

Varicella Zoster virus in 2020 was detected in 11 newborns in Russia. So there's a risk of congenital transmission.

Reactivation of Varicella Zoster virus after chickenpox - but already in the clinical form of herpes zoster - can be influenced by the pathogen COVID-19. Such cases were repeatedly recorded in 2020.

Possible complications in adulthood

The impact of "chickenpox" - a common childhood infection - on human health in adulthood is largely underestimated.

Often, after chickenpox, pneumonia, encephalitis, neurological disorders, vision loss and other complications develop, Irina Vladimirovna Fridman (St. Petersburg) told in 2021.

• 10-20% of patients who have suffered from chickenpox over the age of 50 may suffer from zoster; sometimes these conditions are accompanied by paralysis, visual impairment . In 2020, 15,168 cases were registered in Russia, and the incidence rate was 10.33 per 100,000 population. And 91% are adults.

• In 15%, neuralgia and pain syndrome persist for months and years.

According to a survey conducted at the initiative of the international health research company GSK in 2021, 43% of respondents are sure that the consequences of infection with varicella virus cannot appear in adulthood. One in five people think that the disease is mild and does not cause serious complications. In addition, the survey indicates a lack of awareness of Russians about preventive measures: more than half of respondents are not aware of the possibility of vaccinoprophylaxis^[1].

Meanwhile, windfall is dangerous primarily with its complications. These include pneumonia, meningitis, encephalitis, myocarditis, etc. In addition, a severe course and a complicated course of chickenpox are possible in initially healthy persons, and it is unfortunately impossible to predict the severity of the course of chickenpox before the development of symptoms.

And even if the disease proceeds in a mild form, the virus does not disappear, but forever remains in the body in a "dormant" state. When immunity is weakened, it can manifest itself already in adulthood in the form of herpes zoster, which is also known as zoster. A complication of herpes zoster is postherpetic neuralgia - one of the most intractable pain syndromes: severe pain can continue for months, causing painful suffering.

"Few people know that chickenpox can lead to severe complications. Windmill encephalitis, as well as common forms when rashes occur not only on the skin and mucous membranes, but also on internal organs, can be fatal. The risk group for severe forms of chickenpox includes children with severe chronic diseases, people with immunodeficiency, as well as newborns, especially if varicella infection occurs in utero, "says Elena Meskina, chief freelance child infectious disease specialist at the Ministry of Health of the Moscow Region

According to the candidate of medical sciences, the chief doctor of the multidisciplinary medical center in the Moscow region, pediatrician Yevgeny Timakov, chickenpox in some cases causes chickenpox encephalitis, heart lesions, purulent diseases, in 5-10% of children chickenpox occurs with complications, disability is possible.

"Chickenpox can occur in an atypical form, can give very serious complications, the most severe of them is chickenpox encephalitis, which can lead to the development of mental disorders, blindness, deafness and even death of the child. Also, do not forget that the varicella virus belongs to the class of viruses that cause chronic diseases, and for life remains in the dorsal ganglia of the spinal cord.<…> Vaccination against chickenpox protects against infection, and even if the child becomes ill, the disease will occur in a mild form, "said Alexander Gorelov, deputy director for scientific work at the Central Research Institute of Epidemiology of Rospotrebnadzor.

Vaccination

It is important to properly assess the current epidemic situation and minimize the risk of varicella infection. The main preventive measure aimed at protecting the population from chickenpox is immunoprophylaxis, which is aimed at creating immunity (immunity) to this infection.

Mass vaccine prophylaxis of varicella was first carried out in Japan back in 1996, it showed good results in terms of the formation of collective immunity. Since then, many countries have taken a similar path. Varicella vaccination is included in the national calendars of the United States, many countries in Europe. At the end of 2021, 43 countries of the world included varicella vaccinations in national calendars.

In the Russian Federation, immunization against this disease as of 2021 is included in the schedule of vaccinations according to epidemic indications. Effective protection against varicella after vaccination has been maintained for 14 years, and the proportion of cases of severe disease among vaccinated patients has decreased by 95%.

Economic losses

The incidence of chickenpox creates an additional burden on the state budget. The economic damage caused by this disease in 2020 amounted to more than 18 billion rubles.

The material is intended for a wide audience. The information provided in this material does not constitute or replace a doctor's consultation. For more information, contact a health professional.

Notes