Epidemiology of measles

Measles in the pre-vaccination period was the most common infection in the world and was found everywhere. The incidence of morbidity every 2 years is explained by the accumulation of a sufficient number of people susceptible to measles. The incidence of measles was observed all year round with a rise in autumn, winter and spring.

The source of infection is only a sick person. The most infectious patient in the catarrhal period and the first day of the appearance of the rash. From the third day of rashes, the contagiosity decreases sharply, and after the 4th day the patient is considered to be non-contagious.

Transmission of the infection occurs by airborne droplets. When coughing, sneezing with droplets of mucus from the upper respiratory tract, the measles virus is released into the external environment and the current of air in enclosed spaces can spread to significant distances - to neighboring rooms and even through corridors and staircases to other apartments. It is possible to bring the measles virus from the lower to the upper floor through the ventilation and heating system. Transmission through a third party is a rarity, as the measles virus outside the human body quickly dies.

The contagious index is 95-96%. When dribbling measles in places where there have been no measles epidemics for a long time and vaccination has not been carried out, almost the entire population is ill, as susceptibility to the pathogen persists to a very old age.

After measles, a persistent immunity is created, repeated diseases are rarely observed. In the pre-vaccination period, almost 90% of people had measles already under the age of 10 years. Children who are aged from 1 to 4-5 years are more often infected with measles, and rarely get measles up to 6 months. Children under 3 months, as a rule, do not get measles, which is explained by passive immunity received from the mother. After 3 months, passive immunity decreases sharply, and after 9 months disappears in all children. If the mother did not have measles, the child can get it from the first day of life. Perhaps intrauterine infection, if the mother is ill with measles during pregnancy. In recent years, in connection with the mass immunization of children against measles, adults who have not previously been vaccinated or who have lost immunity are more likely to suffer.

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