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My close friends — a husband and wife. Live together.

Husband was ill coronavirus disease. Wife — no. Although no quarantine measures are not taken. Sleep, however, in the other room and eat from separate utensils. And everything else — as usual.

Coronavirus is characterized by high contagiousness, but for some reason she didn’t get sick.

it is not so rare. Chinese and South Korean scientists in March conducted a survey of clusters of human cases. The results showed that if one family member is sick, it is not the fact that after it gets sick the whole family.

In March, however, haven’t had antibody tests, so it was assumed that “not sick” family members, probably still ill but asymptomatic. However, before the may holidays was published a new study, now scientists at the University of Bonn. Judging by his results, not “sick” family members with the coronavirus do not ill. The contagion not one of them latched on. This was understandable because their antibody tests were negative. If they had, even without symptoms, antibodies had to be determined.

the statistical survey was conducted in the city of Gangelt (West Germany) from 31 March to 6 April. This small town with a population of 12.5 thousand people seemed to scientists an ideal model to study the spread of coronavirus because on 15 February there was held a street carnival. After it happened the explosion of the disease. February 28, the city authorities have introduced quarantine measures, curfews, allowing the spread of infection was stopped.

According to official figures in Gangelt ill 340 people (3% of the population), and died seven, almost 2% of the patients.

To find out how these numbers correspond to the true state of Affairs, the scientists of the University of Bonn collected data 1007 of the citizens living in 405 households (one household — one family).

each of the 1007 citizens took swabs and coronavirus antibody tests. Everyone who was sick and was treated with the involvement of official medicine, put his medical history. In addition, all were asked to fill out forms to indicate the gender, age, participation in the carnival March 15, chronic diseases, the day when ill СОVID, if you are sick, what were the symptoms and course of the disease.

the Main task, pursued by scientists of the University of Bonn, to determine the index of deaths from coronavirus infection. To do this, they first had to figure out how many people fell ill, including ill easy, medium, hard and without any symptoms.

According to the survey the total number of cases was five times higher than the official figures: 15%, not 3%. The corresponding��but, the index of mortality in Gangelt does not look so intimidating: died in the city of 0.37% of the total number of cases.

Scientists found no relationship between the chance of being infected, gender, age and presence of chronic diseases.

But they saw a direct link between the severity of the disease and participation in a mass event — a street carnival. Sick of carnavalesca was three times more than those who became ill without the carnival. In addition, carnival worker was sick more serious. For intrafamilial infection Gangelt demonstrated even more surprising numbers.

the researchers analyzed the risk of Contracting for a family member in which you are already sick of one person.

Theoretically, this risk is very high. After all, live in the same house or apartment, breathing the same air. But according to the calculations performed on the basis of data collected in Gangelt, this risk was significantly below 100%.

In families where two people and one is sick, second the probability to be ill 43,59%. In families with three members the chances of Contracting the second and third 35,71%.

for families with four members — second, third and fourth family members get sick with a probability of 18,33%.

However, if the first in the family of a sick child under 18 years of age, in adults, the risk increases.

If the family has only three people, the chances of parents of a sick child to pick up from him COVID rise to of 66.67%. But if family members are four, then they will become infected from your baby is less likely — all of 33.33%.

“the Reason for the relatively low risk of infection among family members is unknown — say German scientists. But the same phenomenon is observed with other respiratory diseases such as H1N1 influenza or SARS. Perhaps, in those families where one is sick, other family members quickly acquire some level of immunity (e.g., T-cell immunity), which is not determined by tests for antibodies, but is able to protect them from being infected.”

Instead of catching something from a sick relative or cohabitant of respiratory infection, some family members seem to be “infected” with the immunity to it. But as it happens, however, what mechanisms work and why they work, not all, scientists do not yet know.