How, where and under what conditions is Covid-19 spread? Immunologist Viola explains a study in science

How, where and under what conditions is Covid-19 spread? Recent research sheds new light on the subject. “Through follow-up investigations in Hunan, China, the researchers were able to analyze how SARS-CoV-2 transmission occurs,” writes immunologist Antonella Viola on Facebook at the opening of a post in which she summarizes the main results of A study. epidemiological just published in the prestigious journal Science.

“The risk of virus transmission depends on how close the social interactions are: the risk is low in community interactions (restaurants, entertainment and transportation), intermediate for social events (friends and family who do not live together) and maximum in the same All this confirms that the transmission of SARS-CoV-2 is facilitated by proximity, closed environments and the high frequency of contacts “, writes the scientist.

“The study also suggests that restrictive measures have different impacts in various contagion situations, effectively changing and confining transmission within family contacts,” Viola continues, explaining: “The researchers also suggest that restrictive measures should be designed on the basis of of the community’s tracking and diagnostic capabilities. This means that, in addition to the number of infections, in order to decide what measures to adopt, it is necessary to evaluate the effectiveness of the tracking system and the possibility of testing in the territory. “

The immunologist continues to emphasize that a “very interesting fact” is represented by the fact that “63% of transmission events are caused by presymptomatic people. This greatly complicates things from the point of view of managing the epidemic because if we isolate people who are already symptomatic, we are acting too late. Instead, we should try to identify infections very early, through intense follow-up activity, to act in presymptomatic and asymptomatic patients ”.

Then we turn to the data on susceptibility to infection (risk of becoming infected): “It seems clear that children (0-12 years) have a lower risk of becoming infected (compared to the age group 26-64 years) . Also, people over the age of 65 have a higher risk of getting the infection. This means that with age, not only the susceptibility to disease (more serious disease) increases, but also to infection ”, adds Viola.

“Regarding infectivity (the probability of spreading the infection), the researchers found no differences in the different age groups. Therefore, from these data, it would appear that children are less susceptible but equally contagious. This data reopens the discussion on the role of children in the spread of the virus and contrasts with other epidemiological data published previously ”, concludes the immunologist.