Covid-19: a patient can infect half of the members of his household

It is very difficult to quantify the transmission of the coronavirus within households. However, this is the goal a team of researchers has set for themselves, thanks to a new study from the United States Centers for Disease Control and Prevention.

One of the barrier gestures to apply to limit the spread of Covid-19 is social distancing. This measure is difficult to comply with at home when a member of the household is contaminated with Covid-19. The risk of intra-family contamination exists and researchers have tried to measure its impact. According to their study, conducted in the Centers for Disease Prevention and Control, in America, sick people can infect half of their household members. Also, adults are slightly more likely than children to infect other people. Since April 2020, a home virus transmission assessment has taken place on 101 “index” patients from Nashville and Marshfield. The index patient is defined as the first patient in the household who shows symptoms and has tested positive for Covid-19. Scientists followed family contacts of these cases “index”, Asking them to keep a journal in which their symptoms are recorded, each day. They also received distance training to obtain samples ”self-collected”(Nasal swabs or nasal swabs and saliva samples), daily for 14 days.

Of the 101 zero patients, 191 reported having no symptoms on the day of disease onset in the index patient. Then, over the days, among the 191 family contact cases, 102 tested positive for Covid-19, for a secondary infection rate of 53%. Scientists specify that the secondary infection rate was 57% when the patient was over 18 and 43% for a younger age. The index child patients were few in number, hence “The generalization of results” made difficult for those under 18. In addition, 69% of index patients declared having spent more than 4 hours in the same room with one or more members of the household the day before and 40% the day after the onset of the disease. In addition, 40% of zero patients reported having slept in the same room as one or more people in the household before the onset of the disease and 30% after.

Whether the index patient is an adult or a child, the spread of the virus is significant. Secondary infections occurred rapidly with 75% of them identified within 5 days of onset of disease in the index patient. In addition, many of the household contact cases reported having no symptoms when the test result was positive. For scientists and health authorities, the measures must be taken very quickly within the home, when a person thinks they have been contaminated by Covid-19. The authors of the study recommend wearing a mask in the slightest doubt as well as quarantining the suspected person, to the extent possible.