masking and isolating reduced omicrons spread in homes cdc study finds healthmasking and isolating reduced omicrons spread in homes the cdc finds moran for the new york timesfeb 25 2022the omicron variant of the coronavirus has been so contagious that it may have seemed a foregone conclusion that if one person in a household became ill other people living there would catch the virus toobut that turns out to be less certain a small study of households by the centers for disease control and prevention released on friday found that when the first person infected wore a mask and stayed in a separate room at least part of the time the risk of other household members contracting the virus became markedly lowervaccinated people who became infected were also considerably less likely than unvaccinated people to spread the virus to other members of their householdsstill the study highlighted just how aggressively the omicron variant had spread within a home especially among people living with children under 5 who tested positive those children who are not yet eligible for vaccines and often need to be in closer contact with their parents or relatives spread the virus to 72 percent of household contacts identified in the study the highest rate of any age group the cdc saidthese findings further highlight young childrens potential contribution to household transmission cdc scientists wrote in the reportfederal regulators are waiting for data on how well three doses of the pfizerbiontech coronavirus vaccine work in children under 5 before deciding whether to authorize the vaccine for that age groupthe cdc study was based on 183 households across four states where someone became infected with the omicron variant from november to early february after interviewing members of the households about their vaccination and infection histories any precautionary measures in the home and whether they had tested positive or become ill cdc scientists determined that the variant had spread in roughly twothirds of the households they identifiedbut when the first infected person was fully vaccinated only about 44 percent of household members developed covid compared with 64 percent when the infected person was unvaccinated the study saidand when the original infected household member stayed in a room alone at least some of the time only 41 percent of other members of the household became infected compared with 68 percent in situations without isolation masking by the infected person helped too reducing the likelihood of transmission to 40 percent from 69 percentdetermining the precise risk of the virus spreading in a home was difficult the studys authors noted they excluded situations where it was unclear who had first developed covid and did not do the genetic sequencing necessary to know for certain that people had caught the virus from the infected person in their home rather than at other gatherings