BEIJING : Novel coronavirus that causes Covid-19 may spread more easily among people living together and family members than severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS), says a new study published in The Lancet Infectious Diseases journal.The analysis, based on contact tracing data from 349 people with Covid-19 and 1,964 of their close contacts in Guangzhou in China, found people with Covid-19 were at least as infectious before they developed symptoms as during their actual illness, and that older person (aged 60 years or more) were most susceptible to household infection with SARS-CoV-2 (coronavirus)."Our analyses suggest that the infectiousness of individuals with Covid-19 before they have symptoms.