Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

Professor Neil Ferguson of Imperial College was on the radio in Britain on Thursday making exactly this point. Referring to the outbreak in Italy he said: ‘for every person who dies we think there might be 100 or over 200 people infected.’

Asthma or other allergic diseases were not reported by any of the patients. Chronic obstructive pulmonary disease (COPD, 1.4%) patients and current smokers (1.4%) were rare.

Then there’s SARS, which is both deadlier than Covid-19 and has a similar R0. Why was it wiped out in about a year, while some experts warn that Covid-19 may be around forever? Because SARS usually didn’t become contagious until several days after symptoms appeared. This meant that, as four British infectious disease experts wrote in 2004, “actions taken during this period to isolate or quarantine ill patients can effectively interrupt transmission.” They proposed adding another variable to disease-transmission models: the proportion of transmission occurring prior to symptoms. For SARS, this was less than 11%, probably much less. For influenza, it is between 30% and 50%, making it far harder to control the disease’s spread.