A new Lancet Infectious Diseases study strengthens support for strict social distancing measures to help limit the spread of SARS-CoV-2, the virus that causes novel coronavirus disease (COVID-19).
Using simulation models, researchers in Singapore estimated the number of SARS-CoV-2 infections that would occur at 80 days after the first 100 cases of community spread were confirmed, assuming that 7.5% of infections were asymptomatic. In a scenario when the virus was least infectious (assuming each case infects another 1.5 people), a median 279,000 infections would occur by day 80. This would decrease with increasing social distancing measures, dropping to 1800 when all of the following were enacted: isolation of infected individuals plus family quarantine, workplace distancing, and school closures.
Of note, assuming a more infectious virus (one case infects another 2.5 people), there would be over 1.2 million infections at day 80 with no social distancing measures — and 258,000 with all measures in place.
Elsewhere, a JAMA viewpoint looks at the high case-fatality rate in Italy — 7.2% as of mid-March. The authors note this could be related to three factors: 1) nearly one-fourth of Italy’s population is age 65 and older; 2) some deaths may have been due to comorbid illness rather than the SARS-CoV-2 infection; and 3) mild and asymptomatic cases were rarely tested after late February and thus were not included in the denominator.