Effective Reproduction Number (Rt)
The most recent data suggests an Rt rising above 1.0 in early January, but returning to levels below 1.0 until early February when it briefly spiked. Time will tell whether this February spike was isolated, stemming from a single day’s reporting of a large number of cases.
Given the single day’s large number of cases reported in early February, estimates for the coming two weeks are somewhat unstable. The most likely course seems to be a slight increase in cases, but this projection could be an artifact of the above-mentioned single day numbers.
Asymptomatic to Symptomatic Ratio
The ratio of asymptomatic to symptomatic cases appears to have remained largely stable at relatively low levels over the last 6 weeks, with the exception of a brief spike in early February. A low ratio of asymptomatic to symptomatic cases facilitates mitigation efforts since symptomatic individuals usually isolate.