New York, New Jersey, and Connecticut have just moved to restrict travel from hot zones around the country. The states that had the worst Spring outbreak (and whose residents were quarantined by Florida and others) are now requiring Florida and other states’ residents to quarantine for 14 days. As they might say, “turnabout is fair play”. A single figure of merit that is not arbitrary or capricious is not easy to agree on, but their definition for current hotness sounds reasonable: more than 10 confirmed COVID-19 cases per 100,000 residents based on a rolling 7-day average. The table below lists the 8 official ignominious states plus California (CA) which qualified yesterday. We also include the infection reproduction rate R, and the doubling time for each state as indicators of how fast infections are growing in each state. The doubling time might also be used as a gating criterion since a state with low current hotness might have a very short doubling time and qualify for the list quickly.
To truly minimize USA reinfections, we had argued that the US needs to update the restricted travel countries list to include many countries that are currently hot and remove countries that are not. The table below lists some of the potential countries and their 7-day hotness measure. As you can see NY, NJ, CT could quarantine the entire USA by their gating criteria. The USA not only qualifies on a rolling 7-day infection basis but it is also growing faster than other highly troubled countries such as Brazil. Russia and India should be considered for the restricted travel list because both have huge infections that are managed to look good but are probably out of control. Others, such as countries in Europe should be considered for removal from the CDC restricted travel list.
Broad quarantines are crude and often political instruments that should only be used as a last resort. If a state fails to execute good practices such as masking, social distancing, testing, contact tracing, and selective isolation, it may be the only tool left to control a pandemic. The CDC has now come out to downplay the efficacy of out-of-state quarantines, but they offered no evidence to the contrary and no alternative policy or procedure to minimize reinfections. This is one of the dangers of not having a quick and decisive Federal response to the Pandemic in the first place.