Last month, Governor Charlie Baker issued a statewide mandate that anyone arriving in Massachusetts from any state outside of New England, New York, and New Jersey after Aug. 1 is required to quarantine for 14 days, but with the potential to “test out” of this requirement if they obtain a negative result on a coronavirus test within 72 hours of travel. In contrast, new residents in the state’s nursing homes must quarantine for 14 days, without any testing out allowed. Nursing homes account for 63 percent of COVID-19 deaths in Massachusetts and 40 percent nationally. Both rules need to be revised based on the available evidence.
The 14-day quarantine rule is based on the time from infection to symptoms, which for COVID-19 is typically between three and five days; and most people can spread the infection for up to 10 days after symptoms. People who are infected with COVID-19, but never develop symptoms, are also infectious for up to 14 days after the date they became infected.
Experience in nursing homes has confirmed that a single negative coronavirus test is not enough to establish someone is COVID-19 free, and that surveillance testing of everyone is needed to identify asymptomatic cases before they lead to major outbreaks. The state health authorities have wisely taken these lessons on board and now fund a regular surveillance virus testing program for residents and staff in long-term care facilities, in which a rotating sample of people is tested every week.
In contrast, the current test-out rule for travelers is at odds with the known facts. COVID-19 is a disease that moves fast, and it would be easy for a person to become infected after taking their pre-travel virus test, or even en route to Massachusetts. Requiring an additional test immediately upon arrival would also not solve the problem, since testing a person too early in the course of the infection is a sure-fire way to get a false negative result.
A sounder approach would require travelers from hot spots to quarantine (no face-to-face contact with others) on arrival and to take a second coronavirus test no earlier than the fifth day after their previous test. Our protocol for incoming college students, people returning from vacation, and business travelers would therefore be:
▪ An initial coronavirus test three days before travel to Massachusetts. If the virus test is negative, you may travel. If the virus test is positive, do not come to Massachusetts until 14 days have elapsed. No further testing is necessary after someone who tested positive has quarantined fully for 14 days.
▪ For those with a negative first test, a second COVID-19 test should be obtained after arrival in Massachusetts, but this must be at least five days after the negative pre-travel test. Quarantine upon arriving in Massachusetts and as much as possible before traveling here. If this second virus test is negative, the quarantine is over. If the second virus test is positive, an additional period of quarantine (measured from the day of the second test) of 12 days is required — because you may have been infected in transit.
Within a month, at least 100,000 students will arrive in Massachusetts, of whom probably a third are in places where the disease is raging out of control. Many young people themselves may not be at great risk of complications, although no one should take this virus lightly. But students can easily spread the disease to other students, to faculty and staff, and to vulnerable people throughout our community. Without an effective public health surveillance strategy in place, we could be facing hundreds of potential outbreaks this fall due to false negative tests prior to arrival. Fortunately, available testing capacity in Massachusetts (45,000 tests per day) is more than enough to handle post-arrival testing for all students before they are released from quarantine.
For new arrivals into nursing homes, a blanket two-week quarantine period has serious consequences for residents who were recently hospitalized for serious illness and need intense physical and mental rehabilitation for recovery. Therefore, we propose that the new quarantine test-out rules for travelers also be applied to new residents entering nursing homes. This makes intuitive sense as the issue is the same in both instances: to prevent the introduction of COVID-19 into a population by people arriving from another location. The strategy of two virus tests at least five days apart would significantly reduce isolation time while maintaining the safety of the community.
Another helpful modification of current testing practice would the reporting of cycle threshold values, a measure of how much virus is present on the patient. The state should require labs to make CT values readily available for clinicians, since tracking these numerical values across tests can help physicians determine whether a test is positive due to the presence of infectious virus or because it is picking up remnants of the viral genome.
More broadly, the best way to track human health relative to COVID-19 is using serologies, i.e., a blood test that looks for the presence of antibodies produced specifically against the virus. There are now inexpensive and highly sensitive tests (meaning a low rate of false negatives) that can detect the presence of COVID-19-specific antibodies. These tests require only a single drop of blood and can provide fast turnaround for results.
Irrespective of the quarantine rules and the frequency of regular testing, all nursing home residents and college students should have regular antibody tests, to track who becomes infected, when they recover, and who remains susceptible. Based on this information, additional preventive measures can be put in place — more virus testing, greater use of personal protection equipment, and selective restrictions on activities, e.g., for particular dorms or nursing homes — that can help forestall major outbreaks.
We cannot realistically prevent all COVID-19 transmissions, but we can certainly leverage the hard-won knowledge we have gained over recent months to prevent the disease from again getting out of control. A revision of quarantine rules for incoming travelers and nursing home residents is urgently needed.
Simon Johnson is a professor at MIT’s Sloan School of Management and cofounder of the Immune Observatory. Dr. Sanjat Kanjilal is a lecturer in the Department of Population Medicine at Harvard Medical School and Harvard Pilgrim Healthcare Institute, and an infectious diseases physician and an associate medical director of microbiology at Brigham and Women’s Hospital. Dr. Larissa Lucas is a medical director at North Shore Physicians Group and a nursing home medical director.