[ad_1]
Tests on leaving quarantine – ideally around the sixth or seventh day – are more effective than on entry, and testing twice could make an eight-day quarantine as effective as a 14-day quarantine.
As Americans are considering how to safely reunite with their families on Thanksgiving, a new study that includes data from workers at offshore oil rigs could help clarify the best strategy.
The question of reuniting with the family for the holidays is thorny. the notDr Anthony Fauci, the foremost infectious disease specialist in the air, urged Americans to skip Turkey Day altogether. Data from Canada, where Thanksgiving is celebrated in October, highlights the risks of getting together in large groups for the occasion. Canadian public health officials have attributed an acceleration in Covid-19 cases to the festivities. So perhaps it’s no surprise that in the United States, a poll found that 21% of people have put their regular Thanksgiving travel plans on hiatus – but 39% still plan to travel during vacation.
Many epidemiologists have recommended a two-week quarantine before reuniting with loved ones to avoid spreading the coronavirus during Thanksgiving. Two weeks is also the time that the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization recommend quarantining if you’ve been exposed to someone who has tested positive. for the SARS-CoV-2 virus. which causes Covid-19. (This is different from self-isolation for people who have tested positive, which lasts about 10 days and is shorter since the incubation period has already passed.) Of those infected with the coronavirus, about 98% of people will develop symptoms by day 12 of quarantine, some research has shown, and the median incubation time is five days.
“It makes no sense to use unduly restrictive quarantines while eating indoors.”
But given the financial and mental health drawbacks of long quarantines, some rules for travel-related quarantine change. The CDC moved away from a 14-day quarantine for international travelers at the end of the summer. On November 3, New York implemented new guidelines allowing out-of-state travelers to test out of the mandatory 14-day quarantine if they get two negative tests – one before their trip begins. the state and four days after. Meanwhile, Alberta, Canada, is piloting a program in which some travelers can take a test at the airport. Participants can leave their quarantine if and when the results are negative, which usually takes two days, and they must also get a second test four or five days after that.
Now, however, researchers say they have combined data on various aspects of Covid-19 that offers a more complete picture of how to shorten the standard 14-day quarantine.
In a new study, Jeffrey Townsend, a biostatistician at the Yale School of Public Health, and his collaborators created a model using existing data on how infectious people with Covid-19 are at different points in their illness, as well as information on the accuracy of so-called PCR tests for the disease at these times. Importantly, the model also takes into account data from other studies on the incubation period of SARS-CoV-2. The latter is especially important since infected people can spread the disease several days before they start to feel sick (and some infected people never develop symptoms).
The study, which originally went online on October 28 and has yet to be approved by other scientists for publication in a scientific journal, suggests that an eight-day quarantine in which people are tested on entry on day 1 and again on day 7 before discharge on day 8 (as it usually takes one day for PCR test results) is just as effective as a 14-day quarantine without testing. However, it is not possible to test twice in many places, so the authors also modeled whether it would be better to test before or during quarantine. They concluded that post-quarantine testing – ideally around the sixth or seventh day, when the amount of virus in the body has reached detectable levels – is more effective than entry testing.
The results are in line with a previous study by a UK group published online this summer which, based on modeling simulations, suggested that an eight-day quarantine with PCR testing on the seventh day would provide protection similar to a period 14-day quarantine. However, the new study by Townsend and colleagues went further and validated some of its findings by testing the recommendation with the Australian company BHP, which conducts offshore oil drilling.
BHP had previously instructed its workers to quarantine in a hotel on land before deploying to the offshore drilling site as a precaution, as conditions on the rig involve close living and working quarters where Covid- 19 could easily spread. But the study results also prompted the company to implement exit testing. “They were incredibly receptive” to change, says Townsend. Once the new protocol was put in place, he identified 16 of the 1,026 people who tested negative on the entry test, but then tested positive on the second test. Without the second test, they might not have been detected as carriers of the virus and would have left for offshore platforms. Townsend says he has heard that the news about the importance of exit testing is prompting other companies to rethink their approach: “Other oil companies have heard of the effectiveness of BHP’s work in preventing epidemics, and this [approach] migrated through the industrial sector. “
“I think these results are significant because they help make quarantine less burdensome for people.”
The new study’s proposal to shorten the 14-day quarantine using carefully timed testing is a step in the right direction, says David Fisman, an epidemiologist at the University of Toronto’s Dalla Lana School of Public Health. “It makes perfect sense,” says Fisman. “We know that Covid crosses borders. It makes no sense to use unduly restrictive quarantines while eating indoors, ”he adds, noting that more concerns should be directed to the potential for further spread of events in the latter situation.
“I think these results are significant because they make quarantine less burdensome for people,” says Angela Rasmussen, virologist at Columbia University. “However, it strongly depends on the testing capacity. Without sufficient testing, this will not be possible. Laboratories across the United States have struggled to meet demands for Covid-19 testing.
Ronald Fricker, professor of statistics at the Virginia Polytechnic and State University, says the shortened quarantines supported by the new work have many benefits. “In addition to the obvious economic benefits for people who can return to work faster, it could also improve public health practices, as shorter quarantine times are likely associated with higher compliance rates,” says Fricker. “Simply put, people are more likely to stay in quarantine for a week rather than two weeks. Plus, shorter timelines mean quarantine is less of a logistical and mental health burden for people.
Townsend, for his part, says his family has no travel plans and is staying home in isolation for Thanksgiving. “As an epidemiologist doing this kind of work, you would feel like a hypocrite if you didn’t take the most extreme precautions,” he says. Townsend adds, however, that his wife and three children will always mark the occasion, albeit in a smaller version: “We’re going to have a Thanksgiving meal, and it will be fun and it will be great.”
[ad_2]
Source link