Isolation for five days: a good idea?

Some Canadian provinces, as well as the United States, have reduced the isolation of doubly vaccinated people who contracted COVID-19 to five days. In Quebec, the isolation period remains, for the moment, of 10 days. But last week, the Department of Health announced that a doubly vaccinated healthcare worker infected with COVID-19 could return to work after seven days in isolation if a disruption in service threatens his workplace. Should we take inspiration from what is being done elsewhere? Press spoke with experts to answer the question.

Coralie Laplante
Press

Q. Initially, why was it determined that the solitary confinement was to be for 10 days?

R. This decision was based on the study of the original COVID-19 virus, says D^r Donald Vinh, infectious disease specialist and microbiologist at the McGill University Health Center.

“We know that when you are infected, the incubation period, that is to say the time between exposure [et] the development of symptoms or disease is about five to seven days. Corn [on sait] that the transmissibility period is roughly seven to ten days, ”says Vinh. “We even know that [pour] immunosuppressed people, it can be weeks, ”he adds.

However, little data is currently available on the Omicron variant, says Dr.^r Quoc Dinh Nguyen, geriatrician and epidemiologist at the Center hospitalier de l’Université de Montréal. He recalls that at the start of the pandemic, a 14-day isolation was requested from people who had been in contact with a person infected with COVID-19.

“It was said that around 95 [à] 97% of people, after 14 days, if they had not yet developed symptoms, were not going to develop any ”, according to studies, specifies D^r Nguyen.

Q. Can I get a negative COVID-19 test after five days?

R. Yes it’s possible. “We can have people who are infected, and in the first five days, they are able to eradicate the virus from their respiratory tract, and there are other people who are not able,” says Donald Vinh.

Q. Do people who have received a double vaccine stop being contagious faster?

R. Study on the Delta variant has shown that people with a double vaccine get rid of the virus faster, says Dr.^r Quoc Dinh Nguyen.

Experts believe that this process probably also applies to the Omicron variant, “because there are fewer severe forms. [de la maladie], and because the variant does not completely escape our vaccines, especially after three doses, ”says Dr.^r Nguyen.

The explanations of D^r Vinh go in this direction. A study from Singapore has shown that the period when doubly vaccinated people infected with the Delta variant can transmit the virus is around seven days, he says.

“It was one of the studies which showed that if we are doubly vaccinated, in particular against the Delta variant, the vaccine not only protects us against the severity of the disease, but also decreases the period of transmission,” says Donald Vinh.

Q. After five days, what proportion of people infected with COVID-19 are still contagious?

R. To date, it is impossible to answer this question exactly because of the limited data available on the Omicron variant, recalls Quoc Dinh Nguyen. But a study carried out in Taiwan which looked at 23 patients with the Omicron variant found that after five days, 17 of the 23 people had a viral load low enough to come out of their quarantine, or nearly 74%, points out. the D^r Nguyen.

As for the Delta variant, 20 to 25% of people with the disease may still be contagious after five days (that is, 75% to 80% no longer), explains Donald Vinh. However, these data may be different with regard to the Omicron variant. The effects of the third dose of vaccine on the transmissibility of the virus are also to be studied, says Dr.^r Vinh.

Q. Should Quebec also reduce the duration of the isolation of double vaccinated people to five days?

R. It “could be a little premature if we only use five days as a threshold, without being able to strengthen it with an additional screening,” said Donald Vinh. He recalls that models suggest that a person should get two negative drug tests around the fifth day of quarantine before being released.

This is the case in England. The country is asking that a person infected with COVID-19 get a negative COVID-19 test on the sixth and seventh days of their isolation before they can end it.

“I personally find that imposing something like the CDC [les Centres pour le contrôle et la prévention des maladies américains] it would be premature, by and large, to take just five days like other provinces do. Nevertheless, if the breakdowns of services become totally generalized, it is sure that it is a think-it-well ”, affirms for its part the D^r Nguyen.

In the United States, the CDC has indeed recommended reducing the isolation of an infected person to five days, rather than ten. However, if we “read at length” the opinion of the CDC, the organization recommends taking a test for COVID-19 before ending his isolation, explains Quoc Dinh Nguyen. But rapid tests are difficult to access in the United States, as in Canada.

“The CDC didn’t want to link its measurement directly with testing. However, that would be the right way to go, ”says Nguyen.

Sunday evening, the White House adviser on the health crisis, D^r Anthony Fauci, revealed that the CDC is considering including a negative COVID-19 test in their recommendations before ending his isolation.