The transmission time of covid indicated by health authorities has changed over the course of the pandemic. See in Mariana Varella’s column.
At the beginning of the pandemic Covid-19when there was still not much information based on evidence about the behavior of Sars-CoV-2, nor vaccinesexperts recommended 14-day isolation for anyone who contracted the virus.
For the time being, with the increase in vaccination and testing coverage and the circulation of new, more contagious variants, such as omicron, there were changes in the contagion period, which began to focus on the two days prior to the onset of symptoms and the first three days after the onset of the condition. Thus, health bodies changed the recommendations for isolation.
See also: Covid-19: Know the symptoms of each variant
However, many people who caught covid continue to have doubts: how many days exactly should I be isolated at home? Do I need to test to see if I’m still contaminating before leaving isolation? What if I don’t have symptoms?
The US Centers for Disease Control and Prevention (CDC), which sets out protocols followed by experts around the world, has prepared a series of rather complicated recommendations for laypeople.
The first confusion concerns what is considered day 1 of infection, from which the days of isolation should be counted. For the Center, the day on which symptoms appear is day 0, so day 1 is the day after the onset of symptoms (full 24 hours).
In addition, some doctors and scientists believe the CDC should recommend that people get tested before leaving isolation, which the agency puts only as an option.
How long should I remain isolated?
The person suspected of having come into contact with Sars-CoV-2 must, first of all, undergo the test to confirm the diagnosis, even if they do not have symptoms. In this case, the test must be done at least 5 days after contact.
If you have symptoms and a positive test, you should, according to the CDC, stay at home for 5 days and wear a mask until the tenth day after the onset of symptoms (remember that day 1 is the second day of the onset of symptoms), whenever you are around other people, indoors or out. This, however, is valid if the symptoms are progressively improving and the patient has not had a fever for at least 24 hours.
Anyone who has severe symptoms and is not improving after the fifth day should remain isolated for 10 days.
Anyone who has a positive test, but does not manifest symptoms, must isolate for 5 days, starting to count day 0 as the day the test was performed, and wear a mask, at home or outside, for 10 days.
While it is unlikely that a person will continue to transmit the virus for days after symptoms start, it is possible that this will happen. However, after the tenth day, it is very difficult to infect other people, even if the test is still positive.
Who has access to self testswhich cost between 30 and 80 reais, you will be more confident if you can take an exam before leaving isolation, after five days, especially if you are going to attend meetings or events with many people or come into contact with older, unvaccinated or with health problems.
Regarding tests, it is good to remember that there are two types available for the diagnosis of covid, PCR and antigen tests, also called “rapid tests”. The first detects the genetic material of the virus and is better suited to confirm or refute the infection, but it is not recommended to say whether a person is at risk of infecting others.
In addition to being a very sensitive test, which can continue to be positive even some time after infection, PCR takes a few days to be ready. To find out if you are still at risk of passing the virus, it is recommended that after the 5-day period of isolation you do the rapid antigen test.