- BBC News World
Many countries around the world are seeing a drastic increase in the number of covid cases, driven by omicron, the new variant of the virus.
But as omicron spreads, it seems to be becoming clear that the symptoms and disease it causes are less severe than those caused by their predecessors.
This means that people who become infected, especially if they are vaccinated, are less likely to be hospitalized or at risk of death.
That is why several countries are reviewing their regulations on the isolation period required for people infected with covid.
Here we explain how the omicron variant is changing what has been seen so far about the contagion of the coronavirus.
How long does it take for a person exposed to the virus to have symptoms?
Although there are still very few studies on omicron, what has been seen so far is that this variant is not only more contagious, but also has a shorter incubation period than previous variants.
Incubation is the time that passes from exposure to the virus until symptoms appear.
With the first variants of the coronavirus, symptoms generally appeared within five or six days after infection. With the delta variant they appeared in four days.
But from what is known so far with omicron, the incubation period it is two to three days.
“Basically [con ómicron] It seems that replication is very fast, “explains Dr. Vicente Soriano, a doctor specializing in infectious diseases and clinical genetics and a former adviser to the World Health Organization.
“After being sneezed in the face, replication [del virus] it starts in one day and after two days it is already detectable [con síntomas]”, adds the professor from the International University of La Rioja, Spain.
Indeed, a preliminary study of six cases of omicron in the United States, published in December, found that the average incubation period was three days, compared with around five days for other variants.
How long does a contagious person remain at risk of infecting others?
It is known that people tend to be most contagious early in their infection.
With omicron, it is believed that the virus can be transmitted one to two days before the onset of symptoms and two to three days after.
“We believe that the virus is only contagious for five days. That is, the ability to infect others, to transmit that virus lasts for three to five days after the test is positive, which is day two of infection”, says the expert.
Thus, with omicron, the time that the virus remains in the body appears to be only seven days.
“But this is medicine, not mathematics, so you have to give a little margin. Maybe there are people who last a little less, about three or four days, and others about seven days. The truth is that with omicron the infection it is much faster than with previous variants “, adds Vicente Soriano.
This means that about seven days after symptoms appear, most people will no longer be contagious as long as they no longer have symptoms.
The expert underlines lthe importance of undergoing antigen testing (also called rapid lateral flow tests) to detect if the person is still contagious.
“They are cheaper tests and are the best reflection of the cases that are still contagious.”
Because omicron appears to have a shorter period of infection than other variants, several countries have reduced the time that infected people should isolate themselves.
In the United States, isolation was reduced from 10 to five days and in the United Kingdom, it was reduced from 10 to seven days with evidence of two negative antigen tests.
When can I be with other people if I have covid and have symptoms?
According to the US Centers for Disease Control and Prevention (CDC), if you test positive for covid you must:
- Isolate yourself at home for five days.
- If you no longer have symptoms or your symptoms are improving after five days, you can leave the isolation and leave your home.
- Continue wearing a mask when you are with other people for another five days.
- If you have a fever, continue in isolation at home until the fever clears.
What happens if an infected person has no symptoms?
With covid it has been seen that there are people who do not present symptoms during the entire course of their infection.
As explained by the infectious diseases specialist Vicente Soriano, with omicron it would be expected that asymptomatic infection was similar to infection with symptoms.
“Much is still unknown about asymptomatic infections. But the duration of the contagion has to be similar to that of people who have symptoms,” he says.
“There are studies of covid in children, who usually do not present symptoms, and show that the viral load they have, although they do not present symptoms, is the same as that of adults who have symptoms.”
Experts note that a person who tests positive for COVID but never developed symptoms will likely no longer be contagious after 10 days.
Can a person without symptoms spread it to others?
Studies have shown that people with covid who have no symptoms can transmit the coronavirus infection to other people.
Research published in the JAMA Network Open (Journal of the American Medical Association) found that nearly one in four infections can be transmitted by people with asymptomatic infections.
It is thought that the proportion of asymptomatic transmission appears to be even higher with the omicron variant.
The infection is more likely to be transmitted to people without symptoms as they will not isolate themselves and will not adopt behaviors to prevent the spread of the virus.
That is why the authorities recommend the use of masks, particularly indoors, to help reduce the risk that someone who is infected but not experiencing symptoms may unknowingly spread it to others.
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Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.