The virus, technically known as SARS-CoV-2, causes the disease COVID-19.
Newly updated science on people not being able to spread the virus for up to three months “does not imply a person is immune to reinfection with SARS-CoV-2,” the health agency said in an Aug. 14 statement.
“The latest data simply suggests that retesting someone in the 3 months following initial infection is not necessary unless that person is exhibiting the symptoms of COVID-19 and the symptoms cannot be associated with another illness.”
The clarification referred to the CDC’s recently updated recommendations for when and for how long patients with the disease should quarantine.
CDC researchers wrote that people who have been in close contact with a COVID-19 patient should quarantine, unless they have had the disease themselves within the past three months.
“People who have tested positive for COVID-19 do not need to quarantine or get tested again for up to 3 months as long as they do not develop symptoms again,” researchers wrote on the agency’s website.
“People who develop symptoms again within 3 months of their first bout of COVID-19 may need to be tested again if there is no other cause identified for their symptoms,” they added.
Some believed the advice suggested people were immune to the CCP virus for three months after contracting the illness.
In the updated guidance, the health agency states that people with confirmed cases of the new disease should isolate for at least 10 days after beginning to show symptoms and until 24 hours after their fever subsides without the use of fever-reducing medicine.
“There have been more than 15 international and U.S.-based studies recently published looking at length of infection, duration of viral shed, asymptomatic spread, and risk of spread among various patient groups. Researchers have found that the amount of live virus in the nose and throat drops significantly soon after COVID-19 symptoms develop,” the CDC said.
“Additionally, the duration of infectiousness in most people with COVID-19 is no longer than 10 days after symptoms begin and no longer than 20 days in people with severe illness or those who are severely immunocompromised.”
COVID-19 is a disease that primarily affects the elderly and those with compromised immune systems. It causes symptoms in some patients, including loss of taste or smell, fever, and chills. Others show no symptoms or very light symptoms.
A small percentage of people with the disease die. In the United States, that percentage is well under 1 percent.
Researchers haven’t yet found whether patients who get the disease are then immune to it, and, if so, for how long the immunity lasts.
Dr. Scott Atlas, President Donald Trump’s new CCP virus adviser, said last month that emerging data “shows that people have immunity—even people that didn’t get the infection,” adding, “That’s probably due to this T cell immunity, which is present, and is now known to last for years.”
Atlas, speaking during an appearance on Fox News, pointed to research from Singapore and from Sweden’s Karolinska Institute. Researchers from the institute stated in a paper published in preprint on June 29 that many people with mild or asymptomatic cases of COVID-19 demonstrate T cell-mediated immunity to the CCP virus.
“T cells are a type of white blood cells that are specialized in recognizing virus-infected cells, and are an essential part of the immune system,” Marcus Buggert, assistant professor at the Center for Infectious Medicine at the institute and one of the paper’s authors, said in a statement.
“Advanced analyses have now enabled us to map in detail the T cell response during and after a COVID-19 infection. Our results indicate that roughly twice as many people have developed T cell immunity compared with those who we can detect antibodies in.”
Dr. Anthony Fauci, the director of the National Institute of Allergies and Infectious Diseases at the U.S. National Institutes of Health (NIH), said in the spring that it’s reasonable to assume “that when you have an antibody, you are protected against reinfection,” although that hasn’t been proven for the new coronavirus.
Last month, Fauci said in a discussion with Dr. Francis Collins, the NIH director, that it isn’t clear how long antibodies protect patients who contract the illness.
“We’re going to assume that there’s a degree of protection, but we have to assume that it’s going to be finite,” he said, adding that a CCP virus vaccine wouldn’t be like a measles vaccine, which typically confers immunity for life.