While the US Centers for Disease Control and Prevention has said that people who have recovered from Covid-19 do not need to quarantine or get tested again for up to three months, the agency said in a statement to CNN that does not mean that they are immune to reinfection.
Last week, the agency updated its guidance on who should quarantine to say: "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. People who develop symptoms again within three months of their first bout of Covid-19 may need to be tested again if there is no other cause identified for their symptoms.
In a statement emailed to CNN on Friday, a CDC spokesperson said the guidance is “based on the latest science about COVID-19 showing that people can continue to test positive for up to three months after diagnosis and not be infectious to others.”
Yet "this science does not imply a person is immune to reinfection with SARS-CoV-2, the virus that causes COVID-19, in the 3 months following infection. 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 statement noted that people with Covid-19 should be isolated for at least 10 days after showing symptoms and until one day after their fever subsides without the use of fever-reducing medications.
"There have been more than 15 international and US-based studies recently published looking at length of infection, duration of viral shed, asymptomatic spread and risk of spread among various patient groups," the statement said. "Researchers have found that the amount of live virus in the nose and throat drops significantly soon after Covid-19 symptoms develop. 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."
The statement added that CDC will continue to closely monitor the evolving science for information that would warrant reconsideration of these recommendations.