People who have recovered from Covid-19 need not quarantine themselves for up to three months after they have recovered, the American Centers for Disease Control (CDC) said in recently updated advisories for their citizens, the first time public health officials anywhere have expressed confidence in some duration of immunity infected people develop.

The advisory was available on the website of US CDC which, according to New York Times, appeared to suggest that it was safe for people to mingle with others for three months.

“People who have tested positive for Covid-19 do not need to quarantine or get tested again for up to three months as long as they do not develop symptoms again,” said the guidance on cdc.gov.

If someone does develop symptoms – such as cough, fever or difficulty breathing – they “may need to be tested again if there is no other cause identified for their symptoms”, the advisory added.

Scientists around the world are yet to conclusively determine the question of how long immunity may last after a Covid-19 infection, which first began infecting humans a little over eight months ago. In this period, studies have indicated the antibodies – proteins in the human body that can prevent a re-infection with a pathogen – wane over two to three months. At the same time, there are also studies – including one from Wuhan published on Thursday – that showed antibodies lingered on for over six months. People may also be protected by something known as memory T cells, a part of the immune system that learns how to fight infections. T cell memory may not necessarily prevent an infection but can quickly ramp up the production of antibodies and killer immune cells that can prevent a serious bout of Covid-19 second time around.