Recovered patients' immunity lasts at least 6 months: Swedish agency

STOCKHOLM • Sweden's top health authority said people who have had the coronavirus are likely to be immune for at least six months after being infected, whether they have developed antibodies or not.

In new guidance published on Tuesday, the Swedish Public Health Agency said it is now considered safe for individuals who had been infected to come into contact with people in high-risk groups.

"We don't see cases of people falling ill twice from Covid-19," state epidemiologist Anders Tegnell said during a press conference in Stockholm. "Hence, our assessment is that if you do get Covid-19, you are immune even if you don't develop antibodies."

But the agency also said people deemed to be immune can still act as carriers of the virus, and must therefore continue to observe social distancing and hygiene guidelines.

The antibody response to Covid-19 is being closely studied by scientists around the world for indications of how long-lasting such immunity may be.

Research from Sweden's Karolinska Institute has indicated that about twice as many people infected by Covid-19 have developed a T-cell mediated immunity response as those who have a detectable level of antibodies.

T-cells appear to play an important role in protecting against reinfection with Covid-19.

On Tuesday, Dr Tegnell said Sweden "probably" has achieved a fairly high rate of immunity, which he predicts will protect his country from new outbreaks. He remains a controversial figure for his decision to advise against imposing a proper lockdown in Sweden.

BLOOMBERG