Two European patients were confirmed to have been re-infected with the coronavirus, raising concerns about people’s immunity to the virus as the world struggles to tame the pandemic.

A roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for Covid-19, the illness caused by the virus.

BioSpace reviews some of the more interesting scientific studies recently published, including a Phase II clinical trial out of Hong Kong that found a three drug-antiviral cocktail significantly decreased median time to a negative SARS-CoV-2 test compared to controls.

The World Health Organization (WHO) said it was “a bit too early” to declare a new coronavirus a global health emergency as China put millions of people on lockdown amid an outbreak that has killed 18 people in the country and infected around 650 globally.