Twin girls who were born joined at the head, and separated last year by a team at Great Ormond Street Hospital in London, have returned home to Pakistan.
The UK is pushing ahead to be the first nation to carry out "human challenge" studies where up to 90 healthy people will be deliberately exposed to Covid
Anti-viral drug remdesivir has little to no effect on Covid patients' chances of survival, a study from the World Health Organization (WHO) has found.
Johnson & Johnson has paused its Covid vaccine trial to investigate why one participant in the study fell ill.
A man in the United States has caught Covid twice, with the second infection becoming far more dangerous than the first, doctors report.
Scientists are looking for volunteers to take part in a trial to see if taking vitamin D can give the immune system a boost against Covid.
Colds, flu and Covid-19 are caused by different viruses, but can have similar symptoms.
The virus responsible for Covid-19 can remain infectious on surfaces such as banknotes, phone screens and stainless steel for 28 days, researchers say.
Scientists in the UK have begun testing the BCG vaccine, developed in 1921, to see if it can save lives from Covid.
Thousands of scientists and health experts have joined a global movement warning of "grave concerns" about Covid-19 lockdown policies.
