Researchers in the US and UK have identified hundreds of mutations to the virus which causes the disease Covid-19.
But none has yet established what this will mean for virus spread in the population and for how effective a vaccine might be.
Viruses mutate – it’s what they do.
The question is: which of these mutations actually do anything to change the severity or infectiousness of the disease?
Preliminary research from the US has suggested one particular mutation – D614G – is becoming dominant and could make the disease more infectious, and perhaps more severe.
But it hasn’t yet been reviewed by other scientists and formally published.
The researchers have been tracking changes to the “spike” of the virus that gives it its distinctive shape,