Scientists fear mutating virus means Covid-19 is likely to cause significant number of illnesses and deaths for years to come
Scientists interviewed by Reuters news agency have warned that data on new variants suggests Covid-19 will remain a threat for years
Optimism following the production of several effective vaccines has dimmed somewhat in the face of the new variants, scientists said
Vaccination is still vital to fighting Covid-19 but other measures will likely need to continue and jabs will need to be constantly updated to address new strains