- 'Reaching the limit' -Cases have soared past 101 million worldwide, and despite the rollout of vaccines, the fight has been further complicated by the emergence of more contagious variants first detected in Britain, Brazil and South Africa.American biotech firm Novavax said Thursday that its vaccine showed an overall efficacy of 89.3 percent in a major British clinical trial, and was highly effective against the variant first detected there.But other results showed it offered significantly less protection against the South African strain.Mozambique's President Filipe Nyusi has warned that warned hospitals across southern Africa are "rapidly reaching the limit of their capacities", in part down to the new variant.Pfizer and Moderna have.