Geneva: The WHO's expert vaccine advisers said Wednesday they could recommend the Johnson and Johnson jab for use in countries where variants of the new coronavirus are circulating. The vaccine, which can be used on people aged 18 and above, has proven effective "in the countries where there is a high spread of the variants", Alejandro Cravioto, the head of the World Health Organization's Strategic Advisory Group of Experts (SAGE) on Immunization, told reporters. Johnson & Johnson’s long-awaited vaccine appears to protect against COVID-19 with just one shot - not as strong as some two-shot rivals but still potentially helpful for a world in dire need of more doses.