J&J: Single-dose regimen vaccineThe vaccine from Johnson &Johnson is the first to be listed by WHO as a single dose regimen, which should facilitate vaccination logistics in all countries. "The ample data from large clinical trials shared by the company also shows that the vaccine is effective in older populations," according to the global health body."To expedite listing of the vaccine, WHO and a team of assessors from all regions adopted what is called an 'abbreviated assessment' based on outcomes of the EMA review, and evaluation of quality, safety and efficacy data focused on low- and the middle-income country needs.