(FILES) A file photo taken on November 17, 2020 shows vials with Covid-19 Vaccine stickers attached and syringes with the logo of US pharmaceutical company Johnson & Johnson. - The Johnson & Johnson vaccine is highly effective against severe Covid-19, including against the South African and Brazil variants, new documents released by the US Food and Drug Administration showed on February 24, 2021. In large clinical trials, the vaccine efficacy against severe disease was 85.9 percent in the United States, 81.7 percent in South Africa, and 87.6 percent in Brazil. (Photo by JUSTIN TALLIS / AFP)