The World Health Organization (WHO) today announced that it has listed the one-dose Johnson & Johnson COVID-19 vaccine for emergency use, which adds a more agile option for immunizing people in developing countries.In another vaccine development, the WHO said its safety committee is reviewing reports of blood clots in people who have received doses from certain batches of the AstraZeneca-Oxford vaccine, but emphasized that the vaccine can be used while the probe is underway.J&J green-light adds another COVAX optionGiven as one dose and stored at normal refrigeration temperatures, the Johnson & Johnson vaccine is the fourth COVID-19 vaccine to be listed for emergency use by the WHO, a key step that paves the way for it to be used in