 Pfizer-BioNTech vaccines at an immunization center in Tel Aviv, Israel |
Countries around the world have reported new variants of the coronavirus that appear to spread more easily.
A strategic adviser at the WHO said organizations run short of safety and efficacy data in clinical trials of two Pfizer vaccines doses within 21-28 days. He recommended delaying the administration of the second dose for a few weeks in order to maximize the number of individuals benefiting from a first dose.
