Achieving the goal of development of a safe and efficacious vaccine had a 6- to 18-month timeline. The unprecedented effort has generated over 200 candidates in various stages of development, with over 50 candidate vaccines in human clinical trials and 18 in efficacy testing⁴. To date, Pfizer/BioNTech has announced efficacy of 95%⁵; Gamaleya has announced efficacy of 92%; Moderna has announced efficacy of 94.5%; and AstraZeneca has announced efficacy of 70%^5,6. Sinopharm has now announced efficacy of 79%, and several countries participating in the Sinovac (another Chinese company) efficacy trials have announced efficacies (for the same product) of 50%, 65%, 78% and 91%^7,8. Sinovac has yet to comment, and these data have not been published or peer reviewed. Pfizer/BioNTech and Moderna are RNA vaccines expressing the coronavirus disease 2019 (COVID-19) spike glycoprotein, whereas vaccines from Gamaleya and AstraZeneca (partnered with Oxford University) express spike protein from adenovirus vector platforms. The vaccine developed by Gamaleya has a heterologous approach, with spike delivered in an adenovirus type 26 vector first, followed by a second dose containing spike in an adenovirus type 5, and AstraZeneca uses a chimpanzee adenovirus-expressing spike. Sinopharm and Sinovac have whole inactivated virus vaccines with alum as an adjuvant. However, effective vaccination is one part of effective, comprehensive control of the pandemic. In addition, scientific, social and political questions—around dose, schedule, ethics, effectiveness, surveillance and vaccine hesitancy—remain to be resolved, and pandemic control will require that some, if not all, of these issues be solved intercurrently. Source: Looking beyond COVID-19 vaccine phase 3 trials | Nature Medicine