Placebo-Controlled Trials of Covid-19 Vaccines — Why We Still Need Them

Biostatistics faculty members Tom Fleming and Betz Halloran sit on the WHO Ad Hoc Expert Group on the Next Steps for COVID-19 Vaccine Evaluation. In a recent New England Journal of Medicine article, the group notes that even though the efficacy of some COVID-19 vaccines appears to be high, reliable information will still be needed on longer-term safety and duration of protection.