Expert Predicts Herd Immunity by May, but Certain Roadblocks Could Prevent It

In a new report about the status of COVID-19 in Arizona, Joe Gerald, an associate professor in the University of Arizona's Mel and Enid Zuckerman College of Public Health, said that as case positivity continues to decline and the number of vaccine doses continues to rise, Arizona could see herd immunity by late April or early May, adding that herd immunity is based on several factors including "vaccine efficacy, viral transmissible and natural immunity."