U.S. scientists are skeptical of a one-shot regimen for Pfizer Inc and Moderna Inc COVID-19 vaccines, saying there isn't enough evidence that a single dose provides long-term protection, the Wall Street Journal reported.
"It is essential that these vaccines be used as authorized by FDA in order to prevent Covid-19 and related hospitalizations and death," Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, told the Journal.