Some experts say the messaging around the number of shots needed for vaccination has been confusing, in part because no one anticipated how the virus would evolve. When vaccines were first rolled out in December 2020, officials made a “communications blunder” when they said vaccinations would be “two shots, and done,” [said] Andrew Noymer, [associate professor of public health], an epidemiologist at the University of California, Irvine.
Booster shots in U.S. have strongly protected against severe disease from omicron variant, CDC studies show
The Washington Post, Jan. 21, 2022
January 21, 2022