An estimated one-quarter of Americans will opt out of coronavirus vaccinations this year, the non-partisan research organization said in a report. If activities involving personal contact surpass 70% of pre-pandemic levels, an additional 4.6 million people could catch the virus this year.

“If all eligible US residents are vaccinated in 2021, we project that the pandemic will effectively be over by the fall,” researchers Alex Arnon and John Ricco wrote in the report. “Differences in the vaccine take-up rate lead to large differences in the state of the economy at the end of 2021.”

Universal vaccination would mean 8.3 million fewer virus cases this year, and would trigger an economic boom according to the projections, with fourth-quarter GDP growth 2 percentage points faster and an extra 2.6 million jobs created by December.