Erin Bromage, a professor of biology at the University of Massachusetts Dartmouth, told CNN’s Brianna Keilar that it was always known that breakthrough Covid-19 cases would happen in vaccinated people, but that they’ve caught people by surprise.
“We know that there are breakthrough cases and we knew that they were going to happen right from the start when they released the Phase 3 data that said that the vaccines were roughly 95% effective,” Bromage said on New Day Wednesday when asked about breakthrough infections in vaccinated people.
“Seeing them now is really not, you know, unsurprising in the greater scheme of the pandemic,” he said. “It’s just that people have been caught by surprise.”
The phase 3 vaccine data tested for efficacy of the vaccines among symptomatic cases – individuals who were infected and exhibited symptoms – not overall infection.
People who are fully vaccinated and who have changed their behavior, doing things like going to restaurants, bars and clubs have been caught by surprise, he said, because while their personal risk for developing symptoms has decreased, the activities of gathering in closed, confined spaces are still higher risk activities. “If you’re indoors in a church or in a restaurant and it’s not a big open space, the air being shared by a lot of people around you, then you’re actually putting yourself at higher risk for infection,” said Bromage. “Now, high risk for infection for a vaccinated person probably doesn’t matter as much because we know it doesn’t lead to severe disease,” he added.