The nation is just beginning its coronavirus vaccination campaign, and already it sounds like herd immunity is getting harder to reach. The World Health Organization puts the population share that needs to have achieved resistance through having the virus or receiving a vaccination at 60% to 70%. Early on, Dr. Anthony Fauci said the same thing. But recently, he's been inching that goal up, the New York Times reports—and hedging. He suggested 70% to 75% last month, then "75, 80, 85%" last week. Fauci doesn't deny shifting the goal, partly based on increasing acceptance of the vaccines. "When polls said only about half of all Americans would take a vaccine, I was saying herd immunity would take 70 to 75%." he said. "Then, when newer surveys said 60% or more would take it, I thought, 'I can nudge this up a bit,’ so I went to 80, 85."
WHO's immunization director said the early goal probably was too low, but she won't give a revised figure. "We should say we just don’t know," Dr. Katherine O’Brien said. "And it won’t be a world or even national number. It will depend on what community you live in." Fauci agrees there's not a way to know exactly what's needed. But at 75% to 85%, "we would develop a umbrella of immunity," he said, per CNBC. "That would be able to protect, even the vulnerables, who have not been vaccinated, or those in which the vaccine has not been effective." Although he'd be happy with it higher, he said he doesn't want to set a goal so high it would discourage people. "I'm not going to say 90%." That's measles territory, and "I'd bet my house that Covid isn’t as contagious as measles," Fauci said. (Fauci celebrated this week.)