Fauci: Herd immunity could require 90 percent of country to be vaccinated

Achieving herd immunity against the coronavirus could require as much as 90 percent of the population to be vaccinated, Anthony Fauci said in an interview published Thursday.

Fauci, the country’s top infectious diseases expert, acknowledged in the New York Times interview that he has been incrementally raising his estimate of herd immunity numbers.

Fauci said he has been increasing the estimates in his public pronouncements because he thinks Americans are now able to handle the message that getting back to normal may take longer than anticipated, and fewer Americans are reporting being skeptical of taking a vaccine.

“When polls said only about half of all Americans would take a vaccine, I was saying herd immunity would take 70 to 75 percent,” Fauci told the Times. “Then, when newer surveys said 60 percent or more would take it, I thought, ‘I can nudge this up a bit,’ so I went to 80, 85.”

The Times noted that about a month ago, Fauci began saying herd immunity would take “70, 75 percent” of Americans being vaccinated. 

Last week, in an interview with CNBC News, Fauci estimated “between 75 and 80, 85 percent of the population.”

At that level of vaccination, Fauci said, “we would develop a umbrella of immunity. That would be able to protect, even the vulnerables, who have not been vaccinated, or those in which the vaccine has not been effective.”

The more infectious a disease is, the higher the rate of vaccination is required to reach a threshold of herd immunity. For example, measles, thought to be the most infectious disease in the world, needs a herd immunity of at least 90 percent.

Fauci said experts don’t really know for sure the level of vaccinations needed for herd immunity, but the initial estimates of 60 to 70 percent were based on early data.

“We need to have some humility here,” Fauci said in the interview. “We really don’t know what the real number is. I think the real range is somewhere between 70 to 90 percent. But, I’m not going to say 90 percent.”

Fauci’s comments come as data from the Centers for Disease Control and Prevention (CDC) show just over 1 million Americans have received the first of two vaccine doses against the coronavirus, and Trump administration officials admit they are unlikely to reach their goal of giving 20 million Americans the first dose by the end of year. 

More than 327,000 people in America have died from the virus, according to Johns Hopkins University estimates, and a new CDC “ensemble” forecast for the next four weeks predicts a total of 378,000 to 419,000 COVID-19 deaths by Jan. 16.

On Wednesday, more than 3,000 people died for the second consecutive day, according to the Johns  Hopkins data. 

Still, the Transportation Security Administration on Wednesday recorded 1,191,123 travelers passing through airport checkpoints, the most of any day since the pandemic began in March.