Herd immunity through COVID-19 vaccinations won't be achieved until at least the spring of 2021, a health official said Dec. 16.
Herd immunity "will happen when 70 or 80 percent of the American people have immunity against COVID," Adm. Brett Giroir, President Donald Trump's testing czar, said on CNN's "New Day."
"That's when you really see the pandemic dissipate. And it will go away, we will end the pandemic," he said.
The initial tranches of vaccines will be directed toward "immunizing for impact," according to Giroir. Those in long-term care facilities will be among the first groups to be immunized, in hopes of quickly preventing more COVID-19 outbreaks in nursing homes, he said, adding that this would lower the mortality rate and the hospitalization rate dramatically.
The impact will be seen "almost immediately," Giroir said, "but herd immunity, when the pandemic really ends and goes away, that's not until the late spring, early summer" of 2021.
Americans should continue adhering to public health guidance such as staying six feet away from non-household members and wearing masks, the official said, warning that not doing so would lead to "thousands of more casualties in this country that we can avoid."
Herd immunity, also known as community immunity, is when a certain amount of people have become immune to a disease either through vaccination or previously having had the disease.
"That means even people who can’t get vaccinated will have some protection from getting sick. And if a person does get sick, there’s less chance of an outbreak because it’s harder for the disease to spread. Eventually, the disease becomes rare—and sometimes, it’s wiped out altogether," the Department of Health and Human Services says on its website.
A number of people are already immune to COVID-19 because they contracted the illness in recent months, though the period of immunity is not yet known.
Dr. Anthony Fauci, the longtime director of the National Institute of Allergy and Infectious Diseases, said the goal is to vaccinate people as quickly as possible until herd immunity is achieved.
Fauci said that this will require getting 75 to 80 percent of the population vaccinated.
Health officials say approximately 20 million Americans will receive the vaccine this month, with another 30 million being vaccinated in January 2021.