Are we there yet? What happens if the U.S. can't reach herd immunity.

Without herd immunity, the country will see localized surges. But even if we don't get there, experts say there's still reason for hope.

Herd immunity is often seen as the end game of the COVID-19 pandemic. This threshold is reached when the virus cannot easily spread because most people have built up immunity through vaccination or natural infection. Then, “the virus just can’t find anyone to infect,” says Monica Gandhi, a professor of medicine and infectious diseases expert at the University of California, San Francisco, and the threat fades.

Experts estimate that we’ll reach herd immunity for COVID-19 when 65 to 80 percent of the population is vaccinated—a number that seemed within reach in the U.S. once highly effective vaccines started being administered. But after peaking at a seven-day average of more than three million doses in early April, the rate declined,

Unlock this story for free
Create an account to read the full story and get unlimited access to hundreds of Nat Geo articles.

Unlock this story for free

Want the full story? Sign up to keep reading and unlock hundreds of Nat Geo articles for free.
Already have an account?
SIGN IN

Read This Next

What bacteria lurk in your city? Consult the bees.
Is melatonin giving you nightmares?
Why are these orcas killing sharks and removing their livers?

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet