Good Question: Have we reached herd immunity with COVID-19?

ROCHESTER, N.Y. — Have we reached herd immunity for COVID-19? Three years ago, at the onset of the pandemic, there was a lot of talk about “herd immunity.” Some experts thought that once we reached it, we’d all be better protected against the covid virus.

Now, three years and several variants later, we’re learning that “herd immunity” to COVID might not even apply. Before the COVID virus began mutating, you might remember hearing this.

“When you get the majority, the overwhelming majority of the population vaccinated so you can get that umbrella of herd immunity,” said Dr. Anthony Fauci, former director of the National Institute of Allergy and Infectious Diseases.

That means a majority of people are immune to a disease either through vaccination or previous infection. A viewer named Bob asks: “Did we ever reach herd immunity?” It’s a simple question with a not-so-simple answer.

“It depends on how much the virus changes. …What we’ve learned since the beginning of the pandemic is that herd immunity in the traditional sense may not apply to COVID,” said Dr. Emil Lesho, an infectious disease expert for Rochester Regional Health.

Back in 2020, the original benchmark for reaching herd immunity was in the range of 70-80% of the population becoming immune. but that was before we saw variants like Omicron and Delta.

“As it goes through all these generations of mutations and variants, it looks like it gets a little closer to behaving like a head cold virus,” Lesho said.

You don’t hear about “herd immunity” in relation to the common cold or the flu because there are so many different strains, and they change from year to year and with COVID.

“It’s changing fairly rapidly and we may never get to true herd immunity unless it stops changing so much,” Lesho said.

Herd immunity might not apply to covid anymore but it is critical in pathogens that don’t mutate. One example Lesho gave was measles. Without herd immunity to measles, we could see breakthrough cases that would have a serious effect on people who don’t respond well to infections or vaccines.

If you have a good question, send it to us at goodquestion@whec.com