Could herd immunity help stop spread of coronavirus?

Posted at 6:43 PM, May 19, 2020
and last updated 2020-05-19 18:55:17-04

Some people across the country are pushing for a new strategy to fight coronavirus - letting the virus run its course so we can build herd immunity.

"[Herd immunity] is this concept of, if a large proportion of the population has some sort of immunity, then there's a protective effect for the rest of the population that doesn't already have that immunity," said Dr. Carrie Dolan, Assistant Professor of Health Sciences at William and Mary.

To achieve herd immunity with COVID-19, Dr. Dolan says research indicates about 70 to 80 percent of the population would need to be immune to the virus to protect the remaining 20 to 30 percent.

Right now we're nowhere near those numbers.

"Recent research estimates about 2 to 3 percent of the U.S. population has had an immunity response to COVID- 19. It could be higher in some places like New York City, but 2 to 3 percent is what we're generally comfortable with," said Dr. Dolan.

That means establishing herd immunity would not happen anytime soon.

Dr. Dolan estimates a year or two, but says we also need to think about the consequences of getting to that point.

"If we have to get all the way up to that threshold of 70 to 80 percent, we've already had about 90,000 deaths just to get to the two to three percent, and so we're talking hundreds of thousands of deaths in order to reach the threshold just based on community-based spread of the disease," said Dr. Dolan.

Dr. Dolan says people have also been asking her about 'COVID parties,' similar to chickenpox parties held in the 80s in which people try to intentionally get infected with a virus.

Dr. Dolan says there are several problems with this idea. One is that COVID-19 is at least 100 times more deadly than the chickenpox.

There's also a lot we still don't know about the virus.

"We don't know how much viral load people need in order to get an immunological response, and then we don't know how long that lasts. So even if you infect yourself, we don't know how long it's gonna last, and you could end up getting it again in the future. The research just isn't out there yet," said Dr. Dolan, "And then the other thing we don't know is how that virus is going to respond in individuals."

Dr. Dolan says a safer way to reach herd immunity is through vaccinations.

Although that's still in the works, protective measures like hand washing and social distancing can buy time until that happens.

In the meantime, Dr. Dolan says as businesses start to reopen, it's a good idea for people to think about their risk tolerance on a scale of one to five.

"One being that you're in complete lock down. That you'd have no contact with people. And five, you're ready to get on a plane and fly to the Maldives," said Dr. Dolan, "And we are all going to be on different levels of that spectrum at different times, and I think it's important to be able to start a dialogue around communicating where we are so that people will be able to understand our risk factors and how we're viewing where we are within the pandemic."