Colorado Infection Prevention Expert Calls Johns Hopkins Professor's Herd Immunity Prediction 'A Little Overly Optimistic'

DENVER (CBS4) – According to new data from Johns Hopkins University professor Dr. Marty Makary, COVID-19 cases are down 77% nationally over the past six weeks. In a recent opinion article, Makary says he expects Americans to reach herd immunity by April. He elaborates, "There is reason to think the country is racing toward an extremely low level of infection. As more people have been infected, most of whom have mild or no symptoms, there are fewer Americans left to be infected." CBS4's Mekialaya White asked a local expert to weigh in on the topic.

Dr. Michelle Barron, Senior Medical Director of Infection Prevention and Control at UCHealth, provided expertise.

"I don't want to be the one to dampen enthusiasm because obviously if we got to herd immunity by April that would be amazing," said Barron. "But I think it's a little overly optimistic, I think it's a little premature to say what we'll have it by that timeframe."

Barron first explained the concept of herd immunity.

"The idea behind it is that everybody has the ability to have an immune response against the infection, so that they either don't get sick or they get so mildly sick that they don't have an impact from it."

Barron says the only way we'll probably achieve herd immunity is by getting people vaccinated, as opposed to building up a resistance naturally.

"With these variants coming into play in the next month or whenever they decide, they may be different enough from the initial infection that your immune system doesn't recognize them at all. Whereas the vaccine has a component that is similar enough across all these strains so far, the vaccine will protect you. We know with the natural infection, those antibody responses will typically start to fall down to a level when they're not considered effective. So you may have been infected a year ago, but now it really means nothing," said Barron.

"I would encourage everybody to get a vaccine. If you're still having doubts, talk to a friend, talk to a provider, talk to someone you trust, to make sure you understand fully what the potential benefit for this is."

She added, "We had one of those milestones that is really tragic -- 500,000 deaths in the U.S. That's a huge number of people that are lost. And we will never recover from those things."

Barron predicts that we could possibly have herd immunity by late summer or early fall.