Scientists around the world are racing to develop a safe and effective vaccine against the novel coronavirus, but some people propose letting the virus infect everyone until we have herd immunity.
At first glance, letting the virus burn through the country, unchecked, until there are no more people for it to infect sounds like an interesting idea. No masks, people could again congregate in large groups and children could all go back to school.
Back in March even President Trump admitted he’d considered it.
“We had a lot of people who were saying maybe we shouldn’t do anything,” said Trump on March 29 in the Rose Garden. “Just ride it. Ride it like a cowboy. Just ride that sucker on through.”
But achieving what scientists call herd immunity without a vaccine could have an incalculable cost.
What exactly is herd immunity — which is also called community immunity?
Dr. Joanne Turner is Vice President for Research at Texas Biomedical Research Institute and Executive Director of the Vaccine Development Center of San Antonio. She likened it to defending yourself against zombies.
“If there's a zombie apocalypse and we haven't heard about it yet, then obviously all of us could get eaten by a zombie, and that's the pandemic beginning,” Turner said.
When no one has any natural immunity to a novel virus we’re all vulnerable. However, Turner said, over time, you learn how to protect yourself.
“Once you know the zombies out there, you would put a big fence up around your house or your community to stop them, right. And then nobody's getting eaten by a zombie.”
That fence is your community immunity. If the fence is well-built, everyone behind it is protected, even those who can’t defend themselves from an undead onslaught, like the little babies and the older folks and those who can’t fight or run very well. They’re all protected. They share in the community’s immunity. That’s akin to the community immunity that can be achieved by a vaccine. Those who can’t get one, like babies and people who are fighting cancer, are protected by everyone else who does get vaccines.
But, Turner said, that all depends on enough people getting vaccinated.
“One hole in that fence, which is that one person that didn't vaccinate, your zombies coming in, and then you're going to get eaten by a zombie,” Turner said.
What’s the alternative to community immunity achieved by vaccination? Natural herd immunity. Just ride it on through, as the president said.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and member of the nation's Coronavirus Task Force, shared his thoughts about this recently on Instagram Live with actor Matthew McConaughey. They’re grim.
“If you look at the United States of America, with our epidemic of obesity as it were, with the number of people with hypertension, with the number of people who have diabetes..If everyone got infected, the death toll would be enormous, and totally unacceptable,” Fauci told McConaughey. “And that’s the reason why we are against saying, ‘Let it fly. Let everybody get infected and we’ll be fine.’ That’s a bad idea,” Fauci added.
Experts don’t know for sure how many people would have to be infected with this disease to achieve community immunity. There are several factors to consider. Most say somewhere between 60 and 80%.
The population of the United States is about 330 million people. Choosing a percentage roughly in the middle, 70%, that means more than 230 million Americans would have to be infected for community immunity to take hold.
If 230 million Americans got infected with this coronavirus, several million people would likely die. Many millions more could have lifelong complications.
Additionally, there’s no guarantee that even after all of that sickness and death, natural herd immunity is even possible with this disease.
The apparent reinfection of a man in Hong Kong highlights the uncertainty that exists around how long a person who’s been infected with this coronavirus might be protected from reinfection. The man, who had COVID-19 in March, tested positive for a genetically different strain of the virus in August. That suggests that, for some, immunity might only last for a few months, meaning natural herd immunity is likely not an achievable goal.
Turner said that’s why developing a safe and effective vaccine is so important. She said this virus can be vicious, and while some populations — like the ones Fauci mentioned — are at increased risk for serious disease, anyone, of any age, can get serious COVID.
“Am I willing to take that risk by going out and saying, sure, we should all get it? If I'm the one, or someone close to me is the one, that ends up getting chronic long term disease or dying from it. I think we can't take that risk personally,” said Turner.
If enough people don’t get a vaccine, Turner mused, there is a hole in our fence, and the zombies can, and will, get through.
Learn much more about vaccines and the science and medicine around COVID-19 with Texas Public Radio’s Petrie Dish podcast. Listen and subscribe on Apple Podcasts, Spotify, or wherever you hear your favorite shows.
Bonnie Petrie can be reached at Bonnie@TPR.org and on Twitter at @kbonniepetrie.
