We’re eight months into the COVID-19 pandemic. In the United States, cases have risen to record levels and officially hit over 100,000 confirmed coronavirus cases on November 4. More than 230,000 Americans are confirmed to have died from COVID-19 to date, with thousands of additional deaths attributable to the virus but not counted in the official statistics. Even in the face of these numbers, we’re still lacking strong federal leadership and a unified national response plan to the pandemic.
Recently, several scientists and politicians have suggested the harmful and controversial idea that perhaps it might be better to aim for “herd immunity.” In my view (and that of many other epidemiologists), this would essentially mean letting the virus burn through less vulnerable segments of the population rather than trying to prevent widespread infection via interventions including mask use and social distancing. One group of scientists in particular outlined this strategy in October, referring to it as “focused protection” in a statement called the Great Barrington Declaration. As they describe it, this approach would reduce direct harm from the virus and also inadvertent “social harm” from social distancing and lockdowns that have led to closing businesses and schools. One of their claims, which has received fervent backlash from public health experts at large, is that “the most compassionate approach that balances the risks and benefits of reaching herd immunity, is to allow those who are at minimal risk of death to live their lives normally to build up immunity to the virus through natural infection, while better protecting those who are at highest risk.” A Trump administration pandemic adviser, neuroradiologist Scott Atlas, M.D., who doesn’t have a background or specialty in infectious disease, has also embraced this strategy.
There is nothing that most of us would like more than having some semblance of normality. So why have most scientists in the field dismissed this idea of coronavirus “herd immunity” as inadequate for containing the virus and dangerous to us all? I spoke with four scientists for their thoughts.
First: What exactly does herd immunity mean?
“Viruses require a host to replicate,” Columbia University virologist Angela Rasmussen, Ph.D., tells SELF. “Herd immunity is when enough people in a population are immune to a given virus that the virus can’t spread any more within that population because it can’t find a susceptible host.” Deepti Gurdasani, MBBS, M.D., MPhil, Ph.D., an epidemiologist at Queen Mary University in London, notes that herd immunity additionally protects those who are not immune, like babies who can’t receive certain vaccinations yet or the minority of people who can’t receive certain vaccinations due to medical issues like a compromised immune system. “The likelihood of them coming into contact with an infected person becomes much lower,” Dr. Gurdasani explains.
There are a few different ways to achieve herd immunity with infectious diseases. One is through widespread vaccination in a community. Vaccines stimulate people’s immune systems in a way that protects them from getting an infection and often makes the infection less likely to be severe if they do wind up catching it. When enough people in a community get vaccinated to protect against a disease, that leads to herd immunity for that population. Unfortunately, we don’t yet have a COVID-19 vaccine to help us achieve this goal.
A far less ideal route to herd immunity, depending on the disease in question, is if enough people in a community get the illness and develop antibodies that prevent the same infection in the future, even temporarily. This isn’t a guarantee with every infectious disease. For instance, there’s still a lot we don’t know about coronavirus antibodies and immunity—more on that in a bit.