What is herd immunity, and what would it mean at Miami?

More than 1,500 Miami students have tested positive for COVID-19 since Aug. 17 — nearly 10% of the total student population. As infections continue to rise, many students have joked about getting infected intentionally in the name of herd immunity. But for the health professionals informing Miami’s response to the pandemic, this trend has dangerous implications for the Oxford community.

Herd immunity occurs when a large majority of a population becomes resistant to an infectious disease, significantly slowing the disease’s spread. Resistance can come in the form of a vaccination or antibodies from a previous infection.

Generally, anywhere from 80 to 95% of a population needs to be resistant to a disease to reach herd immunity. The exact percentage changes from disease to disease based on factors like rate of infection and how long immunity lasts.

Jennifer Bailer, health commissioner for Butler County, said this statistic can be hard to nail down for new diseases like COVID-19.

“Immunity to COVID by having had the disease seems to last only about 3 months,” Bailer wrote in an email to The Miami Student. “Getting an entire population immune is fleeting and needs to be re-established over and over again. Indeed, it may never be adequately established via disease only and would require vaccination in addition to disease.”

Eileen Bridge, an associate professor of microbiology at Miami, explained that any potential vaccine for the coronavirus will first have to make it through Phase 3 testing for safety and effectiveness before it can be approved by the FDA.

“Normally, this is a process of years rather than months,” Bridge said. “I don’t necessarily think that fast-tracking the vaccine is wrong, but I do think it needs to be done cautiously.”

For Grace Connors, a sophomore public health major, whether or not to take the vaccine is an open question.

“That’s a very fast turnaround,” Connors said. “Vaccines are known to have some complications from time to time. But also from the perspective of looking out for everyone else, I would feel rather inclined to get it, especially if there’s enough push toward the concept that it would get the nation back to some sort of normalcy or reduce deaths and cases.”

Despite potential complications associated with the eventual COVID-19 vaccine, Bridge and Bailer agree that intentionally getting infected with COVID-19 for temporary immunity is unnecessarily dangerous for students.

“While most young adults get mild cases, intentionally spreading or getting a disease can be dangerous to some members of the population,” Bailer wrote. “A ‘herd’ will include vulnerable individuals who could become seriously ill and potentially die from COVID.”

In early September, Jamain Stephens, a senior at California University of Pennsylvania, died following complications related to COVID-19, the first college football player to succumb to the virus.

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On Sept. 28, sophomore Chad Dorrill of Appalachian State University passed away less than a month after testing positive for the virus.

The CDC reports that 18-29 year olds are 30 times less likely to die from COVID-19 than 50-64 year olds. Despite this, hospitalization is only four times less. College students may have a relatively low risk of death from COVID, but not everyone who gets infected will be asymptomatic. The more students who get infected, the greater the risk that some will have a severe reaction to the virus.

“[Students] don’t know if it’s going to be one in a hundred people their age who get very sick, one in a thousand or one in ten thousand,” Bridge said. “They just don’t know. And I think purposefully intending to get sick to get it over with, that puts you at serious risk.”

Although Connors said she is being careful herself, she has noticed some of her peers don’t seem to care about the potential risks of a COVID-19 infection.

“I’ve heard people like, ‘I don’t care,’ and they’ll just go around hugging people,” Connors said. “One girl who I know was doing that got COVID.”

Even if students could guarantee that they would have no side effects from an infection, a high number of student infections puts the wider Oxford community in danger. From classrooms to uptown restaurants to Walmart, students have plenty of opportunity to interact with higher-risk individuals. Bridge stressed that student behavior has a direct impact on the Oxford community, as well.

“The point is that students don’t live in a bubble,” Bridge said. “They do go out in the community. And as long as they’re doing that, they are potentially bringing the disease to people in the population that may not have the same ability to withstand the infection that they do.”

Until a vaccine is publicly available and widely accepted, Bridge said there is no easy fix.

“Achieving herd immunity by vaccines is a great thing,” she said. “Trying to achieve herd immunity by having 95% of the population become infected with COVID-19 is going to put a significant number of those of us who are older and may have preexisting conditions at risk.”

scottsr2@miamioh.edu