It's not an option for handling the pandemic, says the World Health Organization.
By Claire Gillespie and Updated October 14, 2020 Advertisement ellipsis More A concept bandied about early in the coronavirus pandemic, something called "herd immunity," has surfaced again.
President Trump referenced the idea during an last month, insisting the virus would eventually go away as people develop "a herd mentality."
(Okay, he misspoke, but we think we know what he meant.)
Then, during a on the nation's pandemic response, Senator Rand Paul (R-Kentucky) tussled with Anthony Fauci, MD, the nation's leading infectious disease expert, over whether "community immunity" is responsible for New York City's currently low infection rate.
"They’re no longer having the pandemic because they have enough immunity in New York City to actually stop it," asserted the state's junior senator.
Dr. Fauci, a member of the White House Coronavirus Task Force, forcefully pushed back, arguing that New York's low positivity rate reflects its adherence to task force recommendations, including the use of masks and social distancing, not herd immunity.
Now the head of the World Health Organization (WHO) is weighing in with a strong rebuke.
On Monday, Director-General Tedros Adhanom Ghebreyesus said reaching herd immunity by letting the virus spread throughout the population would be "simply unethical," resulting in unnecessary suffering and death.
"Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak, let alone a pandemic.
It is scientifically and ethically problematic," he said.
So what is herd immunity, anyway, and how does it relate to COVID-19?
RELATED: Herd immunity (also known as community immunity) is defined by the (CDC) as “a situation in which a sufficient proportion of a population is immune to an infectious disease (through vaccination and/or prior illness) to make its spread from person to person unlikely.” In other words, where herd immunity exists—when lots of people in an area are vaccinated or have already been infected with a disease—fewer people get sick and fewer germs are able to spread from person to person.
RELATED: The theory is that when someone gets vaccinated, it’s not only that person who is protected from infection but others too, because that individual cannot transmit the disease in the community.
In that way, herd immunity protects people who cannot be vaccinated, people whose immune systems aren’t strong enough and are therefore the most vulnerable to serious illness.
A late 1980s measles outbreak among preschool-age children in the US serves as an example of herd immunity via vaccination.
who examined the association between incidence of measles and immunization among preschool-age children concluded that immunizing about 80% of the population may be enough to stop sustained measles outbreaks in an urban community.
In the context of COVID-19, developing herd immunity would mean protecting the most vulnerable citizens while letting most everyone else catch, and hopefully recover from, the virus.
RELATED: Allowing people to contract COVID-19—Is that a good idea?
Sweden famously eschewed a lockdown approach in favor of allowing people to take personal responsibility for their health.
But as the authors of a recent commentary published by the point out, "herd immunity is nowhere in sight."
Rates of infection, hospitalization, and death per million people are much higher than in neighboring Scandinavian countries, they report.
WHO's Ghebreyesus makes it clear that herd immunity is something that's achieved when a certain threshold of vaccination is reached against a virus in a population.
"In other words, herd immunity is achieved by protecting people from a virus, not by exposing them to it," he said.