The term “herd immunity” has been front and center in the news in recent weeks. So what is herd immunity?
Herd immunity is a concept in epidemiology that describes how people can collectively be protected from infection if a specified amount of the population has immunity to a disease, which provides indirect protection to those who are not immune to the disease.
Herd immunity is achieved in one of two ways: A sufficient number of people become infected, or through vaccination of a high percentage of the population.
Herd immunity is achieved in one of two ways: A sufficient number of people become infected, or through vaccination of a high percentage of the population.
Herd immunity through infection has been touted as a way to end the pandemic. But consider how the term “Herd Immunity” originated. “Herd immunity” emerged from veterinary epidemiology, involving economic reasons of whether or not animals die for the overall health of a herd.
The idea is to protect those most at risk of serious illness and death while developing herd immunity among the rest of the population.
To begin with, no pandemic has ever been contained by purposely allowing the disease to spread unabated in the hope that people will develop immunity.
Scientists estimate that between 50 and 70 percent of the U.S. population would need to be immune to achieve herd immunity.
We should be extremely cautious when applying the concept of herd immunity to humans when dealing with a deadly disease like COVID-19. It is an equation that does not factor in the death and suffering of human lives.
What happened in the city of Manaus, Brazil gives a clue to the price in human lives the virus extracts when left unchecked. an estimated 66 percent of the population was infected and 1 in 500 people died. Moreover, the number of cases is rising again, suggesting herd immunity was never achieved.
Sweden, which is held up as an example of an effective herd immunity strategy, is in reality, not a successful model. The death rate in Sweden has been ten times that of its neighboring countries.
The proponents of herd immunity through infection argue that there would not be this sort of uncontrolled transmission. They believe that people under 65 should not be worried.
Hower this a specious and dangerous argument. Letting the virus remain unchecked in young adults would lead to infections and deaths in older people. Furthermore, many people under the age of 65 in the U.S. have underlying health conditions. This would lead to an enormous death toll.
Using the lower figure of 50 percent and using extrapolation of the number of cases versus the number of deaths as of October 29, 2020, this puts the number of deaths at a staggering 3.8 million people. The number of deaths is only part of the equation. The number of severely ill patients and patients with lifelong debilitating symptoms would be many more times that.
This would collapse the healthcare system and the economy.
Dr. Nahid Bhadelia, who directs the Special Pathogens Unit at Boston Medical Center, said: “It’s unlikely we can achieve natural herd immunity without completely using up physical and human resources.”
Herd immunity through natural infection is not a viable option according to Kristian Andersen, an immunologist at the Scripps Research Institute in La Jolla, California. “We have never successfully been able to do it before, and it will lead to unacceptable and unnecessary untold human death and suffering.”
Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security in Baltimore, states that scientists can only estimate herd immunity thresholds. Herd immunity can only be accurately ascertained by analyzing the data years after the pandemic, she says.
The final reason that herd community may be a myth with CoVID-19 is that there is still much to be learned about the body’s response to the novel pathogen. Researchers can measure antibody labels, but it is not clear how the immunity lasts and if antibodies alone are responsible for continued immunity. Recent studies show that immunity may only last three to five months. The severity of the illness seems to determine the level of antibodies produced.
There is an increasing number of reports that people are being reinfected. According to Anderson, it is not known how frequently these reinfections occur and whether they result in less serious or more serious illnesses.
“If the people who are infected become susceptible again in a year, then basically you’ll never reach herd immunity” through natural transmission, said Rivers.
It is understandable that people are tired and frustrated with the preventive measures in place. However, until a vaccine is available, the only sane, humane approach is to use the existing tools to control the spread of the virus.
