A: Herd immunity, or community immunity, is defined by the Center for Disease Control (https://www.cdc.gov/vaccines/terms/glossary.html) 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. Even individuals not vaccinated (such as newborns and those with chronic illnesses) are offered some protection because the disease has little opportunity to spread within the community. Also known as herd immunity.” Essentially herd immunity is what happens when a disease runs out of people that are susceptible.
However, at this point in the pandemic response, it is challenging to assume anything about COVID-19, because the world is learning more about it every day. Long-term effects of a COVID-19 infection are still mostly unknown. Additionally, according to Mayo Clinic, (https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/herd-immunity-and-coronavirus/art-20486808) it is not clear if infection with the COVID-19 virus means a person is immune to future infections. Recently, stories (https://www.bbc.com/news/health-54512034 and https://www.npr.org/sections/coronavirus-live-updates/2020/10/12/922980490/scientists-confirm-nevada-man-was-infected-twice-with-coronavirus) have been published reporting about individuals becoming infected with COVID-19 more than once. If it is possible for people to be infected multiple times with COVID-19, herd immunity may not be possible long-term due to availability of people that are susceptible.
Some in the medical community are against the notion of herd immunity because it eliminates prevention of a disease. Dr. Christopher J.L. Murray, the director for Institute for Health Metrics and Evaluation and a lead COVID-19 modeler, described herd immunity: “As a strategy, it simply means letting an awful lot of people die because we let the virus spread through the whole population, and it’s not really a strategy at all.” (http://www.healthdata.org/video/covid-19-myth-herd-immunity?fbclid=IwAR3rxptFGmLWdIz99WLexoRgjaGCOQ2S1_90ThUcaYfQaeIeZYsbaQ9llOg)
According to an article in The Lancet (https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31924-3/fulltext), “Studies in June and July cast doubt on prospects for herd immunity: despite months of exposure, antibody surveys found a low seroprevalence, less than 10%, in cities in Spain and Switzerland. Commentators in The Lancet concluded that ‘in light of these findings, any proposed approach to achieve herd immunity through natural infection is not only highly unethical, but also unachievable.’”
In a recent Associated Press article (https://bismarcktribune.com/news/national/un-warns-against-pursuing-herd-immunity-to-stop-coronavirus/article_201e45b2-9865-586a-8b45-dbd1cbb31712.html) the head of the World Health Organization warned against the idea that herd immunity might be a realistic strategy to stop the pandemic, dismissing such proposals as “simply unethical.”
At a media briefing Monday, WHO director, General Tedros Adhanom Ghebreyesus said health officials typically aim to achieve herd immunity by vaccination. Tedros noted that to obtain herd immunity from a highly infectious disease, such as measles, for example, about 95% of the population much be immunized.
“Herd immunity is achieved by protecting people from a virus, not by exposing them to it,” he said.
In the absence of a COVID-19 vaccine, to reduce the risk of infection individuals must follow the universal precautions that have been in place through much of the pandemic response:
- Avoid large events and mass gatherings.
- Avoid close contact (within 6 feet) with anyone who is sick or has COVID-19 symptoms.
- Stay home and/or keep distance between yourself and others if COVID-19 is spreading in your community.
- If it is difficult to avoid close contact with other individuals, wear a face covering.
- Wash your hands often with soap and water for at least 20 seconds. If soap and water is not available, use an alcohol-based hand sanitizer that contains at least 60% alcohol.
- Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Throw away the used tissue.
- Avoid touching your T-Zone (eyes, nose, mouth).
- Clean and disinfect commonly used surfaces (doorknobs, light switches, counters, electronics, etc.) frequently.