COVID-19 and herd immunity, your questions answered
INDIANAPOLIS (WISH) — Herd immunity is essential to stopping the spread of the coronavirus.
But what exactly is it and when will we get there?
News 8 spoke with Libby Richards, an associate professor at the Purdue University School of Nursing, to answer your questions.
Q: What is herd immunity and how will it protect the public from COVID-19?
Richards: Herd immunity occurs when a large proportion of a population (community) becomes immune to a disease. Herd immunity makes it difficult for that disease to spread from person to person. Because of this reduced ability to spread, the whole community gets protected.
Q: Herd immunity can be achieved by natural infection or vaccination. Which one is better and why?
Richards: Herd immunity by vaccination is the preferred method. Vaccines provide immunity without causing disease. Natural infection is much more unpredictable and can result in serious complications or even death. Also, it isn’t clear yet that infection with COVID-19 results in subsequent immunity.
Q: Harvard University researchers say we need 60% to 70% of the U.S. population to be immune to the coronavirus in order to develop herd immunity. How close are we to that?
Richards: We are not even close. Seventy percent of the U.S. population is more than 230 million people, according to the 2018 Census. The U.S.is currently reporting just under 5 million confirmed cases.
Q: Researchers are concerned not enough people will get the vaccination right away because they don’t want to be guinea pigs and be at risk of possible consequences. Should this be a concern?
Richards: Low vaccine rates are always a concern and a major public health issue. Only about 49% of Americans got the flu vaccine last year which is way too low. Vaccine testing and safety approval is a strict three phase process. Phase 1 tests vaccine safety in a limited number of people and tests vaccine dosage. Phase 2 is an expanded safety study for various population characteristics such as age and health status. In Phase 3, the vaccine is tested in thousands of people for effectiveness and safety.
Currently two U.S. developed vaccines are in Phase 3 trials, each with at least 30,000 Americans enrolled. The Food and Drug Administration (FDA) is responsible for overseeing vaccine safety. Once a vaccine is FDA approved, it is ready for widespread use and should be received.
Q: Some people might not be healthy enough to get a vaccine. It could do more harm than good. Who are these people and will they have to continue to wear masks, isolate and socially distance? How will herd immunity help this population?
Richards: It is currently more clear who should be top priority to receive a vaccine – healthcare workers, older adults, residents of long-term care facilities, and those with chronic conditions (heart and lung disease, diabetes, cancers). It is less clear who will not be able to be vaccinated, but this population likely includes infants and those with allergies to vaccine derivatives. Herd immunity is essential to protect those who can’t receive a vaccine.
Q: When do you think we will achieve herd immunity?
Without a vaccine, I don’t think we will. Even with a vaccine, if people don’t become vaccinated, we don’t stand a chance. Without a high proportion of the population receiving a vaccine, we will continue to have large outbreaks of COVID-19 for years to come.
News 8’s medical reporter, Dr. Mary Elizabeth Gillis, D.Ed., is a classically trained medical physiologist and biobehavioral research scientist. She has been a health, medical and science reporter for over five years. Her work has been featured in national media outlets.