Developing herd im-munity is heralded as one pathway to containing the coronavirus pandemic. What is herd immunity, how is it achieved and will it work to contain COVID-19, the disease resulting from the coronavirus?
“Those are the questions everyone wants the answers to,” said Kelli Heindel, MD, FAAFP, Medical Director of Primary Care for ThedaCare Physicians Clinically Inte-grated Network. “Because this coronavirus is so new – thus called the ‘novel coronavirus’ – the medical community does not have solid answers about herd immunity just yet.”
According to the Centers for Disease Control and Prevention (CDC), herd immunity is achieved when a large enough population group becomes immune to a disease, either by having the disease and developing antibodies or by being vaccinated against the disease. When that population group is large enough, the spread of the disease may be slowed because an infected person will likely come into contact only with people who are already immune rather than someone who is still susceptible.
However, herd immunity doesn’t work against every disease. “The more contagious a disease is, the greater is the proportion of the population that needs to be immune to the disease to stop its spread,” the CDC reports. The novel coronavirus is considered highly contagious.
“Because the coronavirus is so new, not much is known about how long antibodies to the virus may last in a person’s body and if having antibodies even protects against reinfection with the virus,” said Dr. Heindel. “If someone has antibodies present, that should not give the person a false sense of security. We do not want you to relax social distancing guidelines, and still recommend wearing a mask. Until we learn more, we want to help protect others, not assume that you’ve had the virus and cannot get it again or spread it to others.”
A recent study in China indicated that antibodies can disappear in two to three months.
According to the Mayo Clinic, “First, it isn’t yet clear if infection with the COVID-19 virus makes a person immune to a future infection. Research suggests that after infection with some coronaviruses, reinfection with the same virus is possible after a period of months or years.
Further research is needed to determine the protective effect of antibodies to the coronavirus in those who have been infected. Even if infection with the COVID-19 virus creates long-lasting immunity, a large number of people would have to become infected to reach the herd immunity threshold. Experts estimate that in the U.S., 70% of the population — more than 200 million people — would have to recover from COVID-19 to halt the epidemic.”
“There is still so much to be learned about COVID-19 at this point that relying on herd immunity to slow the pandemic in the United States at some point in the future is unrealistic,” said Dr. Heindel. “That’s why it is important that a vaccine be developed and that people continue to follow the recommended guidelines from health care professionals.”
She shared these recommendations to help prevent the spread of the virus:
Wear a face mask or covering in public.
Take part in social distancing, 6 feet from one another.
Avoid handshakes, hugs and kisses.
Wash hands often with soap and water for at least 20 seconds, or use a hand sanitizer that contains at least 60 percent alcohol.
Clean and disinfect common household surfaces.
Avoid people who are sick.
Stay away from others if you are sick.
Cover your mouth and nose when coughing or sneezing, using your arm or a tissue.
Avoid touching your eyes, nose, and mouth.
“We have a long way to go to control this virus,” explained Dr. Heindel. “Be careful and thoughtful about what you do and whom you interact with to reduce your exposure. Let’s do our best to protect ourselves and one another.”
