Do you really know what Herd Immunity means?
February 22nd marked the day America’s Covid-19 death toll reached 500,000 people. In January, Covid-19 passed heart disease, cancer, and other ailments to become the leading cause of death for Americans. The only hope America has to end the deaths of Americans from Covid-19 is herd immunity.
Herd immunity has become a buzzword through the months of the pandemic, thrown around on every morning talk show or article about Covid-19. But what does herd immunity really mean? And how can we achieve it in the United States?
What is herd immunity?
Herd immunity, also known as community immunity or herd protection, occurs when the vast majority of the population of a specific area is immune to a certain disease. Herd immunity will protect the entire group, even if some people are still high-risk. These high-risk individuals may include babies or people whose immune system is not strong enough to prevent them from getting sick.
How does herd immunity work?
If the majority of the population is immune to a disease, the virus can no longer be transmitted and will die out. For herd immunity to work effectively, 70-80% of the population must be immune to the disease. If 80% of the community is immune to the virus, 4 out of every 5 people who encounter the pathogen will not get sick or spread the disease.
How is herd immunity achieved?
Herd immunity can be achieved through several avenues. In some cases, it can occur naturally, but in others, a vaccine can be utilized to reach community immunity.
Depending on the lethality of a disease, it is possible for herd immunity to be reached naturally. This occurs after a large percent of the population has survived the illness and developed antibodies to fight off the disease. These antibodies will leave you immune for several months if you encounter the disease again.
Herd immunity can also be achieved with the help of a vaccine. The vaccine will teach your body to make protective antibodies against an illness without you getting the actual infection. The immunity provided by a vaccine lasts longer than naturally occurring immunity in most cases.
Covid Herd immunity?
Herd immunity is measured by the reproductive number, or R0, of a disease. The R0 determined the average number of people that a single person with the virus can infect if those people aren’t already immune.
For Covid-19, researchers think the R0 is between 2 and 3- meaning that one person has the ability to infect two or three other people. Based only on the reproductive number, 50-67% of the population would need to be resistant before herd immunity is achieved and infection rates start to go down.
When will the United States reach herd immunity?
For the United States to reach herd immunity, at least 70-80% of the population must be vaccinated. This number is higher than the R0 because of human nature and the propensity of Americans to congregate with some not wearing masks. Americans are spreading Covid-19 faster than expected and this changes when we reach herd immunity.
However, because of high fatality rates in high-risk communities, herd immunity achieved naturally is not a viable option for Covid-19 in America. Thankfully, if the vaccination rollouts reach the estimated 150 million doses by March- more than 3,000,000 shots per day, herd immunity may be reached by this summer.
There are several cities in the United States edging closer to reaching herd immunity, Los Angelos being one of them. 33-55% of the population of LA has already been infected by Covid-19. While cases are falling in LA giving proof of herd immunity beginning to work, unfortunately, over 12,000 people have died for this to occur.
Hurdles to Herd Immunity
Unfortunately, Americans are also facing many hurdles towards achieving herd immunity.
Vaccine Hesitancy: According to a recent AP-NORC survey, 32% of Americans say they “definitely or probably won’t get a Covid-19 vaccine.” If these Americans stick true to their word, herd immunity will never be reached in the United States. As the 70-80% immunity will not be achieved.
The Role of Children: Because children make up 22% of the American population, herd immunity likely cannot be achieved without them. This is problematic given that Covid-19 vaccines have not been approved for children.
Mistrust of Healthcare System: For many Black and Brown Americans, there is an inherent mistrust of the medical system which may root back to medical discrimination. This distrust is likely to feed into vaccine hesitancy as well.