Why is this so crucial?
Herd immunity occurs when a large portion of a community (the herd) becomes immune to a disease, making the spread of disease from person to person unlikely. As a result, the whole community becomes protected — not just those who are immune.
Often, a percentage of the population must be capable of getting a disease in order for it to spread. This is called a threshold proportion. If the proportion of the population that is immune to the disease is greater than this threshold, the spread of the disease will decline. This is known as the herd immunity threshold.
What percentage of a community needs to be immune in order to achieve herd immunity? It varies from disease to disease. The more contagious a disease is, the greater the proportion of the population that needs to be immune to the disease to stop its spread.
- For example, the measles is a highly contagious illness. It's estimated that 94% of the population must be immune to interrupt the chain of transmission.
- Typically, herd immunity for the Coronavirus is/might be achieved when 70% to 90% of the population is immune through natural infection or vaccination. Some research goes so far with 50% immunization for the population.
How is this herd resistance achieved?
A vaccine for the virus that causes COVID-19 would be an ideal approach to achieving herd immunity. Vaccines create immunity without causing illness or resulting complications. Herd immunity makes it possible to protect the population from a disease, including those who can't be vaccinated, such as newborns or those who have compromised immune systems. Using the concept of herd immunity, vaccines have successfully controlled deadly contagious diseases such as smallpox, polio, diphtheria, rubella and many others.
Reaching herd immunity through vaccination sometimes has drawbacks, though. Protection from some vaccines wane over time, requiring revaccination. Sometimes people don't get all of the shots that they need to be completely protected from a disease.
In addition, some people may object to vaccines because of religious objections, fears about the possible risks or skepticism about the benefits. People who object to vaccines often live in the same neighborhoods or attend the same religious services or schools. If the proportion of vaccinated people in a community falls below the herd immunity threshold, exposure to a contagious disease could result in the disease quickly spreading. Measles has recently resurged in several parts of the world with relatively low vaccination rates, including the United States. Opposition to vaccines can pose a real challenge to herd immunity.
Herd immunity can also be reached when a sufficient number of people in the population have recovered from a disease and have developed antibodies against future infection. For example, those who survived the 1918 flu (influenza) pandemic were later immune to infection with the H1N1 flu, a subtype of influenza A. During the 2009-10 flu season, H1N1 caused the respiratory infection in humans that was commonly referred to as swine flu.
Infection (by vaccine or natural infection) with the COVID-19 virus creates immunity, a large number of people would have to become infected or vaccination 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.
Overwhelming the health care system
If many people become sick with COVID-19 at once, without any special protection for the older people and those who have chronic conditions, the health care system could quickly become overwhelmed. This amount of infection could also lead to a dramatic rize of number of death.
Having no choice
At this moment of writing, there is no vaccine available. When a working and effective vaccine can be available for the world population is unknown. It's very likely that such vaccine will be only available in the second half of 2021., but even that is not sure.
With other words, governments have three choices:
- Or they close down their economies and enforce lockdowns for the populations
- Or they don't close down the economies, protect the high-risk people and wait until natural immunization is applied, like in Sweden
- Or they fooling around with the Corona pandemic
Currently, only a few countries have a successful approach against the coronavirus. One of those countries is Sweden, which chose the natural way of getting immunization for its population and the results are excellent. In other countries they have a good approach against the virus with local shutdowns of the neighborhoods with high infection rate and intensive testing.
But most of the countries follow the advice of the WHO, which means that the so called "second wave" of coronavirus infections rages throughout the populations.
As a country, at this moment, when there is no vaccine available for a long time, there is no other option to have natural immunization.
The effects of enforced shutdowns of a nation
Enforced shutdowns of the nation means first of all the economy. Meaning that it cost tens of billions of dollars for the country, and worse, it means that the population is forced into poverty.
Some countries apply a second national lockdown. The effects of such second national lockdown is devastating for its population. Such countries select the choice between bad publicity and the actual destruction of their economy; the number of death by other reasons than the coronavirus is multiple times larger.
An enforced shutdown might bring the number of newly infected people down after some weeks, but there is no guarantee that when the shutdown ends, that the infections will be stopped. It's more likely the opposite.