Herd Immunity for COVID-19 – Risks in Society

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Neucrad Health May 18, 2020

When the novel coronavirus started to impact various regions across the globe, different countries tried unique approaches to manage the pandemic. One such idea was to implement herd immunity amongst the population. In this approach, a majority of the inhabitants of a country develop an antibody against a virus either through infection or through vaccination. However, inching towards herd immunity also has its share of woes. Healthcare facilities may get strained beyond its capacity while reaching out to infected patients. It may impair the complete healthcare system of a country. Let us have a look at the meaning and significance of herd immunity concerning SARS-CoV-2 virus.

What is herd immunity?

Herd immunity or community immunity is a condition when a high percentage of a country’s population becomes immune to a specific disease. Boris Johnson, the prime minister of the United Kingdom, also talked about this idea while dealing with the COVID-19 pandemic. Based on the infectious nature of a virus, a region requires 70 to 90 per cent of its population to develop antibodies for the successful application of herd immunity. In this way, even the people who do not have antibodies in their system would become protected against a pathogen as the immune people surrounding them act as a buffer. If local infection occurs in a specific group of the population, it will not give rise to an epidemic or a pandemic.

How has herd immunity worked in other diseases?

Human beings have been able to eradicate many infectious diseases by developing herd immunity. In the early times, mumps, measles, chickenpox, tuberculosis, and polio were rampant in society. Every year thousands of victims lost their lives after developing these ailments. However, with the discovery of vaccines, nowadays, there are fewer outbreaks of these vaccine-preventable diseases. Moreover, these outbreaks do not scale-up to epidemic or pandemic as a large group of the population remain immune to them through the development of antibodies. They act as a buffer, and the outbreaks remain limited to a locality. Usually, children and those individuals who have skipped vaccination fall prey to these infections.

Why is it dangerous to go forward with herd immunity in COVID-19 pandemic?

It will be complete stupidity if any country opts for herd immunity in case of COVID-19 pandemic. First of all, the SARS-CoV-2 virus is highly infectious with a high transmission rate (RO; R-nought or r-zero). Studies reveal that the RO of SARS-CoV-2 virus can go to as high as 3.6 to 4.0. It indicates that a single infected person can transmit the virus to four healthy individuals. In this way, a large number of population will get infected with this deadly virus within a short span of time. Healthcare facilities will not be able to accommodate them and provide adequate care. As a consequence, a large number of people will lose their lives.

Moreover, the mortality rate of the SARS-CoV-2 virus is around 3.4 per cent (according to the World Health Organisation conference, on March 3rd). It is much higher than the seasonal flu (mortality rate of 0.1 per cent) and swine flu (mortality rate of 0.2 per cent). Additionally, the SARS-CoV-2 virus is frequently mutating, so the antibodies developed due to infection may not last for the entire life. So, in this scenario, the government cannot take the risk of unleashing the virus across society. They are enforcing lockdowns and social distancing measures to arrest the transmission of the virus.

What should we do in the current situation?

In the present circumstances, we should go on practising social distancing and limit outdoor activities as far as possible. Schools should conduct online classes, and employees should resort to working from home. Hopefully, within a year, vaccines will be available, and treatments of COVID-19 infection will become more effective. Till then, we should refrain from physical contacts with outsiders and use face-covers whenever we venture out of the house.

Reference:

1.     Herd immunity and herd effect: new insights and definitions.

2.     Vaccine herd effect

3.     Understanding Herd Immunity.

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