24 July 2020 4224
Health Risk

About The Herd Immunity

During the COVID-19 pandemic, a term called 'herd immunity' has emerged, which is predicted to be the solution to this pandemic. Herd immunity is not a new term in the world of health. Herd immunity, aka community immunity, was first introduced to the world by two microbiologists named William Topley and Graham Selby Wilson in 1923. These two scientists illustrated herd immunity as the immunity a group has against a disease, which is mostly caused by people in that group have immunity to the disease. In other words, the immunity that some people have can help protect others who do not have immunity.

 

 

Image source: https://www.bjp-online.com/2018/12/portrait-of-humanity-the-guardians-david-levene-on-capturing-the-city/

 

Immunity itself can be achieved through two things. The first is using vaccination, in which the body will be injected with a small dose of virus or bacteria, which is the agent that causes infection, which has been weakened. It aims to "introduce" the virus or bacteria to the immune system, so that the immune system can prepare antibodies, aka "special soldiers" that can fight the virus or bacteria if one day the body is infected. Antibodies here are molecules that function to help the body fight infection and respond to foreign particles or antigens that enter the body. Well, vaccinations are in charge of inducing the immune system to produce these molecules.
 
How can vaccination create herd immunity?

For example, when someone gets the polio vaccine, their body will form specific immunity, aka antibodies against the poliovirus. Once upon a time, when a real poliovirus enters the person's body, the person's immune system is ready to fight the poliovirus, so this virus dies and does not cause polio disease. Even if the person is still infected with polio, the impact of polio they will suffer will be less severe than if the person does not receive the polio vaccine.
 
Imagine, if, at the same time, almost everyone in the same group as that person was vaccinated against polio and had immunity to the poliovirus. Of course, the chance for the poliovirus to spread and cause disease in this group is very small. Automatically, this condition can also protect people who have not or cannot get the polio vaccine in that group, such as newborns, pregnant women, the elderly, or people with weak immune systems, such as people with AIDS, sufferers of autoimmune diseases, and people who are undergoing chemotherapy.

Image source: https://nasional.kompas.com/read/2020/06/10/16391901/kelompok-rentan-perlu-mendapat-perlindungan-di-tengah-pandemi

 

The second way to gain immunity is through natural infections. Just like the vaccination process, when a virus or bacteria enters the infection process, our body will form antibodies against the virus or bacteria. After recovering from a disease, the body will "remember" the infection and the body will have antibodies to fight the virus or bacteria the next time they attack.
 
Until now, the vaccine to ward off SARS-CoV-2 infection is still in the development stage, and meanwhile, every day hundreds of thousands of people increase the number of confirmed cases and the lives who die due to this disease are still growing quite significantly. With the absence of a specific drug to treat COVID-19 and the formation of herd immunity through the vaccination process still unable to occur, an idea emerged to create herd immunity using the method of 'letting the infection'.

The problem is, the formation of herd immunity with the concept of 'letting go of infection' has a very big risk. To create herd immunity with this method, 60 - 80% of the people in an area must be infected. We take the example in Indonesia, yes. Currently, Indonesia has around 268 million inhabitants. If Indonesia wants the formation of herd immunity using the method of 'letting go of the infection', it means that 160 - 215 million people must be infected with COVID-19. With the case fatality rate (CFR) from COVID-19 in Indonesia which is around 5%, around 10 million people may become victims before herd immunity is achieved using this method. Therefore, the opinion of the World Health Organization (WHO) regarding the formation of herd immunity with the method of 'letting go of infection' is not a wise way to resolve the COVID-19 pandemic.

If we pay attention, herd Immunity here becomes like a double-edged knife that has two connotations. In a positive connotation, herd immunity will help protect individuals who do not have immunity to a disease, if there are enough individuals in the group who already have immunity to the disease. On the other hand, in a negative connotation, the process of herd immunity, especially with the method of ignoring the infection, will take a long time and of course will likely cause a large number of casualties

Sumber foto: https://www.trialsitenews.com/stanford-university-breakthrough-as-researchers-develop-antibody-test-for-covid-19/

 

Scientists at King's College London are currently studying the body's method of fighting SARS-CoV-2 by building up antibodies. As a result, the study revealed that people who have been infected and recovered from COVID-19 do have antibodies that are thought to make their bodies "immune" to future COVID-19 infections. But unfortunately, these antibody levels did not last long, even being informed that within three months the antibody levels had begun to decline.

Antibodies are like our memories, some things can be remembered well over a long time, and some things can only be remembered for a short period or can be forgotten very quickly. The length of time or not these antibodies last can depend on many things, including the agent causing the infection itself. For example, the antibodies created from the measles vaccination can last for such a long time that the measles vaccination can be given only once in a lifetime. On the other hand, the antibodies created from the influenza vaccination can only last 1 - 2 years, so, after that time, we are recommended to re-vaccinate to maintain existing immunity.
 
Also, there is a hypothesis which states that the severity of infection can determine the antibody level of the sufferer. A study in Wanzhou, China has researched a group of people who have tested positive for COVID-19. Some of them have symptoms and some of them have no symptoms. The results of the study revealed that within eight weeks, as many as 81% of asymptomatic people had experienced a significant reduction in antibody levels, while in the symptomatic group, only 62% of them had decreased antibody levels. If it's like this, then remember the Dragon Ball movie, huh. The heavier the injuries Son Goku and the Saiyans suffer, the stronger they'll become after they recover..hehehe.

 

Image source: https://www.hiclipart.com/free-transparent-background-png-clipart-zjulc

 

Considering that the immunity that exists after being infected with COVID-19 may not last long, it seems that the formation of herd immunity by letting the infection go is something that is less and less worth considering. Also, considering that the virus and its strains are still very likely to change and evolve, it seems that giving the COVID-19 vaccine also cannot be done with just one administration, but requires a booster in the future so that it can provide optimal protection for a long time. Therefore, let's pray together that an effective and safe vaccine for COVID-19 can be created immediately. Meanwhile, let us take care of each other and remind us to always adopt a clean and healthy lifestyle and always follow the existing health protocols.

 

 

 

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Author

dr. Laras Prabandini Sasongko, AAAIJ

Email: laras@indonesiare.co.id