June 15, 2021

Why Is Rapid Antibody Testing A ‘Game Changer’? Antibody vs Antigen Testing + Antibodies From Vaccines vs. Infection … What Is The Difference?

Right now when we are witnessing a sharp rise in the number of COVID-19 cases, more and more people seem to be interested in knowing about the antibodies produced in the body.

In recent times, with high recovery rates and signs of a certain slowdown, antibody tests are being talked about a lot. People who have recently recovered from the infection, or those who are now fully vaccinated are booking tests to determine how ‘protected’ they are. But, what exactly do COVID antibodies mean? And, is there a difference between the antibodies generated via vaccine and the ones gained through a natural infection? Confused with all the terminologies floating around?

Here is an explainer on the same…

What are antibodies and how do they protect us?
Antibodies are proteins produced by the immune system in response to previous infection or vaccination. They actually act as memory cells and help to fight the infection when exposed to the same virus in future. The number of antibodies present in the body is determined with the help of a blood test that is called an antibody test or serology test.

What is an antibody?
Antibodies are protective proteins produced by the immune system in response to the presence of a foreign substance. Whenever our body is exposed to any disease-causing foreign pathogens, our immune system produces defensive proteins to fight them, which are matched exactly to that organism. The antibodies recognise the invader with the help of proteins on its surface called antigens. These antigens either kill the foreign pathogens or lock them onto their antigens, which is later neutralised by other immune cells. The first antibody produced by our internal system after coming in contact with any diseases causing pathogens is called Immunoglobulin M (IgM) and the other one is called Immunoglobulin G (IgG). IgG antibodies are produced later by the immune system and play a role in creating memory cells that remain in the body to fight the virus in case of reinfection.

These antibodies are produced in our body in two cases- when exposed to the virus and after getting the vaccination. But the antibodies produced in both cases are different from each other.

Antibodies from infection
When you come in contact with the virus, your immune system has to go through the entire process of recognising the virus and then making antibodies for destroying it. The B cells present in the body make antibodies for different parts of the virus. Some of them turn out to be effective, while others not. This is how your body recovers and eliminates the virus. Your immune system recognises some antibodies that help to fight infection later. How long these memory cells can fight to prevent infection in the case of COVID-19 is hard to say as there are a lot of things about this virus that remains a mystery. However, studies carried out on other viruses in the past indicate that getting infected with any virus once declines your risk of a severe outcome in future.

Antibodies from vaccination
Vaccination is a way of building immunity against the virus without getting sick. Through the vaccine, the immune system is exposed to one or more proteins from the virus. This allows your immune system to make B cells that make specific antibodies that can neutralize that specific virus. The COVID shot helps in the formation of memory B cells, just like they do in natural infection. After getting the shot when you get exposed to the virus, these memory cells release antibodies that can target the virus. They eliminate the virus even before it can cause an infection in the body. In case of too much exposure to the virus, you may get sick, but the symptoms will be mild.

The difference in the antibodies produced from natural infection and vaccine
In both cases, the antibodies are produced similarly and have the same effect on the virus. However, there are some differences in the type of antibody and immune response you get from vaccination and natural infection.

In case of natural infection, the body first produces IgM type antibodies and then IgG. So your immune system does not provide immediate protection after getting exposed to the virus. Similarly, in case of vaccination, the body needs some time to produce the antibodies. It could take weeks to months to recognise the foreign cells.

When you are infected with the natural virus, your body produces different kinds of antibodies in response to it. Vaccination introduces only a part of the relevant virus, as a result, the immune system does not produce different kinds of antibodies as it would in case of a natural infection. This does not mean that the vaccination is less effective. Researchers carefully select the part of the virus that triggers an antibody response.

When it comes to what produces better antibodies, then the two situations cannot be compared. Natural infection and vaccination are two different things. Besides, not all vaccinations are made the same way and do not produce the same antibodies. It is still unclear which vaccine protects for a longer period. So, it is better to get the vaccination even after being infected with the virus to stay safe.