How long does immunity from COVID-19 last?

Some curious facts everyone wants to know about Coronavirus.

Coronavirus is entirely a new virus. Only the people who have already been exposed to Coronavirus have some immunity. Understanding the virus behavior, mode of action, spread, and control is the most challenging task. Scientists worldwide are working hard to develop a successful vaccine that will minimize the death toll because of COVID-19. Although researchers are working on multiple aspects, from learning and managing the virus, there is still much more to know about immunity, especially after corona infection. And the first question that makes everyone curious is how long this naturally build immunity lasts.

The body’s immune system is a built-in defense mechanism that scans and destroys harmful invaders, usually in two ways:

1. Innate immune response:
Its first response of our body- an instant and speedy action. The immune system recognizes the foreign agent and plays around it. This immune response comprises physical filters, chemicals-released in the bloodstream, and immune cells- an army that zaps the infectious microbes.
However, this system works at a very base level for a brief interval. It just identifies the general threats but does not mainly kill the Coronavirus to 100% accuracy. It will not learn, and it will not grant us immunity against the Coronavirus in the long term.

2. Adaptive immune response:
If the virus crosses the innate immune response boundary, adaptive immune response activates, which is more target-specific and effective. Adaptive immunity includes white blood cells-specific to produce antibodies. Antibodies are protective proteins produced in response to the foreign substance, called an antigen. Antibodies latch onto antigens to remove them from our bodies. Adaptive immunity also uses immunological memory to learn about the threats our body faced in the past and uses the immune response, quickly fixing the virus.

The memory of the immune system is like us-it distinctly remembers certain diseases, but it sometimes forgets.

Whether or not adaptive immunity is helpful, the answer is solely based on various factors, such as the person’s health, genetic makeup, age, and gender. For instance, some old age people do not develop complete immunity against infections as compared to youngsters. Likewise, people with pre-existing health issues will not be benefited sufficiently from this immunity, mainly if their pre-existing disease affects the immune system.

However, if the adaptive immune response is sufficiently strong, the infection will leave a lasting memory that will provide defense in the future. One research showed that antibodies in survivors of COVID-19 remained for six months after recovery. It means that after six months, survivors of COVID-19 are likely to be reinfected.

A vaccine is a preparation of weakened microbes of a disease that activates adaptive immunity. The vaccine helps our body in developing long-term immunity against infections, which can last for even decades. It achieves this by provoking the body to produce a long-lived B cell and T cell memory.

Usually, the immunity team takes time to respond to the invader microbe that makes us sick. The virus utilizes this time efficiently, keeps replicating and infecting as many tissues as possible. The vaccine is designed to help our body build up this natural immunity before that specific virus infects, hence serves as a time saver. Successful vaccinations produce sterilizing immunity, a form of immunity that completely blocks recurrent infections.

If the recently created COVID-19 vaccine causes sterilizing immunity, then the pandemic immediately ends and restore day-to-day life.

Perhaps.

The scientists are still figuring out the “cross-reactivity” among different types of flu viruses.

Laboratory experiments have shown that the T cells of certain people who suffered from SARS or common cold coronaviruses may even fight the novel Coronavirus.

How much protection it provides is unclear yet.

The positive antibody test means your body contains antibodies, witnessing that you have been exposed in the past.

But are you immune to Coronavirus's reinfection is a subject of debate, and the researchers are eager to address it. In certain illnesses, antibodies' existence means that you are immune or shielded from a respective disease. Your body has learned to recognize the virus and has produced enough antibodies for future defy.

For certain viruses, such as measles, immunity is life longing, but it’s not valid for all. Sometimes, immunity fades with time. Researchers hope that having some coronavirus antibodies can protect you from a more severe attack of COVID-19.

We need more research to understand the association between antibodies and COVID reinfection.

It matters a lot!

Knowing immunity will reduce the lockdown if it is clear who is not at risk of catching and spreading the virus.

If the currently designed vaccine does not provide long-term immunity, then we need time to re-invent the vaccine. Alternatively, we change the duration of vaccine intake; either we receive it like the flu shot-once a lifetime or once per annum.

Furthermore, there are still some big questions we need to answer yet.

A Bio-scientist and content creator by profession and passion. I love to connect science, technology, and the arts.