The silent protector against Covid variants

Some 4.9 billion people or 63.9% of the world’s population have received at least one dose of the COVID-19 vaccine as of late February 2022. And more than 430 million cases of COVID-19 have been confirmed since the start of the pandemic.

Having experienced a previous COVID-19 infection or being vaccinated still left many people wondering how vulnerable they were to the virus.

Upon vaccination or infection with COVID-19, your body produces two types of protective immune responses. The first type involves B cells, which produce antibodies.

However, once a virus successfully enters the cells, antibodies are no longer effective. The virus begins replicating in the infected cells and spreading to other cells.

But by about six months after many people had been fully vaccinated, antibodies start declining. This is what led to the so-called “waning immunity” that researchers observed in the fall of 2021.

This raises the question: When do the different key players of the immune system emerge after infection, and how long do they last?

Throughout the COVID-19 pandemic, the public has widely and mistakenly believed that antibodies provide the bulk of protective immunity, while not recognizing the important role of killer T cells.

The killer T cells can recognize a virus-infected cell and immediately destroy the cell before the virus gets a chance to replicate. In this way, killer T cells can help prevent a virus from multiplying and spreading.

When antibodies fail, it is the killer T cells that are responsible for preventing the more severe outcomes of COVID-19, such as hospitalization and death.