Coronavirus: Here's why you can get COVID-19 again

Most people who catch COVID-19 are said to develop a certain amount of immunity that keeps them safe from a possible reinfection, at least for about 3 months to 5 years, reveals an October 2021 study. Another study suggested that immunity from a previous infection could last for as long as 8 months. However, these studies were conducted prior to the emergence and prevalence of COVID's Omicron variant, which was first detected in South Africa in November last year.

As compared to previous variants, experts believe Omicron is more capable of reinfecting people who have had COVID in the past. A study conducted by the Imperial College London's COVID-19 response team found that the risk of reinfection with Omicron is 5.4 times higher than with Delta. So those who were previously infected with the Delta could be 5 times more likely to be infected with the Omicron.

In light of such findings, it is important to understand the reason behind why people catch COVID twice or repeatedly. Let us find out!

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One of the reasons why a person becomes prone to a reinfection is the emergence of new mutating virus strains also known as variants.

As is known viruses are programmed to mutate. Variants occur because of the changes or the mutations in the virus' genetic material, which either make them more infectious, transmissible, severe or able enough to dodge vaccine-induced immunity.

Given that the structural and spike protein of the virus change over time, the body's antibodies from the previous exposure fails to identify the infectious agent, making a person more at risk of reinfection. And the increased transmissibility only makes it worse, giving way to more mutations, leading to many other variants and subvariants, so is the case currently.

Although the cases in certain parts of the world are plummeting, we are somehow surrounded by new strains of the SARs-CoV-2 virus.

Apart from the BA.2 'Stealth' Omicron that is a sublineage of the highly contagious Omicron, there are many recombinant strains currently in circulation, namely XF, XD and XE, which could be 10 times more contagious than BA.2, says the World Health Organization (WHO).

Once you get infected with COVID-19, your body builds a strong immune response, remembers the virus particles and builds antibodies against it. This enables your immune system to fight possible future infections. However, experts believe when your body does not come in contact with the virus for a long time, the memory of the viral particles may fade and the production of antibodies may slow down, which is why your body's immunity may wane over time, leading to possible reinfections.

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Getting yourself vaccinated is currently the best way to keep yourself protected for the SARs-CoV-2 illness. If you're someone who has had coronavirus in the past and is fully vaccinated, then you're mostly likely to have developed double protection against the virus.

However, given the emergence of new COVID-19 variants, not only have breakthrough infections become more prevalent in the past, but there has been a rising number of reinfections. From the mutations in the virus genes that give it the ability to dodge vaccine-induced immunity, to diminishing vaccine effectiveness in the long run, experts believe getting re-infected could be a possibility.

That said, booster shots have become the way ahead and are currently being administered in several countries, including India. It helps re-expose the body's immune system to the immunizing antigen, the memory of which may have waned after the previous vaccine doses.

Although there is no definite data to tell how soon you can catch COVID-19 again, the Centers for Disease Control and Prevention (CDC) says, “the latest data suggests that retesting someone in the 3 months (30-90 days) following initial infection is not necessary unless that person is exhibiting the symptoms of COVID-19 and the symptoms cannot be associated with another illness.”

As per experts, people who have had COVID in the past can expect to experience a milder or a less severe re-infection. It is believed that re-infected individuals are likely to have some pre-existing immunity from their primary infection, which just like vaccines, reduces severity. In addition, vaccinations may provide a double layer of protection against COVID severity, especially in those who catch COVID twice.

As COVID restrictions ease in most parts of the world, it is important that you take responsibility for your actions.

If you develop symptoms that resemble COVID-19, make sure you self-isolate until your symptoms improve. To be sure, you can resort to coronavirus testing, but until you receive your reports, stay isolated, wear a mask and follow proper hand hygiene.