Coronavirus: Is the Delta variant making it difficult for us to achieve COVID-19 herd immunity?

Although the number of coronavirus cases in the country have dropped down and people are going back to a state of normalcy, the emergence of new variants and the fear of a possible third wave has only left people restless and doubtful. "When will the pandemic end?" is the question that has started to irk so many, to which scientists and medical professionals are constantly looking for an answer.

The idea of herd immunity, which was so prevalent and seemed so achievable initially, is now becoming more and more impossible, due to many reasons, including the rise in the number of Delta variant cases.

Herd immunity occurs when a large population of people in a community gain enough immunity against the disease, making it difficult for the virus or the infection to spread. That said, when a sufficient proportion of a population gains immunity to a particular virus, the entire community is no longer susceptible to the disease. In respect to COVID-19, herd immunity can be achieved in two different ways i.e. through mass vaccination or by gaining natural immunity from an infection.

Read more: Coronavirus third wave: How to spot a Delta COVID infection (and ways to stay safe)

While a COVID vaccine can provide an individual with an artificial immunity against the SARs-COV-2 virus, a natural infection can also develop antibodies against the virus, making herd immunity a possible scenario.

When a large number of people contract the disease and recover from it, during the course of infection, they develop antibodies, preventing the possibility of a re-infection. Technically, COVID herd immunity can be reached when a large number of people contract the virus and recover from it. However, experts believe that immunity from natural infection may not be as efficient as COVID-19 vaccines.

In recent times, new emerging variants, especially the Delta variant, has become a source of major concern.

According to the Centre for Disease Control and Prevention, "The Delta variant is highly contagious, more than 2 times as contagious as previous variants." As per the health agency, there's also a few data that suggest, the Delta variant might cause more severe illness than previous variants in unvaccinated people.

That said, while Delta infections may provide natural immunity, due to its high transmissibility rate and the ability to evade vaccine-induced immunity, experts believe that reaching a COVID-19 herd immunity is almost impossible.

Read more: Explained: Why vaccinated people were at low risk during delta surge

At a time when herd immunity is the only way to end the pandemic, vaccination is of utmost importance. While COVID-19 is a highly infectious disease, the only way to tackle it is through mass vaccination.

However, of late, breakthrough infections have become increasingly prevalent and raised concerns in and around the world. Given that fully vaccinated individuals are also contracting the virus and developing mild to moderate symptoms, it only indicates that the virus is evolving and mutating, making it more resistant to vaccines.

Read more: Explainer: Why does the delta variant spread so fast?

Herd immunity can be achieved either through a natural infection or with the immunity acquired from COVID vaccines.

While experts believe that immunity for both vaccines and a natural infection are effective and strong, there is no telling for how long these immunity last. However, the existing studies and research suggest that immunity acquired from a natural infection wanes over time, which may add to our woes and hinder the route to reaching herd immunity.

Similarly, experts have suggested that vaccine-induced immunity may also diminish over time, especially when it comes to people with a compromised immunity. This has further lead to rising demands for booster vaccines.