Coronavirus: Immunity from infection vs immunity from vaccines, which lasts longer?

Immunity against coronavirus is a highly talked about concept right now. Even as authorities around the world are working to ramp up the pace of vaccination, it is also speculated that immunity achieved via a natural infection is much stronger, and negates the purpose of vaccination. A number of clinical studies to study the potency of natural antibodies are a testament to the same.

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Even so, with growing mutant variants, people across the world who haven't been vaccinated are getting reinfected with coronavirus, and even those who have been fully vaccinated, are contracting breakthrough infections.


ALSO READ: Do recovered patients only need a single vaccine dose?

So, while some level of immunity is essential to fight off future infections- what's more purposeful, antibodies from infection or antibodies from vaccines? Is one more effective than the other? We compare

The SARS-COV-2 virus infects the body and leads to possible inflammation and spreads to various parts of the body. Once the immune system recognizes the virus, it sends across defensive antibodies and WBCs to fight the infection. Once the infection is eliminated, the immune response in our bodies is triggered as a combination of mediated immunity and antibody production, which builds a level of lasting immunity. This is what happens when your body encounters other infectious strains of pathogens as well.

A vaccine contains fragments (inactive/weaker/ dead) of the virus strain or a form of spike proteins (such as the ones artificially made by mRNA vaccines) that mimic the behaviour of the infectious strain. Once the immune system recognizes the fragments or parts of the virus, it prompts necessary inflammatory reactions (otherwise known to be side-effects) and white blood cells into action and fights it away, remembering it well. With this process, antibodies are created. So, if and when the virus or pathogen is encountered in the future, the vaccine trains the immune system to recognize, fight and evade the virus without leading to a higher risk of infection.

While recovered COVID-19 survivors do have some level of natural immunity, they do require a COVID-19 vaccine at this moment. This is because while the levels of antibodies may offer some protection, a vaccine can go over and beyond natural protection and benefit them. It could also benefit those who are immunocompromised, or at a higher risk of reinfection.

However, in comparison to those who have zero history of infection, a recovered person may only require a single dose right now. While this is still being researched, medical experts believe that the prior infection quickly recognizes the vaccine's workings, mounting a stronger, quantitative antibody response (equal or more than 2 doses do). The presence of memory B cells also helps build lasting protection for a longer duration of time.

Right now, coronavirus immunity has been highly debated since scientists and experts yet do not completely know how effective, or lasting immunity against COVID-19 could be. While natural immunity is said to be at its peak for around 90 days post-infection, vaccines may offer a greater edge since they could be longer-lasting, and even upgraded in the future to offer strengthened odds of protection. Some vaccine models, such as mRNA vaccines (Pfizer and Moderna's) are said to be efficacious for longer timelines and grant more immunity.

As with a natural infection, clinical evaluations suggest that the immunity may stay at its highest levels for upto 90 days, and start to fall thereafter. Only in a few cases has it been seen to be lasting for longer durations, and may not be applicable for everybody.

As we have seen, variants of concern, such as the Delta and the Lambda variant are vast spreading and have severe features previously unseen before. The Delta variant is also currently one of the most dominant strains in the world and causing a spurt of infections in those who have been vaccinated, or the ones who have a previous infection history.

While both mediums do grant a certain level of antibody protection and immune defense, vaccine-generated immunity, at this moment, is stronger and offers greater odds of protection. There are multiple reasons for the same. For one, not only have the current vaccines clinically tested and found efficacious (even if lower) in respect to the current variants, they have also been proven to cut down on severity and mortality rates. Depending on the vaccine you do get, it could also work to greatly mitigate your risk of infection transmission as well.

In comparison to this, previously built immunity from infection (i.e., natural antibodies) might still offer protection, but we do not have enough data yet as to how well it reacts to specific variants. Natural immunity can also wane, or be less effective if a person has frail or compromised immunity.

Secondly, vaccines also offer an added advantage, since they can undergo timely upgrades and additions to make them more effective. Booster COVID shots are currently in works to mitigate the risk of infection against current severity-inducing variants, and any variants of concern that come up later.

Not only are vaccines known to create reactogenic side-effects, but vaccines also undergo many levels of testing (even if they are currently experimental).

The side-effects are generally what one can expect- even with an infection, but to a greater degree. As we are learning more about the infection, it is also becoming increasingly known that a fight with COVID-19 could lead to more severe, sometimes long-lasting consequences as well- some requiring hospitalization or increasing mortality risk.

Hence, not only are the side-effects, or symptoms caused by vaccines milder and temporary in nature, the risk of infection is much greater than battling smaller consequences with vaccines.