VACCINE INDUCED Vs NATURAL IMMUNITY TO COVID-19
As we move closer to ending the pandemic, a critical question remains how long the people exposed to this deadly virus will keep on generating the neutralizing antibodies. In other words, it means how effective or lasting immunity one can develop after exposure to the virus. The answer to this is potentially complicated as every other day we are finding the new variants of concern evading our immunity and increasing the chances of new outbreaks. The remotest addition of delta and lambda variants are vast spreading, causing a spurt of infections and have severe features that were previously unseen before.
Immunity against Covid-19 develops either due to natural infection by the virus itself or by vaccine inoculation. While there has never been a pathogen where artificial immunity has outperformed natural immunity, corona virus seems to be unique in that respect. The immunity due to natural infection stays at highest levels for up to 90 days only and starts to decline thereafter. Only in few cases it has been seen to be lasting for longer durations and may not be applicable to everybody. The vaccine generated immunity, on the other hand at this moment, seems to be stronger and offers protection against many odds as well. It is not entirely clear why these differences in vaccine- and infection-elicited antibody responses exist. In both cases, antibodies are acquired from the immune system’s recognition and response to viral spike proteins. However, the vaccine presents the viral protein in slightly different conformations and it is possible that mRNA delivery may change the way antigens are presented to the immune system, leading to differences in the antibodies that get produced. Also, the natural infection only exposes the body to the virus in the respiratory tract while the vaccine is delivered to the muscle, which probably exposes the spike protein widely to immune system followed by a vigorous response.
While both mediums do grant a certain level of antibody protection and immune defence, the vaccine generated immunity is far more efficacious and long lasting. The vaccine induced immunity has an edge over natural infection as it benefits not only the healthy individuals but also enhances the immune response in those who are frail, immune compromised and/or at higher risk of infection. The vaccine induced immunity, in clinical scenario, has been proven to cut down on the severity and mortality rates as well as mitigate the risk of infection transmission. While recovered Covid-19 survivors do have some level of antibodies, a vaccine can go over and beyond natural protection and benefit them. It has been seen that even the first dose of vaccine inoculation mounts a stronger immune response in a recovered person and as the quantitative antibody response is stronger, whether a second dose is required or not in such subset of people remains debatable.
The timely upgrades and inclusions in vaccine manufacturing has helped in establishing the safer as well as potent versions. The current vaccine-elicited antibodies are more effective not only against the current strains but also against any variants of concern that may come up later because they target a broader range of places on the receptor binding domain than those elicited by natural infection. As vaccine induced immunity, at the moment, appears to be safer, longer lasting and efficacious, authorities around the world are trying to vaccinate the maximum number of individuals to provide immunity against the coronavirus disease. However, there are many anti-vaccine advocates who are discouraging people from getting vaccinated, arguing that immunity from infection is always stronger than vaccination. We need to understand here that vaccines are tested for their safety in ways that one could never do with a natural viral infection and also with infection, we don’t know how bad it is going to be. So by not getting vaccinated, we are just rolling the dice in favour of the deadly virus.
As humans are routinely infected and re-infected with other common corona viruses causing common cold, it is very much usual to catch cold from seasonal corona viruses year after year. However, unlike the situation for the common cold, as we have developed multiple Covid-19 vaccines the acquired immunity from vaccines will indeed produce long-lasting protection against SARS-CoV-2. The only favour we need to do is to roll our sleeves up for vaccine in maximum numbers rather than wait for natural immunity, bring down the transmission rate of infection, save lives of our nears and dears and ultimately reduce the likelihood of developing newer variants that might evade protection from the current vaccines.
Dr. Pawan Suri
Chief Cardiologist
SGL SuperSpeciality Hospital
Jalandhar, Punjab
Email: psuricardio@gmail.com
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