Coronavirus Vaccines and Immunity

Darshana Nadkarni Health Tech

By Darshana V. Nadkarni. Ph.D.
Twitter @DarshanaN

As coronavirus vaccines are starting to get rolled out, people have many questions. How soon a person receiving the vaccine may develop the immunity, how long the immunity will last, what if one does not take the second dose, can one still be a carrier without exhibiting symptoms and so on. Let us try to address some of those concerns. Additionally, please stay tuned to TiEcon blogs and sign up for the #TiEcon 2021 conference to occur May 6-8, 2021. Excellent lineup of speakers and panels are being planned in the health track.

Vaccines & Immunity

Vaccine, Chemist, Syringe, Ampoule, OutbreakCovid 19 Vaccines: Covid 19, a disease caused by the novel strain of coronavirus has defined the year 2020. As we stand on the verge of a brand new year, 2021 is likely to be defined by the vaccines to beat covid 19.

At no time in history, has there been such a rapid pace of innovation in developing vaccines to combat such a ferocious disease, as now. Currently, two vaccines authorized are Pfizer-BioNTech vaccine and Moderna’s vaccine. Just today news have come of J&J vaccine rolled out as well.  Additionally other vaccines in phase 3 clinical trials are developed by AstraZeneca, Janssen and Novavax. As far as I know, all of these are mRNA vaccines. mRNA stands for messenger ribonucleic acid and it can be described as messengers that carry instructions on how to make a protein. These messengers never enter the nucleus of the cell and therefore they can never alter or modify a person’s genetic makeup or DNA. These messengers only work with the body’s natural defenses to fortify them and help them develop immunity to the disease.

Any of these vaccines can cause some symptoms like fever, headache and so on.  Symptoms like fever and headache are signs that the body is building immunity. It is also likely that some of these symptoms may be worse after the second dose, rather than the first dose, so let the side effects not be a cause for concern as long as the symptoms are manageable. None of these vaccines will infect anyone with covid 19 and none of the vaccines can cause someone to test positive on Covid 19 tests. If a person develops immunity then it is possible that they may test positive on some antibody tests, but not on covid 19 diagnostic tests. If you got sick from covid 19, prior to taking the vaccine, very likely you may still benefit from getting the vaccine. So it is advisable for everyone to take the vaccine, including those who may have contracted the disease before.


There are different kinds of immunities and at this point, researchers don’t have all the answers. While it is hard to say exactly how long most people will be protected from the disease after receiving the vaccine, it may also vary from person to person. But here is some general info.

Sterilizing immunity: In this best case scenario of robust & durable immunity (like Measles), once a person develops immunity then the body is able to defend itself in all possible future infections. In coronavirus, this may be unlikely for most of us. However, some people with strong natural immunity may develop it.
Functional immunity: This is the type of immunity that is most likely in case of novel coronavirus. Here the person may contract the virus but the immune system will recognize & fight off the virus with very mild symptoms.
Waning immunity: In this case, a person infected or vaccinated would lose immunity over a period of time. This is likely in case of coronavirus and we may need to take booster doses. But even in this situation, most people will likely not be very sick as reinfections will be much less severe.
Lost immunity: In this case, a person would lose all immunity in some time & reinfection may be like first infection, carrying the same risk. Experts feel this is not very likely as most people will be able to generate some immune response and then develop some long term immunity.

Covid 19 is a serious disease. While many people only have a mild illness, others get severe illness and many are dying from it, all over the world. Covid 19 vaccines will help protect you by creating an antibody response, without having to experience serious sickness and without long term serious and detrimental effects on your body. Additionally, it may keep you from contracting severe form of the disease and passing it on to your loved ones.

There is some early indication the variants coming from South Africa, UK and Brazil, may be more contagious and deadly. It is possible one or two vaccines may be more effective on the mutations than the others.  But the bottom line is that all of the vaccines are tested and all of them are highly effective in preventing severe form of the disease.  Moreover, the speedier entire population gets vaccinated, the higher the chances that humanity can develop herd immunity.  And when more people develop immunity, the lesser the chance of people contracting the disease and spreading the virus and that also diminishes the chances of virus mutating. So it is in the best interest for all of us and the community at large, to quickly get vaccinated, regardless of which vaccine.

Another thing to remember is that ultimately, viral load, duration of exposure AND your immune system will determine your risk of infection and also the impact of the vaccines on you. Any of these factors can change the outcome for you. For instance, even if you are young and have great immunity, if you are exposed to heavy viral load (mostly from someone in close proximity) and if that occurs for a long time then your risk of infection increases. So please continue to take all precautions.

Register for #TiEcon 2021 at .  The 2021 conference will feature interesting health tracks and events and you will get an opportunity to listen to prominent medical professionals and scientists from across the world as they share their journeys towards incredible breakthroughs in fighting covid 19.