It is often debated about which immunity is superior: whether natural or vaccine-induced artificial immunity. However, this question is misplaced: in fact, the immune response of our body is only one.
With immune response we mean that set of defense mechanisms put in place by our immune system in response to a pathogen. Our immune system does not distinguish whether the stimulus is real, as in the case of viral infection, or artificial, as in the case of vaccine administration. Either way, our body will develop an immune response, but are these responses comparable?
If one were to answer the question “is it better the immune response given by the vaccine or that of the natural infection?” the answer would be the vaccine for at least two reasons: the risk associated with vaccination is infinitely lower than that associated with natural infection and moreover the immune response generated by the vaccine is much more homogeneous than the disordered and often ineffective one of natural infection.
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The risk of infection
There is no need to remember the risks that characterize Sars-CoV2 infection: it ranges from a symptomatic illness similar to a bad flu to the most severe cases of bilateral pneumonia and death. We know that Sars-CoV2 virtually infects any organ in the body and the consequences can be very protracted as in the case of Long-covid. In addition to the classic symptoms of Covid19, purely respiratory, we also remember the presence of a whole series of cardiovascular symptoms, fortunately rarer.
In fact, it is estimated that the risk of developing myocarditis or pericarditis (inflammation of the heart and the membrane that covers it, respectively) following a Sars-CoV2 infection is about 1500 per million. In addition, there was also an increased risk of thrombosis, inflammation of blood vessels, arrhythmias and, finally, ischemias.
An extremely heterogeneous answer
In addition to the obvious risks associated with natural infection, we must consider the heterogeneity of the immune response in the population. In fact, if, on the one hand, the vaccine is a standardized and identical pharmaceutical product for the entire population, the virus is a living organism that has developed a whole series of mechanisms to evade, reduce and occasionally switch off the immune response.
In some people, Sars-CoV2 infection reduces the innate immune response. In fact, the virus has proteins that are able to reduce all those mechanisms put in place in the very first hours after infection: fever, inflammation, white blood cell recruitment, etc.
Numerous publications report cases of asymptomatic patients who did not develop neutralizing antibodies, thus suggesting a high predisposition to reinfection and risk of symptomatic disease.
Although there is no real positive correlation between the presence of symptoms and the production of antibodies, it is known that Sars-CoV2 infection does not evoke the same amount of antibodies in everyone. Furthermore, in some cases, Sars-CoV2 infection can generate dangerous autoantibodies that can contribute to organ damage or the onset of Long-covid.
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There is also data regarding Sars-Cov2’s ability to inhibit the formation of B lymphocytes and we know that these cells of the immune system are essential for the production of antibodies.
Sars-CoV2 is able to interfere with the development of germinal centers, a sort of “gymnasium” where B lymphocytes are trained to fight the virus.
Finally, there is evidence that Sars-CoV2 is able to turn off or anergize T lymphocytes, the snipers of the immune system responsible for eliminating cells infected by the virus.
The mechanisms reported represent only some of the strategies used by the virus to interfere with our immune response, pursuing its only goal which is to infect and replicate as much as possible.
Are the healed subjects protected?
On average, the healed subjects develop a good immune response and the protection conferred by recovery is comparable to that of a vaccine but, due to the countless mechanisms listed, it is recommended to be vaccinated after recovery.
The vaccine in fact guarantees excellent stimulation of the innate immune system thanks to the adjuvants, a sustained production of neutralizing antibodies and very high levels of B and T lymphocytes which are essential for immune memory and to combat severe disease.
Furthermore, the vaccine, although not without risks, presents risks that are infinitely less than natural infection.
Take Home Messages:
1) there is no natural or artificial immunity, only the way in which the immune response is evoked changes
2) The immunity evoked by the infection is extremely heterogeneous and often not sufficient to guarantee future protection
3) The vaccine ensures an excellent long-lasting immune response and is also recommended for healed subjects
REF:
https://www.nature.com/articles/s41591-022-01689-3
https://www.nature.com/articles/s41586-021-03631-y
https://www.sciencedirect.com/science/article/pii/S0092867420310679
https://wwwnc.cdc.gov/eid/article/27/9/21-1042_article
Aureliano Stingi, doctor in molecular biology works in the field of precision oncology. He collaborates with the World Health Organization in the battle against Covid-19-themed fake news
Twitter: @AurelianoStingi Instagram: Aureliano _Stingi