The Journal of Clinical Medicine published one of the most comprehensive natural immunity studies from Covid-19 ever. The authors of the research analyzed every aspect of natural immunity, therefore its duration after Covid-19 and post-vaccination; the various types of immunity; the likelihood of reinfection and its clinical manifestations in recovered patients, also comparing vaccinated and unvaccinated; the efficacy of natural and vaccine-induced immunity against the Omicron variant; finally, the incidence of adverse effects after vaccination in healed subjects compared to subjects naïve (who have had no previous therapeutic exposure to a specific drug) to COVID-19.
To make it happen they have been analyzed 246 scientific articles related to the COVID-19 literature, published from April 2020 to July 2022. The one used by the researchers is a very consolidated methodology at a scientific level. This is the review of fictional literature, a search method through which scholars search for a series of scientific articles on the various databases and what is relevant – regardless of the conclusions it reports – is inserted into the research, which ends with a critical discussion of what emerged. The researchers’ study was then sent by Journal of Clinical Medicine to three reviewers, two of them they did not suggest any changes, while one asked to specify some parts better but without any substantial modification to the methods and contents already existing. It should be emphasized that, for reasons of transparency, the review process can be consulted on the article.
The goal of the researchers was to clarify, by evaluating the highest number of studies possible, on the efficacy and on the differences concerning natural immunity, induced and hybrid immunity (vaccinated subjects affected by COVID-19) and to highlight the development and consequent efficacy of these types of immunity within the general population, for resolve the numerous uncertainties surrounding the subject.
The study, published on October 25, 2022, found that the vast majority of individuals, once cured of COVID-19, develops natural immunity effective over time and providing protection both against reinfection (even in the case of variants) and against serious diseases. It has also been shown to be vaccine-induced immunity decay faster than the natural one and that in general, the severity of the symptoms of reinfection is significantly less than with primary infectionwith a lower degree of hospital admissions (0.06%) and extremely low mortality.
In an interview with L’Indipendente, the doctor Sara Diani – first signer of the study -, underlined how “Among the recovered, the risk of developing adverse effects following vaccination is 50% more compared to unhealed individuals. Consequently, in the face of what emerged, the relationship should be re-evaluated risk-benefit of this drug on people and also the relationship benefits-costs that our country would support in case of unnecessary inoculations. In a historical moment like the one we are experiencing in an economic crisis, therefore, using doses for those who do not need it would be a waste of money as well as being a risk for individuals who have already recovered ».
Natural and vaccine immunity compared
The analysis of the literature carried out by the researchers concerning natural immunity (post-COVID-19), highlighted a series of results that indicate good immunological protection in the vast majority of individuals. Protective antibodies and immunological memory cells have been found in many studies with follow-up from 12 to 18 months after healing, and their presence has been demonstrated even more prolonged with the lengthening of observation times. Notably, a Swedish research with a follow-up after natural infection of up to 20 months showed a 95% protection rate from infection and 87% from hospitalization, in those who have not added vaccinations.
Vaccine-induced immunity, on the other hand, has been shown to decay faster natural immunity (post-COVID-19). This type of protection is very good after the first 14 days, however it tends to decline rapidly over the following months, almost disappearing about five months after the second dose. Overall, SARS-CoV-2 infection appears to have provided greater protection compared to that offered by the single-dose or double / triple vaccine.
Also, due to the immune response following COVID-19 infection, further administration of vaccine doses, especially from the second onwards, does not lead to a significant improvement in immunity. Indeed, due to repeated vaccinations there is the possibility that a series of pathological mechanisms may occur related to dysimmunity.
With respect to hybrid immunity, a lower level of evidence is available for the literature on the efficacy of the latter, since the results of the studies are sometimes contradictory. “Further investigation is therefore needed, considering that post-vaccine local and systemic adverse events are 40% and 60% higher, respectively, in exposed subjects with a previous history of SARS-CoV-2 infection.” the researchers say.
The authors, in the conclusion of the study, commented on the results obtained as follows: “The vaccination of healed individuals should be re-evaluated, since they seem to show a more effective and lasting natural immunity than that induced by the vaccine, as is already known for other diseases. infectious. Although, most likely, the definition of the individual’s immunological profile towards SARS_CoV-2 would help to personalize a better preventive / therapeutic decision-making process, always in combination with the clinical picture and anamnestic background. “
Therefore, truths that have been denied or ignored until now continue to emerge. After Pfizer’s admissions regarding untested vaccines blocking transmission and the truths about early therapies, those regarding natural immunity and adverse effects are also starting to emerge.[di Iris Paganessi]