Within a few months, we were able to surpass 30 percent of the vaccinated population in Spain. This invites us to think about the form of immunity that we acquire. Is the natural immunity conferred from infection equivalent to that conferred by the COVID-19 vaccines? Can we measure this immunity with quick tests?
To get started, consider that Natural immunity after infection is conditioned by the different tactics with which the SARS-Cov-2 virus attempts to evade the immune system. In addition, the virus is able to mutate and generate variants that can also be more transmissible and virulent, which also affects the immunity it generates.
It should be noted that the two skills are different. The fact that the virus has reached a greater rate of transmission means that it can easily spread to a greater number of people, as is currently the case with delta variable, candidate to become the dominant alternative in a short time. However, a mutation that generates greater virulence would increase its severity even with a very small infection, something that thankfully has not happened so far with SARS-CoV-2.
How is immunity measured?
In principle, It can be assumed that natural immunity is broader Because it involves an immune response to a greater number of antigens than the immune response to a single antigen vaccine. This is the case with many current vaccines against COVID-19. Some use the complete protein S (AstraZeneca or Jannsen) as an antigen, and others only use the binding region of the virus entry receptor, called RBD (Pfizer or Moderna).
But a caveat must also be made here, because there is the potential to create vaccines against the inactivated virus, as they did with the SinoVac vaccine. In this case, it will be the immune response that they may provoke against all the proteins of the virus.
What seems indisputable is that it is not easy to measure the immune response. The antibody response, known as humoral immunity, is tested by rapid serological tests. In contrast, neither T-cell response nor cellular immunity can be assessed by any rapid test.
Finally, if we intend to compare the natural immunity conferred by vaccines, we must bear in mind that when vaccinated, we seek an immune response that neutralizes the virus and also provides us with long-term protection.
What does the data say?
Having said all this, the data we have so far indicates that Infected people generate an immune response to S protein that is much lower than the immune response caused by vaccines, both from RNA (Moderna and Pfizer) and adenovirus (AstraZeneca or Janssen).
On the other hand, it is true that the natural immunity of patients who have suffered from COVID-19 stimulates a large amount of antibodies that can last a lifetime. However, virus infections do not generate more neutralizing antibodies than RNA vaccines, for example. Rather, the opposite is true: Antibodies produced after immunization with RNA vaccines recognize the enemy better than those produced by natural infection.. The same is true for adenovirus vaccines.
The “equivalent” nuance when talking about antibodies is important, because it assesses the ability of these antibodies to block the virus. This job analysis provides more information about protection than serological tests, which only check the amount of antibodies against the virus.
Regarding the variable problem, the recombinant RNA, adenovirus and protein vaccines with the two-dose vaccination schedule produced sufficient neutralizing antibodies against the beta, alpha and gamma variants. Regarding the delta variant, there are no clinical studies yet.
Conclusion: vaccination is essential
In short, all studies show that vaccinated immunity provides greater protection than natural immunity. Vaccination is essential, even if we have already passed COVID-19.
Another indisputable conclusion is that many neutralizing antibody studies are worth doing with all available vaccines. On the other hand, comparing it with neutralizing antibodies of COVID-19 patients, whether they are asymptomatic, mild or severe. But also for conducting epidemiological studies that assess the importance of vaccines in a pandemic.
* You can read the original note by giving click
*to Carmen Alvarez Dominguez, Biochemist and Professor of Research in Health Processes at the International University of La Rioja
* The Conversation is an independent, non-profit source for news, analysis, and commentary from academic experts.