Since the pandemic began, many investigations have tried to determine the mode of spread of Covid-19 , the possibility of being infected a second time or the immunity generated by the body after passing the disease or after receiving the vaccine.
When there was still no approved vaccine against Covid-19, many people claimed that contagion was the best way to generate antibodies and become immunized against the virus. However, it is now known that even a person who has already passed the disease could be infected again , although it is a less likely case.
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This is where vaccines come into play, which are positioned as a way to reinforce that immunity, since “experts still do not know how long the protection that the body generates lasts after getting sick and recovering from Covid-19”, such and as explained from the Centers for Disease Control and Prevention (CDC, for its acronym in English).
Thus, studies have shown that vaccination provides a strong booster of protection even in people who have recovered from Covid-19. In fact, experts continue to investigate today how long vaccines provide protection and how long the protection provided by having been infected lasts.
How is immunity measured?
First of all, you have to know that vaccines use different types of antigen , such as AstraZeneca that uses the complete protein S or that of Pfizer that uses only the part that binds to the entry receptor of the virus, which is called RBD.
Furthermore, measuring the immunity that people possess is somewhat complicated, since antibodies can only be measured by rapid serological tests, but cellular immunity cannot, for example, be measured. Thus, it is the serological test that can detect the presence of antibodies against a virus and calculate the amount of antibodies produced after infection.
Are people with antibodies immune?
However, when asked whether a person with antibodies is immune to the virus, the World Health Organization responds that it is still being analyzed, although some studies already indicate that the majority of people infected with SARS-CoV-2 develop specific antibodies against this virus.
What is clear is that the levels of these antibodies can vary from one person to another , which makes it so difficult to give a single answer as to whether or not the person who has had the disease is immune to the virus.
On the one hand, those who contract the disease severely have high levels of antibodies, while people who contract mild or asymptomatic disease have low levels of antibodies. Thus, there are many studies that try to determine the levels of antibodies necessary to achieve protection and the duration of these antibodies, since it has been shown that over time the level of antibodies in a person who was infected decreases.
Are vaccines more effective in protecting?
Although there are still many studies that are being done on the efficacy of vaccines and their duration over time, the truth is that all approved vaccines have demonstrated their effectiveness in clinical trials, something that shows the decrease in cases of contagion.
In addition, some research indicates that the protection of vaccines is considerably superior compared to the immune response provided by vaccines. It is also necessary to note that a person who has had the disease will have antibodies, but these can decrease over time, so the vaccine represents an important reinforcement against the virus .
On the other hand, we must take into account another key point where vaccines are important: virus variants. Although the effectiveness of vaccines against the variants of the virus that are emerging is still being investigated, it does know that they continue to offer protection against severe forms of Covid-19 , as indicated by the Mayo Clinic .
Thus, taking into account all these differences between natural immunity and the immunity of vaccines, it is best to get vaccinated to get a greater boost against Covid-19 , even when the disease has passed, since it is not known which is the duration of natural immunity.