Vaccines against covid could give “superhuman immunity”, stronger than if the disease is passed
The researchers Dennis Burton and Eric Topol have published in ‘Nature’ a correspondence in which they address the perspectives of the immunity of vaccines, comparing the available data on covid vaccines with those on vaccines against other diseases.
They are optimistic that vaccines against the current pandemic are in the group of “superhuman”
Can the vaccine generate an immunity superior to that generated by the infection itself? Could the artificial immunity (the one generated by the vaccine) be better than the natural one (the one generated by the disease)? Not only can it, but it must. But it does not always happen that way.
Throughout history, there have been vaccines that have generated stronger immunity than natural ones, and others that have not. What will happen to the ones being developed for SARS-CoV-2?
This is what the American cardiologist, geneticist and researcher Eric Topol has asked himself. In a correspondence that has just been published in Nature, Topol analyzes different types of immunity of different vaccines and is optimistic with which they will offer the vaccines against this new coronavirus, or some of them, at least. They could become what he calls “superhuman vaccines”, in which “the immune response they generate is greater than that generated by natural infection.” Among them are, for example, the tetanus or human papilloma vaccine.
In general, natural immunity is superior to that generated by the vaccine. “If asked, many scientists will subscribe to this claim: natural infection provides better immunity than vaccination. There are many pathogens for which natural infection induces stronger immune responses and a longer lasting immunity than vaccination ”, he explains in his study. And he gives an example of this: the measles vaccine. “It may not offer complete protection for life, but it has been shown to be good enough to keep the disease under control when administered massively.”
In the tetanus vaccine, the opposite occurs. It would be an example of those “superhuman vaccines” that Topol talks about. He explains that the infection “produces the toxin in a very powerful way but in small amounts, enough to cause serious illness but not to generate a strong immune response of antibodies.” Instead, the vaccine “generates enough antibodies to provide protection against the toxin for a decade or more. Therefore, vaccination is recommended even for those who have been infected and have shown symptoms.”
But if we talk about viruses, “the example par excellence of immunity superior to that induced by infection is the HPV vaccine,” says the human papillomavirus vaccine. Strains that cause genital cancer “induce a low antibody response that takes a long time to develop (one study speaks of more than 8 months). In contrast, two or three intramuscular injections of one of the HPV vaccines induce potent neutralizing antibody responses ”.
Knowing which category the SARS-CoV-2 vaccines belong to is not easy yet. “The answer to this question will only be known as more data is collected from the ongoing studies on vaccines and natural infections,” warns Topol. But he assures that what we know so far about the most advanced vaccines is “encouraging.” Pfizer and Moderna speak of a reduction in infections of around 95%, and both generate neutralizing antibodies.
Although there are also other less encouraging data. The levels of these antibodies are “highly variable” from one person to another, and even in some cases, “they may not provide immunity”, warns the researcher.
“There are isolated reports of reinfection with SARS-CoV-2 associated with an insufficient initial antibody response, although data on its importance are not yet clear.” Faced with these doubts about natural immunity, “several vaccines are expected to induce important cellular immune responses,” says Topol.
It recognizes that there is an important factor, both in natural immunity and in that generated by the vaccine, that we still do not know: how long does this immunity last? Some studies have seen the antibodies last for several months, but others have seen them decline rapidly. And the researcher warns: “It is likely that the durability of antibody responses is” modifiable “if a correct choice of vaccine is made.”
For all this, the researchers send an optimistic message. “Overall, we are optimistic, given the number of platforms they are investigating and the enormous efforts underway. A vaccine (or vaccines) against COVID-19 that offers an immune response and protection superior to that achieved through natural infection is an achievable goal ”, concludes Topol.