- Research suggests that people who have had COVID-19 and later receive the first dose of an mRNA vaccine develop exceptional immunity against a wide range of variants of the virus.
- These individuals could even have some protection against similar viruses that may jump from animals to humans to cause future pandemics.
- In people who have not had a natural SARS-CoV-2 infection, a third jab, or “booster,” may provide similarly broad protection.
Almost 2 years after COVID-19 emerged in Wuhan, China, a growing body of evidence suggests that the human immune system of some individuals has gained the upper hand against the virus, reports MedicalNewsToday.
The strong immunity against different variants of SARS-CoV-2
Several studies have found that people who recover from the infection and later receive the first dose of an mRNA vaccine develop strong immunity against a wide range of variants of SARS-CoV-2, the virus that causes COVID-19.
These individuals appear to have good protection against related coronaviruses that could cause future outbreaks.
Hybrid immunity
Scientists have used the term “hybrid” immunity to refer to the immune-strengthening effect of exposure to infection followed by vaccination. They have drawn this metaphor from genetics.
In people who have never had COVID-19, a booster shot of a COVID-19 vaccine may also provide hybrid immunity against variants of SARS-CoV-2 and related viruses.
Virologist Prof. Paul Bieniasz, says that several studies of hybrid immunity with his colleagues at Rockefeller University in New York.
He notes that hybrid immunity develops in people who had COVID-19 early in the pandemic and are then vaccinated 6–12 months later.
“While SARS-CoV-2 infection itself is thought to be quite short-lived, it is likely that some viral proteins and possibly even some infected cells persist, perhaps even for months,” he says.
He explains that this gives the immune system the chance to optimize and diversify its antibodies to recognize a wide range of variants. Vaccination then boosts the levels of these antibodies.
How effective are the antibodies?
In one of the most recent studies, scientists created a virus that contained 20 naturally occurring mutations of the spike protein of SARS-CoV-2, which is the protein that the virus uses to break into cells.
The spike proteins were resistant to antibodies belonging to unvaccinated people who had recovered from COVID-19 and to antibodies from people who had been vaccinated but never had COVID-19.
Antibodies from individuals who had recovered from COVID-19 and were subsequently vaccinated neutralized these spike proteins.
These antibodies were also highly effective against six SARS-CoV-2 variants of concern, including Delta and Beta. In addition, they neutralized several viruses in the same family of coronaviruses, known as sarbecoviruses, that usually infect bats and pangolins.
Antibodies from these individuals also neutralized SARS-CoV-1, which is the coronavirus that caused the SARS outbreak 20 years ago.
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Source: MedicalNewsToday
