Since the outbreak of the pandemic it has been unclear whether or not exposure to COVID-19 results in our developing immunity, and if so, how long that immunity would last.
Two new studies are helping us to better understand how our immune systems adapt to this illness and what this means for vaccination.
Infection-induced immunity could last months or longer, according to research published in May.
Vaccination, on the other hand, may extend the lifespan of this immunity.
Another key finding from both of these studies is that many people who recover from COVID-19 and then receive an mRNA vaccine (such as the Moderna or Pfizer-BioNTech vaccine) may not require booster shots.
Is the vaccination immunity in individuals who have had Covid-19 different from those who have not ?
We found 2 separate studies for this question. Both studies included individuals who had been exposed to the coronavirus around a year before.
Immune cells in our bone marrow preserve a “memory” of the coronavirus, according to one study published in Nature, and are able to generate protective antibodies to avoid reinfection.
The findings show that convalescent immunity will be highly long-lasting, and that convalescents who receive accessible mRNA vaccines will develop antibodies and memory B cells that should protect them from circulating SARS-CoV-2 variations, according to the study authors.
The other study, which has not yet been peer-reviewed, discovered that these immune cells can mature and strengthen for up to a year following infection.
How the immune response works
Our immune systems include B cells, which are a type of white blood cell (WBC) responsible for humoral immunity, according to Dr. Miriam Smith, chief of infectious disease at Long Island Jewish Forest Hills, Northwell Health in New York.
They begin and mature in the bone marrow, then travel to the spleen and lymph nodes.” “In reaction to an antigen, a virus, or a bacterium, B cells become activated.” says Smith .
She claims that the “memory” B cells remain after infection, allowing the immune system to “remember” and reawaken to fight the same virus or bacteria if it invades again.
More booster shots in the future?
These new trials also suggest that most people who recovered from COVID-19 and were later inoculated with one of the mRNA vaccines will not require booster doses to remain virus-free.
Vaccinated people who haven’t had a previous infection, as well as the limited percentage of people who have had the disease but didn’t have a strong enough immune response, will almost certainly need booster shots.
In fact, an article in The New York Times this week studied the immune response of people who have had COVID and are vaccinated, and they had an incredible immune response — much greater than someone who previously hadn’t encountered the virus in any form.
So, if someone has had COVID-19 and is inoculated, they will never need a booster,” he explained. It appears that they have stronger immunity than someone who has been vaccinated (and has never had a previous infection).
The bottom line
People who recover from COVID-19 generate antibodies that can persist up to a year, according to two recent studies.
Reinfection, while rare, can occur, according to experts, and getting vaccinated with one of the mRNA vaccines (such as Pfizer-Moderna) BioNTech can dramatically enhance immunity.
Experts also believe that because mRNA vaccines produce such a strong immune response in this group, persons who have had COVID-19 may not need booster shots to maintain protection.
Experts warn, however, that patients who receive the vaccination but have not had COVID -19 before will almost certainly require booster shots.