Scientists suggest COVID19 immunity obtained by infection and vaccination appears to be long-lived without the need for booster shots.

New research suggests that the immune system’s memory for most people who have recovered from Covid-19 or were vaccinated against it may continue to produce antibodies whenever they’re needed.

One study notes “that people who recover from mild COVID-19 have bone-marrow cells that can churn out antibodies for decades, although viral variants could dampen some of the protection they offer.”

The Research

According to its author, the study published in the journal Nature demonstrates that antibodies decline rapidly in patients who experienced mild infections in the first four months after infection and then more gradually over the following seven months, remaining detectable at least 11 months after the illness.

Antibodies, which are proteins that can recognize and help inactivate viral particles, are an essential part of the immune system’s defence.
Short-lived cells called plasmablasts are an early source of antibodies after a new infection.

Once a virus has cleared the body, these defensive cells recede and are superseded by longer-lasting antibodies named memory B cells. These B cells hide away in bones and patrol the blood for reinfection, producing antibodies for decades.

A second study posted online at the biology research site, BioRxiv, discovered that the memory cells continue to mature and strengthen at a minimum of 12 months after the initial infection.

Researchers evaluated a group of 63 COVID-19-convalescent individuals assessed at 1.3, 6.2 and 12 months after infection, 41% of whom also received mRNA vaccines.

The study also observed that in the absence of vaccination, the memory B cells remain relatively stable from 6 to 12 months. Still, that vaccination increases all components of the immunity response.

What does the latest research mean?

Both reports are consistent with the growing body of research that suggests immunity obtained by infection and vaccination for most people seems long-lived and will not need booster injections.

Vaccinated individuals who have never been infected, as well as a small percentage of people who have been infected but have not created a robust immune response, will almost certainly require booster shots.