Antibodies against COVID-19 vary with vaccination vs natural infection

August 27, 2021
Antibodies against COVID-19 vary with vaccination vs natural infection

New research conducted at Rockefeller’s Laboratory of Molecular Immunology in New York suggests a natural infection may induce maturation of antibodies with broader activity than that conferred by an [mRNA] vaccination. While vaccination produces greater amounts of circulating antibodies than natural infection, the overall antibody response, or memory B cells, birthed from a natural infection are more potent and adapt at eliminating viral variants of pathogens.

In addition, memory B cells produced by vaccination peak and fade within only a few months; those produced by a natural infection evolve over time to protect against severe disease for decades.

Related: Fast-forming, improved antibodies offers long-lasting protection against COVID-19

As to why the antibodies or memory B cells produced by natural infection might be expected to outperform those produced by vaccines, the researchers hypothesise that the immune system may respond differently to viruses that enter through the respiratory tract than those that are injected. It is also possible that the virus persists in the naturally infected for weeks, giving the body more time to mount a robust response. The vaccine, on the other hand, is flushed out of the body mere days after triggering the desired immune response.

In this research, Rockefeller’s Professor Michel C. Nussenzweig and colleagues resolved to tease out any differences in memory B cell evolution by comparing blood samples from convalescent COVID-19 patients to those from mRNA-vaccinated individuals – the latter had never suffered natural infection.

The memory B cells of patients who were vaccinated evolved rapidly to produce increasingly potent memory antibodies. But after two months, progress stalled. The memory B cells were present in large numbers and expressed potent antibodies, but were not getting any stronger. Although some of these antibodies could neutralise the deadly delta and other variants of the coronavirus, there was no overall improvement in breadth of function.

With convalescent patients, on the other hand, memory B cells continued to evolve and improve up to one year after infection. More potent and more broadly neutralising memory antibodies were coming out with every memory B cell update.

Nussenzweig said that memory B cells can be expected to undergo limited volleys of evolution in response to vaccines, a finding that may have significant implications for the design and rollout of booster shots. A booster for the currently available mRNA vaccine(s) would be expected to engage memory cells to produce circulating antibodies that are strongly protective against the original virus and somewhat less so against the variants.

“When to administer the booster depends on the object of boosting: If the goal is to prevent infection, then boosting will need to be done after 6 to 18 months depending on the immune status of the individual. If the goal is to prevent serious disease, boosting may not be necessary for years.”

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