What Happens To Immunity Levels After COVID-19 Infection?

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Australian scientists have described the evolution of immunity levels up to four months after COVID-19 infection, and have found that while antibody levels drop dramatically within the first month or two, the decline then slows substantially.

The findings suggest that protective COVID-19 vaccines should ideally elicit stronger antibody responses than natural infection.

The research team, which includes Dr. Jennifer Juno of the University of Melbourne, principal investigator at the Peter Doherty Institute for Infection and Immunity (Doherty Institute), has been investigating how the immune system, in particular B cells and T, responds to COVID- 19 protein spikes.

The spike protein allows SARS-CoV-2 to adhere to and enter human cells and is crucial in inducing neutralizing antibodies to protect against reinfection.

B cells are responsible for producing the antibodies that recognize SARS-CoV-2, while T cells play an important role in supporting the development of the B cell response.

Dr. Juno said that one of his surprising observations was that during the four months they were tracking patients, the number of B cells that recognize the spike protein actually increased in almost all of them, regardless of the severity of their disease. .

“This is interesting because our work and other recent studies suggest that these B cells continue to accumulate and potentially evolve over time. That should be useful for protection in case of another exposure in the sense that those ‘memory’ cells should be able to be activated again, “said Dr. Juno.

“While we don’t yet know how much antibody you really need to protect yourself, either through a vaccine or through natural infections, recent results from phase 3 vaccine trials should soon allow us to understand how long natural immunity should last.

“Furthermore, what remains to be understood is whether these changes in B-cell memory can help the immune system to recognize and protect itself against the new SARS-CoV-2 variants that are currently emerging.”

Dr Juno said that recent data on the major vaccines shows that they are eliciting at least twice the levels of antibodies than natural infection, which is very encouraging.

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More information:
Adam K. Wheatley et al. Evolution of immune responses to SARS-CoV-2 in mild-moderate COVID-19, Communications from nature (2021). DOI: 10.1038 / s41467-021-21444-5

Provided by the Doherty Institute for Infection and Immunity

Citation: What Happens to Immunity Levels After COVID-19 Infection? (2021, February 22) retrieved on February 23, 2021 from https://medicalxpress.com/news/2021-02-immunity-covid-infection.html

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