Immunological memory to SARS-CoV-2 assessed for greater than six months after infection
(16th November, Institute for Immunology CA, and University of California)
https://www.biorxiv.org/content/10.1101/2020.11.15.383323v1
Humans make:
SARS-CoV-2-specific antibodies
CD4+ T cells (helpers)
CD8+ T cells (killers)
Memory B cells
Neutralizing antibodies have generally not correlated with lessened COVID-19 disease severity
Passive prophylactic antibodies limits disease in animals
Less so after infection
Clinical hepatitis is prevented by vaccine-elicited immune memory even in the absence of circulating antibodies
Six months or more is usually required to ascertain the durability of immune memory
Cross-sectional study
N = 185
41 cases, more than 6 months
Recovered COVID-19 cases
43% male, 57% female
Mild, moderate, and severe COVID-19 cases
Multiple sites throughout the United States
92% of subjects were never hospitalized
7% of subjects were hospitalized
97% symptomatic
Results, B cells
Spike IgG was relatively stable over 6+ months
Spike-specific memory B cells were more abundant at 6 months than at 1 month…
detected in almost all COVID-19 cases
No apparent half-life at 5+ months post-infection
Smallpox vaccine, 60+ years
Influenza infection, 90 years
Results, T cells
SARS-CoV-2-specific CD4+ T cells and CD8+ T cells declined with a half-life of 3-5 months
Decay of circulating SARS-CoV-2- specific CD8+ T cell is consistent with what has been reported for another acute virus
Smallpox also uses CD4+ T cells, t1/2 of ~10 years
T cell memory might reach a more stable plateau, or slower decay phase, later than the first 6 months post-infection.
Each component of SARS-CoV-2 immune memory exhibited distinct kinetics
Immunity and reinfection
Memory B and T cell responses can take 3-5 days to successfully respond to an infection
SARS-CoV T cells 17 years after the initial infection
SARS-CoV, MERS-CoV, and SARS-CoV-2 are all betacoronaviruses
https://www.cell.com/immunity/pdf/S1074-7613(20)30312-5.pdf
SARS-CoV-2 is most similar to SARS-CoV-1
Followed by MERS-CoV (2012)
https://www.medrxiv.org/content/10.1101/2020.04.14.20065771v1.full.pdf
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It doesn’t matter that we were all doing social distancing, it doesn’t matter that I’m fit as a butcher’s dog, feel great – so many people do in my circumstances.
And actually it doesn’t matter that I’ve had the disease and I’m bursting with antibodies.
We’ve got to interrupt the spread of the disease…and one of the ways we can do that now is by self isolating for 14 days when contacted by Test and Trace.
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