Our systematic #review of #SARSCoV2 antibody-mediated #immunity is out as a pre-print. #covid19. Short thread on the main questions and findings from the literature on endemic coronaviruses, MERS, and SARS medrxiv.org/content/10.110… 1/8
Antibody kinetics after infection: time to detection is similar for SARS and SARS-CoV-2 (11-12 days), and longer for MERS (16 days). IgG wanes over time but has been detected up to three years following infection. Key gap: studies of asymptomatic/mild infections 2/8
Antibody responses and severity: antibody kinetics varied among illnesses of different severity with longer duration of detectable antibody associated with more severe symptoms. Key gap: will mild cases of SARS-CoV-2 have detectable serum responses? 3/8
Correlates of protection: human challenge studies show that some levels of serum IgG, IgA, neut, mucosal IgA protective against infection and disease. However, challenge studies show re-infection with same strain possible in 1 year. Key gap: lack of evidence for SARS and MERS 4/8
Cross-reactivity: within Alpha- and Beta-CoVs but minimal between groups. SARS and MERS elicit antibody responses to endemic CoVs, but not vice versa. This is good news for assay development. Key gap: no evidence on cross-protection 5/8
Immunopathogenesis: many proposed mechanisms for how immune reaction to infection can cause damage. Key gap: no strong causal evidence yet for antibody-dependent enhancement (ADE). However, vaccines and therapeutics have to address this risk 6/8
Population seroprevalence: serosurveys for endemic CoVs show that most people get infected with multiple strains in childhood but adults still get CoV infections – evidence that lifelong, complete immunity not acquired. Key gap: immunity to SARS-CoV-2 may be different 7/8
Conclusions: many of questions still unanswered for #SARSCoV2, but big implications for testing and deployment of therapeutics, vaccines, and non-pharmaceutical interventions. Other CoVs represent our “best guess” at immune responses to SARS-CoV-2 8/8
