RESUMO
Variants of SARS-CoV-2 may evade natural and vaccine induced immunity and monoclonal antibody immunotherapeutics. There is an urgent need to know how well antibodies, induced by healthy and Clinically Extremely Vulnerable (CEV) patients, will bind and thus help reduce transmission and severity of infection from variants of concern (VOC). This study determines the cross-reactive binding of serum antibodies obtained prior to and 28 days after a third vaccination in three cohorts; a health care worker cohort who received three doses of Pfizer-BioNtech (PPP), a cohort of CEV patients received two doses of the AstraZeneca-ChAdOx1-nCoV-19 (AAP) vaccine, followed by a third PFZ vaccine and a haemodialysis cohort that had a mixture of two AZ or PFZ vaccines followed by a PFZ booster. Six months post second vaccine there was evidence of antibody waning with 58.9% of individuals in the HD cohort seropositive against Wuhan, 34.4% Delta and 62.2% Omicron strains. For the AAP cohort, equivalent figures were 62.5%, 45.8% and 91.7% and the PPP cohort 92.2%, 90% and 91.1%. Post third dose vaccination there were universal increases in seropositivity and median optical density. For the HD cohort, 98.8% were seropositive to the Wuhan strain, 97.6% against Delta and 100% against Omicron strains. For the PPP and AAP cohorts, 100% were seropositive against all 3 strains. Lastly, we examined the WHO NIBSC 20/136 standard and there was no loss of antibody binding to either VOC. Similarly, a dilution series of Sotrovimab (GSK) found this therapeutic monoclonal antibody bound similarly to all VOC. HighlightsO_LIIgG anti-SARS-CoV-2 Omicron spike glycoprotein antibody levels were high in 100% of health care workers (HCW), a general practice population considered clinically extremely vulnerable (CEV) and haemodialysis patients (HD) 4 weeks after a third SARS-CoV-2 vaccine dose (Pfizer-BioNtech-PFZ). C_LIO_LIFor both Delta and Omicron variant spike glycoproteins these antibody levels were highest in the CEV cohort who had previously received two doses of AstraZeneca ChAdOx1 nCoV-19 vaccine (AAP), lower in HCW who had previously received two doses of PFZ (PPP) and lowest in HD who had a mix of vaccines for the first and second dose C_LIO_LIPrior to this third vaccine dose and 6 months post second vaccine dose there was evidence of significant waning of antibodies against VOC. C_LI
RESUMO
BackgroundThe SARS-CoV-2 pandemic necessitated rapid and global responses across all areas of healthcare, including an unprecedented interest in serological immunoassays to detect antibodies to the virus. The dynamics of the immune response to SARS-CoV-2 is still not well understood and requires further investigation into the longevity of humoral immune response that is evoked due to SARS-CoV-2 infection. MethodsWe measured SARS-CoV-2 antibody levels in plasma samples from 880 people in Northern Ireland using Roche Elecsys Anti-SARS-CoV-2 IgG/IgA/IgM, Abbott SARS-CoV-2 IgG and EuroImmun IgG SARS-CoV-2 ELISA immunoassays to analyse immune dynamics over time. We undertook a laboratory evaluation for the UK-RTC AbC-19 rapid lateral flow immunoassay (LFIA), for the target condition of SARS-CoV-2 Spike protein IgG antibodies using a reference standard system to establish a characterised panel of 330 positive and 488 negative SARS-CoV-2 IgG samples. ResultsWe detected persistence of SARS-CoV-2 IgG up to 140 days (20 weeks) post infection, across all three laboratory-controlled immunoassays. On the known positive cohort, the UK-RTC AbC-19 lateral flow immunoassay showed a sensitivity of 97.58% (95.28%-98.95%) and on known negatives, showed specificity of 99.59% (98.53 %-99.95%). ConclusionsThrough comprehensive analysis of a cohort of pre-pandemic and pandemic individuals, we show detectable levels of IgG antibodies, lasting up to 140 days, providing insight to antibody levels at later time points post infection. We show good laboratory validation performance metrics for the AbC-19 rapid test for SARS-CoV-2 Spike protein IgG antibody detection in a laboratory based setting.