Thread by @dockaurG

Imp Thread: public health fallacy to claim popn #SARSCoV2 IgG serology tests capture all pts recovered from #COVID19: grossly UNDERestimates % popn that was asymptomatic & recovered. Key arms of immune response to #SARSCoV2: humoral with antibodies & cell-mediated with T-cells

https://twitter.com/dockaurG/status/1261747239967391746

2/ Current public health method to estimate population immunity to #SARSCoV2 from recovered asymptomatic #COVID19 ppl uses serology tests to detect IgG antibodies: this only captures humoral immunity. Currently no widely available testing kit for T-cell immunity to #SARSCoV2

3/ Pts mount strong T-cell immune responses to #coronaviruses. Published Cell research & studies on recovered #COVID19 pts w/immunodeficiency disorders w/inability to mount B-cell responses to #SARSCoV2 reveal B-cell antibody responses not strictly required to overcome COVID-19

4/ Similarly published studies on pts more than ten years after they recovered from #SARS infection reveal these patients still have strong long-term #SARSCoV1 immunity due to strong persistence of SARS-specificity CD8+ cytotoxic T-cell memory cells

5/ Based on Cell study: #COVID19 recovered pts had strong T-cell immune responses: 100% made CD4+ Tcells. 70% made CD8+ Tcells. ~50% of pts who never had #COVID19 still had pre-existing cross-protective T-cell immunity to #SARSCoV2 from prev exposure to common cold #coronaviruses

6/ Govts & public health grossly underestimating both pre-existing cross-protective immunity to #SARSCoV2 from prior exposure to common cold #coronaviruses & % of asymptomatic pts recovered from #COVID19 in pop’n b/c no widely avail testing kit to detect #SARSCoV2 T-cell immunity