Thread by @SCOTTeHENSLEY

1/ Our paper showing that ~20% of humans possessed non-neutralizing antibodies against SARS-CoV-2 prior to the COVID-19 pandemic was published today @CellCellPress.

cell.com/cell/fulltext/…

2/ I described this study when we released this as a preprint in November:

https://twitter.com/SCOTTeHENSLEY/status/1326216898812506113

3/ We found that most of us are infected with seasonal coronaviruses by age 4-5 (similar to flu).

4/ We found that 20% of us had antibodies that targeted non-neutralizing sites on SARS-CoV-2 prior to the pandemic. We found no relationship between year of birth and presence of pre-pandemic antibodies.

5/ We were able to measure Abs in a unique cohort: individuals who donated samples prior to the pandemic who subsequently went on to become infected with SARS-CoV-2. Pre-pandemic cross-reactive SARS-CoV-2 Abs did not correlate with SARS-CoV-2 protection.

6/ Interestingly, we found that Abs reactive to the S2 domain of OC43 (a seasonal coronavirus) are boosted upon SARS-CoV-2 infection, but the magnitude of boost does not appear to be associated with disease outcome.

7/ Sometimes it is good when a paper provides more questions than answers. There is still so much to figure out. Recent prior seasonal coronavirus infections are associated with less COVID-19 disease (Sagar 2020), but our study suggest that this protection is not from antibody.

8/ We concluded the paper with this: “It is possible that pre-existing cellular immunity might play an important role in the context of pandemic viruses that only share non-neutralizing antibody epitopes with previously circulating viral strains.”

9/ Congrats to @EMAndersonPhD, Eileen Goodwin, Anurag Verma and the whole team @PennMedicine. Many of these experiments were completed in the spring/2020 as we tested new serological assays and I will be forever grateful for my great team who worked in the face of a pandemic.