ABSTRACT
Background: Cancer p represent a high-risk population for severe COVID-19. Cancer-associated immunosuppression may hinder in the development of anti-SARS-CoV-2 antibodies. Methods: Data regarding baseline characteristics (age, cancer type, cancer activity, cancer treatment), COVID-19 infection and anti-SARS-CoV-2 IgG were collected from p with solid tumors who tested positive for COVID-19 (PCR+) between 10th March and 9th December 2020 at Catalan Institute of Oncology. We prospectively assessed anti-SARS-CoV-2 IgG seroprevalence at different timepoints (<2, 2-6, >6 months [m] since first PCR+) and explored factors associated with long-term IgG positivity. Results: Out of 79 registered p, 19 died without IgG testing (all of them <3 months after a PCR+), and 8 refused to participate, leaving 52 tested for IgG. Tested and not-tested p were similar according to baseline characteristics, cancer treatment and COVID-19. At the 1st timepoint, 19/23p were IgG+;at the 2nd, 29/33p were IgG+ and 1 inconclusive;at the 3rd timepoint, 18/22 were IgG+ (median time from PCR + to 3rd timepoint determination was 9.4 m (Interquartile range [IQR]: 8.5-9.7). Importantly, 1 p changed from IgG+ (2nd timepoint) to IgG- (3rd timepoint), and 1 inconclusive result (2nd timepoint) changed to negative (3rd timepoint). Potential factors associated to IgG+ >6 m are shown in the table. [Formula presented] Conclusions: High seroprevalence of anti-SARS-CoV-2 IgG was observed at several timepoints after COVID-19 diagnosis in solid tumor p. P with IgG+ at >6 m were older, and more likely to have required hospitalization and oxygen during prior COVID-19 in comparison to IgG- p >6m, suggesting that infection severity may promote durable immunity. Frequency of active cancer and active chemotherapy at COVID-19 diagnosis were higher among p with IgG- >6m, suggesting deeper immunosupression. Legal entity responsible for the study: The authors. Funding: Has not received any funding. Disclosure: E. Felip: Financial Interests, Personal, Other: Pfizer;Financial Interests, Personal, Other: Lilly;Financial Interests, Personal, Other: Eisai;Financial Interests, Personal, Other: Novartis;Financial Interests, Personal, Sponsor/Funding: Pfizer. M. Romeo Marin: Financial Interests, Personal, Advisory Board: MSD;Financial Interests, Personal, Advisory Board: MSK;Financial Interests, Personal and Institutional, Other: MSD;Financial Interests, Personal and Institutional, Principal Investigator: AZ;Financial Interests, Personal and Institutional, Principal Investigator: GSK Tesaro;Financial Interests, Personal and Institutional, Principal Investigator: Merck. All other authors have declared no conflicts of interest.