ABSTRACT
Background: People who inject drugs (PWID) may be at a greater risk of SARS-CoV-2 infection and COVID-19 due to socio-structural inequities, high-risk behaviors and comorbidities;however, PWID have been underrepresented in case-based surveillance due to lower access to testing. We characterize temporal trends and correlates of SARS-CoV-2 seroprevalence among a community-based sample of current and former PWID. Method(s): A cross-sectional study was conducted among participants in the AIDS Linked to the IntraVenous Experience (ALIVE) study-a community-based cohort of adults with a history of injection drug use in Baltimore, Maryland. Participants' first serum sample collected at routine study visits between December 2020 and July 2022 was assayed for antibodies to the nucleocapsid (N) (past infection) and spike-1 (S) (past infection and/or vaccination) proteins using the MSD V-Plex Panel 2 IgG SARS-CoV-2 assay. For each correlate, we estimated adjusted prevalence ratios (PR) via separate Poisson regression models adjusted for calendar time, age, sex and race. Result(s): Of 561 participants, the median age was 59 years (range=28-77), 35% were female, 84% were Black, 36% were living with HIV (97% on ART), and 55% had received >=1 COVID-19 vaccine dose. Overall, anti-N and anti-S prevalence was 26% and 63%, respectively. Prevalence of anti-N increased from 23% to 40% between December 2020-May 2021 and December 2021-July 2022, with greater increases in the prevalence of anti-S from 34% to 86% over the same period (Figure). Being employed (PR=1.53 [95%CI=1.11-2.11]) and never being married (PR=1.40 [0.99-1.99]) were associated with a higher prevalence of anti-N, while female sex (PR=0.75 [0.55-1.02]) and a history of cancer (PR=0.40 [0.17-0.90]) were associated with a lower prevalence of anti-N. Younger age, female sex (PR=0.90 [0.80-1.02]), and homelessness (PR=0.78 [0.60-0.99]) were associated with a lower prevalence of anti-S. Although HIV infection was not associated with anti-N, it was associated with a higher prevalence of anti-S (PR=1.13 [1.02-1.27]). Substance use was not associated with anti-N or anti-S. Conclusion(s): Anti-N and anti-S levels increased over time, suggesting cumulative increases in SARS-CoV-2 incidence of infection and vaccination among PWID;however, disparities in seroprevalence remain. Younger and female PWID and those experiencing homelessness were less likely to be anti-S positive, suggesting programs should aim to improve vaccination coverage in such vulnerable populations.