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. 2022 Sep 8;12(9):e062187.
doi: 10.1136/bmjopen-2022-062187.

Cohort profile: S top the Spread Ottawa (SSO) - a community-based prospective cohort study on antibody responses, antibody neutralisation efficiency and cellular immunity to SARS-CoV-2 infection and vaccination

Erin Collins  1   2 , Yannick Galipeau  3 , Corey Arnold  3 , Cameron Bosveld  4 , Aliisa Heiskanen  5   2 , Alexa Keeshan  5   2 , Kiran Nakka  3   6 , Khatereh Shir-Mohammadi  3 , Frederic St-Denis-Bissonnette  4 , Laura Tamblyn  4 , Agatha Vranjkovic  4 , Leah C Wood  4 , Ronald Booth  7   8 , C Arianne Buchan  9   10 , Angela M Crawley  3   4   11   12 , Julian Little  5   2   11   13 , Michaeline McGuinty  9   10 , Raphael Saginur  9   10   14 , Marc-André Langlois  3   11   12 , Curtis L Cooper  2   9   10   11   12
Affiliations

Cohort profile: S top the Spread Ottawa (SSO) - a community-based prospective cohort study on antibody responses, antibody neutralisation efficiency and cellular immunity to SARS-CoV-2 infection and vaccination

Erin Collins et al. BMJ Open. .

Abstract

Purpose: To investigate the robustness and longevity of SARS-CoV-2 immune responses conferred by natural infection and vaccination among priority populations such as immunocompromised individuals and people with post-acute sequelae of COVID-19 in a prospective cohort study (Stop the Spread Ottawa-SSO) in adults living in the Ottawa region. In this paper, we describe the study design, ongoing data collection and baseline characteristics of participants.

Participants: Since October 2020, participants who tested positive for COVID-19 (convalescents) or at high risk of exposure to the virus (under surveillance) have provided monthly blood and saliva samples over a 10-month period. As of 2 November 2021, 1026 adults had completed the baseline survey and 976 had attended baseline bloodwork. 300 participants will continue to provide bimonthly blood samples for 24 additional months (ie, total follow-up of 34 months).

Findings to date: The median age of the baseline sample was 44 (IQR 23, range: 18-79) and just over two-thirds (n=688; 67.1%) were female. 255 participants (24.9%) had a history of COVID-19 infection confirmed by PCR and/or serology. Over 600 participants (60.0%) work in high-risk occupations (eg, healthcare, teaching and transportation). 108 participants (10.5%) reported immunocompromising conditions or treatments at baseline (eg, cancer, HIV, other immune deficiency, and/or use of immunosuppressants).

Future plans: SSO continues to yield rich research potential, given the collection of pre-vaccine baseline data and samples from the majority of participants, recruitment of diverse subgroups of interest, and a high level of participant retention and compliance with monthly sampling. The 24-month study extension will maximise opportunities to track SARS-CoV-2 immunity and vaccine efficacy, detect and characterise emerging variants, and compare subgroup humoral and cellular response robustness and persistence.

Keywords: COVID-19; epidemiology; immunology; infectious diseases; public health; virology.

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Conflict of interest statement

Competing interests: None declared.

Figures

Figure 1
Figure 1
Procedures for Stop the Spread Ottawa (SSO) study participants, baseline to month 10 and extension to month 34. PBMC, peripheral blood mononuclear cell.
Figure 2
Figure 2
Flow diagram of enrolled participants, as of 2 November 2021.
See this image and copyright information in PMC

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