Hybrid immunity from severe acute respiratory syndrome coronavirus 2 infection and vaccination in Canadian adults: A cohort study.

Background: Few national-level studies have evaluated the impact of 'hybrid' immunity (vaccination coupled with recovery from infection) from the Omicron variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods: From May 2020 to December 2022, we conducted serial assessments (each of ~4000-9000 adults) examining SARS-CoV-2 antibodies within a mostly representative Canadian cohort drawn from a national online polling platform. Adults, most of whom were vaccinated, reported viral test-confirmed infections and mailed self-collected dried blood spots (DBSs) to a central lab.

Excess deaths in China during SARS-CoV-2 viral waves in 2022-2023.

Background: The extent to which the Omicron variant of SARS-CoV-2 raised death rates in China during its viral wave of December 2022-January 2023 remains largely undocumented.

Methods: We worked with an established national survey organization to survey 8,004 adults in all 31 administrative areas of China to ask about deaths in families since January 2020. We examined age-specific death rates, focusing on deaths above age 60 years, and at 15-59 years.

Ethnic minority, immigrants, and Indigenous people's well-being disparities in Canada during the COVID-19 pandemic: The mediating role of threat perceptions.

The COVID-19 pandemic's differential impact on ethnic minorities, immigrants, and Indigenous people (e.g., mortality and infection rate, as well as psychological well-being) may exacerbate existing disparities.

Assessment of SARS-CoV-2 Seropositivity During the First and Second Viral Waves in 2020 and 2021 Among Canadian Adults.

Importance: The incidence of infection during SARS-CoV-2 viral waves, the factors associated with infection, and the durability of antibody responses to infection among Canadian adults remain undocumented.

Objective: To assess the cumulative incidence of SARS-CoV-2 infection during the first 2 viral waves in Canada by measuring seropositivity among adults.

Design, Setting, And Participants: The Action to Beat Coronavirus study conducted 2 rounds of an online survey about COVID-19 experience and analyzed immunoglobulin G levels based on participant-collected dried blood spots (DBS) to assess the cumulative incidence of SARS-CoV-2 infection during the first and second viral waves in Canada.

COVID discrimination experience: Chinese Canadians' social identities moderate the effect of personal and group discrimination on well-being.

Objective: The coronavirus disease (COVID-19) pandemic has amplified preexisting racism and xenophobia. In this study, we investigated (a) whether perceived personal and group discrimination make distinct contributions to Chinese Canadians' negative affect and concern that the heightened discrimination they experienced during the pandemic will continue after the pandemic; (b) whether Canadian and Chinese identities and social support moderate the effect of discrimination on this concern; and (c) whether race-based rejection sensitivity (RS) explains why each type of discrimination predicts negative affect and expectation of future discrimination.

Method: A sample of Chinese Canadian adults across Canadian provinces ( = 516; = 42.

Predictors of self-reported symptoms and testing for COVID-19 in Canada using a nationally representative survey.

Random population-based surveys to estimate prevalence of SARS-CoV2 infection causing coronavirus disease (COVID-19) are useful to understand distributions and predictors of the infection. In April 2020, the first-ever nationally representative survey in Canada polled 4,240 adults age 18 years and older about self-reported COVID experience in March, early in the epidemic. We examined the levels and predictors of COVID symptoms, defined as fever plus difficulty breathing/shortness of breath, dry cough so severe that it disrupts sleep, and/or loss of sense of smell; and testing for SARS-CoV-2 by respondents and/or household members.