LAUSR

Introduction Migrants, especially those in temporary accommodations like camps and shelters, might be a vulnerable population during the COVID-19 pandemic, but little is known about the impact of the pandemic in these settings in low-income and middle-income countries. We assessed SARS-CoV-2 seropositivity and RNA prevalence, the correlates of seropositivity (emphasising socially determined conditions), and the socioeconomic impacts of the pandemic among migrants living in shelters in Tijuana, a city on the Mexico-US border. Methods We conducted a cross-sectional, non-probability survey of migrants living in shelters in Tijuana in November–December 2020 and February–April 2021. Participants completed a questionnaire and provided anterior nasal swab and blood samples for detection of SARS-CoV-2 RNA and antibodies (IgG and IgM), respectively. We explored whether SARS-CoV-2 infection was associated with sociodemographic and migration-related variables, access to sanitation, protective behaviours and health-related factors. Results Overall, 481 participants were enrolled, 67.7% from Northern Central America, 55.3% women, mean age 33.2 years. Seven (1.5%) participants had nasal swabs positive for SARS-CoV-2 RNA and 53.0% were SARS-CoV-2 seropositive. Avoiding public transportation (OR 0.59, 95% CI 0.39 to 0.90) and months living in Tijuana (OR 1.06, 95% CI 1.02 to 1.10) were associated with seropositivity. Sleeping on the streets or other risky places and having diabetes were marginally associated with seropositivity. Most participants (90.2%) had experienced some socioeconomic impact of the pandemic (eg, diminished income, job loss). Conclusion Compared with results from other studies conducted in the general population in Mexico at a similar time, migrants living in shelters were at increased risk of acquiring SARS-CoV-2, and they suffered considerable adverse socioeconomic impacts as a consequence of the pandemic. Expanded public health and other social support systems are needed to protect migrants from COVID-19 and reduce health inequities.