High SARS-CoV-2 seroprevalence in persons experiencing homelessness and shelter workers from a day-shelter in São Paulo, Brazil

Abstract

Brazil presents one of the highest COVID-19 death tolls in the world. The initial SARS-CoV-2 epicenter was São Paulo city. As of 2019, the homeless population of São Paulo city was estimated at 24,344 individuals, the largest national homeless population. The present study aimed to concomitantly assess the molecular and serological prevalence and associated risk factors of SARS-CoV-2 infection in a homeless population and related shelter workers from a day-shelter. Serum samples, nasopharyngeal and oropharyngeal swabs of persons who are homeless and shelter workers collected from August 25th to 27th, 2020 were tested for the presence of anti-SARS-CoV-2 IgM and IgG antibodies by ELISA and SARS-CoV-2 RNA by RT-qPCR, respectively. All swab samples tested negative by RT-qPCR. Seropositivity of IgM and IgG was 5/203 (2.5%) and 111/203 (54.7%) in persons who are homeless, and 5/87 (5.7%) and 41/87 (47.1%) in shelter workers, respectively, with no statistical differences between groups. The high seroprevalence found herein indicates early environmental and urban spreading of SARS-CoV-2, associated with sociodemographic and economic vulnerability.

Ku-gaa-gii pimitizi-win, the COVID-19 cohort study of people experiencing homelessness in Toronto, Canada: a study protocol

“…To date, most studies describing incidence or prevalence of COVID-19 among PEH have been cross-sectional in design, many focussing on a convenience sample of shelters during the first or second waves (from March to December 2020). As a result, estimates from these studies vary widely depending on setting, timing and preventive measures in place,13–25 with variability primarily determined by whether the settings, in most cases emergency shelters, were experiencing an outbreak 13 15 16 19 26. One study using a longitudinal design estimated 6% prevalence in summer 2020, increasing to 18.9% within 90 days (coinciding with the early part of the second wave) 27.…”

Prevalence and predictors of anti-SARS-CoV-2 serology in a highly vulnerable population of Rio de Janeiro: A population-based serosurvey

“… 39 Additionally, a survey conducted with homeless persons in a large day-shelter in São Paulo city (Southeast region of Brazil) found a 54·7% prevalence in August 2020. 40 In a vulnerable area in Sao Paulo city (Paraisópolis), a 43·8% prevalence was found among individuals aged 18 years or older ( n = 272) (from September to December 2020). 41 Moreover, a prospective cohort study conducted in the same neighbourhood as our study estimated the incidence of COVID-19 during four waves (from May 2020 to Nov 2021) and found that the incidence was much higher than previously reported by similar studies in the US and that the incidence was the highest in the first wave (May through November 2020).…”

Serosurvey of anti-Toxocara canis antibodies in people experiencing homelessness and shelter workers from São Paulo, Brazil

“…Although several risk factors have been reportedly associated with toxocariasis, including being male, youngster, having contact with dogs, cats, soil, consuming raw meat, and drinking untreated water [ 6 ], none was statistically associated with the presence of anti- Toxocara antibodies. Such outcomes may be due to low sampling or high sample heterogeneity, or more likely, the skewness of the homeless population, mostly males, adults, and reportedly drug users [ 33 , 34 ]. Not surprisingly, the predominance of males in the homeless population observed here has already been reported in Canada (273/455; 60%) [ 35 ], Nicaragua (62/82; 75.7) (9), and Brazil (635/701; 90.7%) [ 36 ].…”