Structural factors contributing to SARS-CoV-2 infection risk in the urban slum setting

Abstract

Background The structural environment of urban slums, including physical, demographic and socioeconomic attributes, renders inhabitants more vulnerable to SARS-CoV-2 infection. Yet, little is known about the specific determinants that contribute to high transmission within these communities. Methods and findings We performed a serosurvey of an established cohort of 2,035 urban slum residents from the city of Salvador, Brazil between November 2020 and February 2021, following the first COVID-19 pandemic wave in the country. We identified high SARS-CoV-2 seroprevalence (46.4%, 95% confidence interval [CI] 44.3-48.6%), particularly among female residents (48.7% [95% CI 45.9-51.6%] vs. 43.2% [95% CI 39.8-46.6%] among male residents), and among children (56.5% [95% CI 52.3-60.5%] vs. 42.4% [95% CI 39.9-45.0%] among adults). In multivariable models that accounted for household-level clustering, the odds ratio for SARS-CoV-2 seropositivity among children was 1.96 (95% CI 1.42-2.72) compared to adults aged 30-44 years. Adults residing in households with children were more likely to be seropositive; this effect was particularly prominent among individuals with age 30-44 and 60 years or more. Women living below the poverty threshold (daily per capita household income <$1.25) and those who were unemployed were more likely to be seropositive. Conclusions During a single wave of the COVID-19 pandemic, cumulative incidence as assessed by serology approached 50% in a Brazilian urban slum population. In contrast to observations from industrialized countries, SARS-CoV-2 incidence was highest among children, as well as women living in extreme poverty. These findings emphasize the need for targeted interventions that provide safe environments for children and mitigate the structural risks posed by crowding and poverty for the most vulnerable residents of urban slum communities.

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

“…In the metropolitan area of Vitória (also in the Southeast region of Brazil), in June 2020, the estimated prevalence among individuals aged two years or older living in slums was 12·1% ( n= 714) 38 ; while a study that included 2,035 urban slum residents Salvador city (Northeast region of Brazil) observed a 46·4% prevalence (from November 2020 to February 2021). 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).…”

Social determinants of adult COVID-19 vaccine acceptance and uptake in a Brazilian urban informal community: a longitudinal time-to-event study

“…This is surprising in light of the prior data showing that, throughout the city, men had higher vaccine confidence than women, and non-White women with fewer years of education were more likely to express vaccine hesitancy 18 . Such a result may be related to the high level of COVID-19 exposure experienced by women in the community 20 , which could increase their propensity to seek vaccination. However, local providers also express that men exhibit less healthcare-seeking behavior beyond just vaccination.…”

“…This community is in a peripheral area that grew informally in the 1970s after the expulsion of poor populations from the city center. The need to rely on public transit and high residential crowding have made residents especially vulnerable to COVID-19 infection 20 . However, as of 2020, intent to take the vaccine among residents was only 66.0% 21 , lower than the national estimate of 85.4% 21 or the city-wide estimate for Salvador of 81.4% 18 .…”