SARS-CoV-2 Infection in Cities from the Southern Region of Bahia State, Brazil: Analysis of Variables Associated in Both Individual and Community Level

Abstract

The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), challenged public health systems worldwide. Individuals in low-income countries/regions are still at individual and community risk concerning inequality, sanitation, and economic conditions. Besides, during the pandemic, the transmission in municipalities and communities in the countryside and less developed regions kept viral spread and required structured and strengthened clinical and laboratory surveillance. Here, we present an observational, analytic, cross-sectional study conducted using secondary data from the Laboratório de Farmacogenômica e Epidemiologia Molecular (LAFEM)-Universidade Estadual de Santa Cruz (UESC), to evaluate individual and community factors associated to SARS-CoV-2 infection in outpatients from different cities from Southern Region of Bahia State, in Brazil. The data were collected between June 2021 and May 2022. The SARS-CoV-2 positivity by RT-qPCR was correlated with low socio-economic indicators, including the Human development index (HDI_c) and Average worker salary (AWSc). Besides, in general, females were less likely to test positive for SARS-CoV-2 (OR = 0.752; CI 95% 0.663-0.853; p < 0.0001), while brown individuals had more positivity for infection (p < 0.0001). In addition, those who had clinical symptoms were more likely to test positive for SARS-CoV-2 (OR = 6.000; CI 95% 4.932-7.299; p < 0.0001). Although dry cough, headache, and fever were the most frequent, loss of taste (OR = 5.574; CI 95% 4.334-7.186) and loss of smell (OR = 6.327; CI 95% 4.899-8.144) presented higher odds ratio to be positive to SARS-CoV-2 by RT-qPCR. Nonetheless, the distribution of these characteristics was not homogenous among the different cities, especially for age and gender. The dynamic of SARS-CoV-2 positivity differed between cities and the total population and reinforces the hypothesis that control strategies for prevention needed to be developed based on both individual and community risk levels to mitigate harm to individuals and the health system.

Keywords: COVID-19; SARS-CoV-2; community risk; epidemiology; risk factor; socio-economic status.

Figure 1

Geographical distribution of SARS-CoV-2 infections at the community level in cities from the Southern Region of Bahia State in Brazil. (A) The geographical location of Bahia State (highlighted in red) in Brazilian territory. (B) The territorial distribution of BA State; cities from Southern BA State included in the study are highlighted in red. (C) Demand index (D_i—yellow gradient) and (D) Positivity index (P_i—green gradient) of SARS-CoV-2 from each city included in the study are presented. (E) Correlation matrix of the community risk level. The value inside cells indicates the Person correlation. Asterix in the cells indicates significative p values with p < 0.05. D_i, Demand index; P_i, Positivity index; HDI_c, Human development index; AWS_c, Average worker salary; SR_6–14, Schooling rate between 6–14 years old; *** indicated the very low number of samples to calculate P_i.

Figure 2

Population pyramid frequency from individuals tested for SARS-CoV-2 infection. (A) SARS-CoV-2 positive; (B) SARS-CoV-2 negative; (C) total population; (D) overlapping curves for population pyramid frequency.

Figure 3

SARS-CoV-2 infection at the community level in cities from the Southern Region of Bahia State. Frequency of SARS-CoV-2 infection in Bahia cities according to gender. Female (green); male (blue); SARS-CoV-2 positive (+); SARS-CoV-2 negative (−); the total number (n) of individuals in each city is presented in the orange line; OR, odds ratio; values in parentheses indicate interval confidence 95% (CI 95%).

Figure 4

Age distribution by city in the Southern Region of Bahia State. Mann-Whitney test. Data are presented as mean ± standard error of the mean (S.E.M.). Vales of p < 0.05 were considered statistically significant. * p < 0.05; *** p < 0.001; **** p < 0.0001.