Socioeconomic Vulnerabilities and the Intensity of RT-PCR SARS-CoV-2 Testing Efforts in the Public Health System in Sao Paulo State

Sousa, T. C. M. d.; Moreira, N. d. P.; Krieger, J.; Rosa, I. S. C.; Zamudio, M.; Veras, M. A. S. M.; Kemp, B.; Barberia, L.

Background The testing of infected persons with SARS-CoV-2 is one of the cornerstones to deploy pandemic control strategies. The public diagnostic effort is particularly important among the most vulnerable socioeconomic districts where the state is the sole health provider, such as Sao Paulo state, the Brazilian epicenter of the COVID-19 pandemic. Methods We developed an RT-PCR testing intensity effort index (RT-PCR TIEI) composed of seven indicators to assess the intensity testing efforts in the state of Sao Paulo. Each Regional Health Department (RHD) was scored using anonymized public data. We used dynamic time-series cross-sectional models to analyze the association between the RT-PCR TIEI in Sao Paulo state and its 17 RHDs from epidemiological weeks 10 to 35, and the proportion of the population living under a high level of socioeconomic vulnerability, dependent on public health service (SUS), per capita income, and population density. The regression models included an intercept and the lag of the RT-PCR TIEI, and standard errors were clustered by RHD. Findings On average, the RT-PCR TIEI score was 23.50. The maximum (47.06) was reached in week 11 and declined in subsequent weeks. The lowest score (17.65) was reached in week 25. In the long-run, socioeconomic vulnerability is negatively associated with RT-PCR TIEI (p-value=0.000, 95% CI -0.896, -0.816), with a higher proportion of the population dependent on SUS (p-value= 0.000, 95% CI -0.877, 0.808) and with population density (p-value=0.000, 95% CI -0.857; -0.806). Conclusion There was a decline in the state's testing intensity as the pandemic advanced, and the most socioeconomic vulnerable RHDs showed the lowest values where local public laboratory presence is a predictor of a higher RT-PCR TIEI score. Thus, the low RT-PCR TIEI and local laboratory capacity inequality may affect surveillance capability, especially for the most socioeconomic vulnerable population.