Effectiveness of a COVID-19 Testing Outreach Intervention for Latinx Communities: A Cluster Randomized Trial

Abstract

Importance: Latinx individuals have been disproportionately affected during the COVID-19 pandemic caused by the spread of SARS-CoV-2. It is imperative to evaluate newly developed preventive interventions to assess their effect on COVID-19 health disparities.

Objective: To examine the effectiveness of a culturally tailored outreach intervention designed to increase SARS-CoV-2 testing rates among Latinx populations.

Design, setting, and participants: In this cluster randomized trial performed from February 1 to August 31, 2021, in community settings in 9 Oregon counties, 38 sites were randomized a priori (19 to the community health promoters intervention and 19 to outreach as usual wait-listed controls). Thirty-three sites were activated. A total of 394 SARS-CoV-2 testing events were held and 1851 diagnostic samples collected, of which 919 were from Latinx persons.

Interventions: A culturally informed outreach program was developed that made use of promotores de salud (community health promoters) to increase Latinx SARS-CoV-2 testing. Strategies addressed barriers by disseminating information on testing events in English and Spanish, mitigating misinformation, and increasing trust.

Main outcomes and measures: The primary outcomes were the count of sample tests from Latinx persons and the sampled proportion of the Latinx populace. Site-level covariates included census tract Latinx populace, nativity (number of US-born individuals per 100 population), median age, and income inequality. Time-varying covariates included number of new weekly SARS-CoV-2-positive cases and percentage of vaccine coverage at the county level.

Results: A total of 15 clusters (sites) were randomized to the control group and 18 to the community health promoters group. A total of 1851 test samples were collected, of which 995 (53.8%) were from female participants and 919 (49.6%) were from Latinx individuals. The intervention tested 3.84 (95% CI, 2.47-5.97) times more Latinx individuals per event than controls (incident rate ratio, 0.79; 95% CI, 0.46-1.34; Cohen d = 0.74; P < .001). The intervention was associated with a 0.28 increase in the proportion of Latinx populace being tested compared with control sites for the dependent variable scaled as the proportion of the Latinx populace ×100, or a 0.003 proportion of the raw populace count. The use of a standardized scaling of the proportion of Latinx individuals showed that the relative percentage increase was 0.53 (95% CI, 0.21-0.86) in the intervention sites compared with controls, representing a medium effect size.

Conclusions and relevance: To our knowledge, this was the first randomized evaluation of an outreach intervention designed to increase SARS-CoV-2 testing among Latinx populations. Findings could be used to implement strategies to reduce other health disparities experienced by these groups.

Trial registration: ClinicalTrials.gov Identifier: NCT04793464.

Figure 1.. Study Flow Diagram of Enrollment, Randomization Sites, and Follow-up of Testing Samples for Cluster Randomized Trial

ITT indicates intention-to-treat; OAU, outreach as usual.

Figure 2.. Intervention Effect Sizes for the Primary Outcomes

A, Model-based estimates of Promotores de Salud intervention effect on predicted numbers of Latinx individuals tested per testing event (incident rate ratio = 3.84; 95% CI, 2.47-5.97; Cohen d = 0.74). B, Community health promoters intervention effect on proportion of Latinx populace (33 sites, 394 testing events, and 1851 individuals; effect size = 0.53). Error bars indicate 95% CIs.

Figure 3.. Time-Varying Effect of COVID-19 Transmission and Vaccination Coverage

A. Model-based independent time-varying effects of new COVID-19 county cases in the prior week. B. Effect of percentage of county vaccine coverage in the prior week on the estimated numbers of Latinx individuals tested per testing event (33 sites, 394 testing events, and 1851 individuals). Shaded areas indicate 95% CIs.