Clinical and Economic Impact of COVID-19 and Serologic Protection among Farm Workers: Results from the Guatemala Agricultural Workers and Respiratory Illness Impact (AGRI) Study

ABSTRACT

Background. In the Guatemala AGricultural workers and Respiratory Impact (AGRI) study, we evaluated the clinical and socioeconomic burdens of respiratory disease in a cohort of Guatemalan banana farm workers. Methods. All eligible workers were offered enrollment from June 15-December 30, 2020, and annually, then followed for influenza-like illnesses (ILI) through 1) selfreporting to study nurses, 2) sentinel surveillance at health posts, and 3) absenteeism. Workers with ILI submitted nasopharyngeal swabs for influenza, RSV, and SARS-CoV-2 testing, then completed surveys at days 0, 7, and 28. Enrollment and acute-illness serum samples were tested for anti-SARS-CoV-2 nucleocapsid IgG (anti-N, Roche Elecsys ), and neutralizing antibodies (NAb) were tested in a subset using a lentivirus-based pseudovirion assay. Results. Through October 10, 2021, 1,833 workers were enrolled. The majority were male (84%), young (mean 31 years), and healthy (< 13% had comorbidity). Through October 10, 2021, 1,833 workers developed 169 ILIs (12.0/100 person-years) and 43 (25.4%) of these ILIs were laboratory-confirmed SARS-CoV-2 (3.1/100 person-years). Workers with SARS-CoV-2-positive ILI reported more anosmia (p< 0.01), dysgeusia (p< 0.01), difficulty concentrating (p=0.01), and irritability (p=0.01), and greater clinical and well-being severity scores (Flu-iiQ) than testnegative ILIs (Fig 1);they also had greater absenteeism (p< 0.01) and lost income (median US$127.1, p< 0.01). Among 1334 workers enrolled in 2020, 616 (46.2%) had anti-N IgG suggestive of prior SARS-CoV-2 infection. COVID-19 incidence density for IgG-seropositive workers was 0.4/100 Person Years (PY), lower than those who were seronegative (2.3/100 PY) (Fig 2). At enrollment, anti-N IgG titers in serum correlated with neutralizing antibody titers (R2 =0.26, p< 0.0001). Notably, in < 6 months from enrollment, most workers with follow-up NAb testing (65/77, 84%) exhibited a 95% decrease in neutralizing antibody titers. Conclusion. Guatemalan farm workers suffered a significant burden of COVID-19, including more severe clinical and economic outcomes than other respiratory illnesses. Ongoing vaccination programs and longitudinal serology will provide additional insight into long-term immunity.