The first SARS-CoV-2 pandemic has affected most countries causing hundreds of thousands of deaths. Evolution of the pandemic may involve endemicity with or without significant secondary waves. We observed that disease severity (p=0.006) and duration of symptoms (p<0.001) declined over time in an isolated rural community. This decline was not driven by changes in patient age structure nor by changes in temperature or precipitations. The underlying mechanism may be relevant for COVID-19 management.