ABSTRACT
Background: SARS-CoV-2 has spread throughout the world, including areas located at high or very high altitudes. There is a debate about the role of high altitude hypoxia on viral transmission, incidence, and COVID-19 related mortality. This is the first comparison of SARS-CoV-2 viral load across elevations ranging from 0 to 4,300 m. Objective: To describe the SARS-CoV-2 viral load across samples coming from 62 cities located at low, moderate, high, and very high altitudes in Ecuador. Method: ology: An observational analysis of viral loads among nasopharyngeal swap samples coming from a cohort of 4,929 patients with a RT-qPCR test positive for SARS-CoV-2. Results: : The relationship between high and low altitude only considering our sample of 4,929 persons is equal in both cases and not significative (p-value 0.19). In the case of low altitude, adding the gender variable to the analysis, it was possible to find a significative difference between female and male gender (p-value 0.068). Considering initially gender and then altitude, it was possible to find a significative difference between high and low altitude for male gender (p-value 0.065). There is not enough evidence to state that viral load is affected directly by altitude range but adding a new variable as sex in the analysis shows that the presence of new variables influences the relationship of altitude range and viral load. Conclusions: : There is no evidence that viral load differs at altitude level when we consider only one measure. Using as reference the variable gender is possible to note that at low altitude there is a difference between female and male gender. There is not difference between gender at high altitude level. In the case of considering gender as reference variable, it was possible to find that high and low altitude are different for male gender an equal for female gender. Viral load not only depends on altitude range; it also is affected by other variables like sex.