Table 1.
Ecological studies reporting NO association between selenium and COVID-19.
| First Author, Year [Ref] | Country | Study Period | Consulted Databases for Selenium Levels | Consulted Databases for COVID-19 Incidence |
|---|---|---|---|---|
| Galmés, 2020 [27] | Spain, Belgium, Italy, UK, Portugal, France, the Netherlands, Germany, Denmark, Finland |
May 2020 | Essential nutrients intake for the maintenance of the immune system, endorsed by the European Food Safety Authority | Worldometers.info COVID-19 epidemiological indicators |
| Galmés, 2022 [28] | Spain | Not specified | Micronutrient intake in Spain obtained from the household Spanish report, containing pre-pandemic (2019) consumption data (Ministry of Agriculture, Fisheries and Food) | Epidemiological COVID-19 Spanish data from the Centre for the Coordination of Health Alerts and Emergencies of the Ministry of Health (Update No. 235 of the Coronavirus Disease (COVID-19) on 23 October 2020) |
| Ermakov, 2022 [29] | Russia | September 2020–January 2021 | Selenium concentration in herbaceous plants (cuts), surfaces and groundwaters, annual precipitations, and incidence of white muscle disease in farm livestock | Coronavirus situations in Russia on 29 January 2021, and on 5 September 2020, from www.koronavirustoday.ru/news/russia. |
| Chen, 2022 [30] | USA | 8 October 2020–25 March 2021 | Geochemical concentrations of selenium from the National Geochemical Survey 1997–2009 | Epidemiological data on the case fatality rate of COVID-19 in USA, accessed using the COVID-19 interactive map from the “John Hopkinson” University |
| Nimer, 2022 [31] | Jordan | March–July 2021 | Selenium supplementation data collected via a self-administered questionnaire using a Google form | COVID-19 disease symptoms and hospitalization status data collected via a self-administered questionnaire using a Google form |