Letter to the Editor: COVID-19 Infections Do Not Change with Increasing Altitudes from 1,000 to 4,700 m

Abstract

C oronavirus disease (COVID-19) infection, after the first case reported in Wuhan, China, on December 31, 2019 and declared a pandemic by the World Health Organization in March 2020, has climbed by September 2nd to 26,076,572 cases and 864,162 deaths worldwide.Although it has been suggested that living at high altitude could decrease the rate of coronavirus transmission and mortality from COVID-19 (Arias-Reyes et al., 2020), new studies have not confirmed this protective effect. In fact, the case-fatality rate in Peru did not change with altitude (Segovia-Juarez et al., 2020).In the United States and Mexico, populations located >2,000 m have a higher total cumulative number of COVID-19 cases and a higher mortality rate attributable to COVID-19 than those located <1,500 m (Woolcott and Bergman, 2020). This study included data up to April 13, 2020, in the United States and up to May 13, 2020, in Mexico.A recent comprehensive review calls into question whether environmental factors, particularly ambient hypoxia, may be responsible at high altitude for reducing viral transmission and mortality due to COVID-19 (Pun et al., 2020). These conflicting results need further clarification and more current data. For this, we have assessed data from Peru, a country with one of the highest per capita number of infections and mortality rate worldwide.We used data of COVID-19 cases from 1,636 districts located from 5 to 4,705 m. The data set of COVID-19 cases (N = 535,946, from March 6 to August 15, 2020) was obtained from the National Open Data Platform (MINSA, 2020). Population and altitude data were gathered from National Institute of Information and Statistics (INEI, 2019), and combined with the aforementioned data set. This afforded altitude and district population information for 509,521 positive cases, representing people living at different altitudes, and providing the possibility of studying the effect of altitude with enough power to determine statistical significance.We considered three ranges: (1) altitudes <1,000 m, (2) altitudes between 1,000 and 2,500 m, and (3) altitudes

Altitude does not protect against SARS‐CoV‐2 infections and mortality due to COVID‐19

“…When all altitudes (2-4700 m) are assessed in a single analysis, an inversely proportional correlation with altitude is observed as reported in other studies (Castagnetto et al, 2020;Segovia-Juarez et al, 2020). This relationship is apparently an artifact as only this negative correlation is evident at altitudes between 0 and <1500 m. From 1500 to 4700 m, no association of positive cases with altitude is observed even though variables such as partial oxygen pressure, humidity, solar and cosmic radiation and humidity, and production of vitamin D change proportionally as altitude increase (Pun et al, 2020); further production of the angiotensin 2-converting enzyme, a carrier molecule for the entry of SARS-CoV-2 virus into the host cell, has also been suggested (Millet et al, 2021;Srivastava et al, 2020).…”

“…They suggest that the reported lower incidence and mortality of COVID-19 in high-altitude places observed by others (Stephens et al, 2021) remain to be confirmed. Stephens et al (2021) study two groups: one living in counties located at altitudes less than 914 m and the other at altitudes higher than 2133 m. Castagnetto et al (2020) assessing data at district level have demonstrated that at different altitude ranges from 0 to <1000 m, 1000 to 2500 m, and 2500 to 4700 m in Peru, the negative association with altitude was observed only in the group ranging from 0 to <1000 m. If analysis is done using all altitudes from 0 to 4700 m a negative association is observed between altitude and cases with SARS-CoV-2. Fernandes et al (2021) assessing 154 cities in Brazil located between 5 and 1135 m. They observe a negative association between altitude and cases of SARS-CoV-2.…”

COVID-19 Pandemic in Mountainous Areas: Impact, Mitigation Strategies, and New Technologies in Search and Rescue Operations

“…A study published early in the pandemic reported that COVID-19 had a lower impact on inhabitants of high-altitude areas in Asia and South America than of lowlands (Arias-Reyes et al, 2020 ). The hypothesis that high altitude populations are protected from severe effects of COVID-19 through a superior response to hypoxemia has been proven to be wrong (Castagnetto et al, 2020 ; Intimayta-Escalante et al, 2020 ; Joyce et al, 2020 ; Pun et al, 2020 ).…”

The Pathogenicity of COVID-19 Is Independent of Increasing Altitude: The Case of Colombia

“…At altitudes between 1,000 and 4,700 m, there was no significant association between altitude and incidence of infection. 4 An altitude gradient for protection against SARS-CoV-2 contagion could not be demonstrated.…”