ABSTRACT
Grimm, Mirjam, Lucie Ziegler, Annina Seglias, Maamed Mademilov, Kamila Magdieva, Gulzada Mirzalieva, Aijan Taalaibekova, Simone Suter, Simon R. Schneider, Fiona Zoller, Vera Bissig, Lukas Reinhard, Meret Bauer, Julian Müller, Tanja L. Ulrich, Arcangelo F. Carta, Patrick R. Bader, Konstantinos Bitos, Aurelia E. Reiser, Benoit Champigneulle, Damira Ashyralieva, Philipp M. Scheiwiller, Silvia Ulrich, Talant M. Sooronbaev, Michael Furian, and Konrad E. Bloch. SARS-CoV-2 Transmission during High-Altitude Field Studies. High Alt Med Biol. 00:00-00, 2024. Background: Throughout the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic, virus transmission during clinical research was of concern. Therefore, during high-altitude field studies performed in 2021, we took specific COVID-19 precautions and investigated the occurrence of SARS-CoV-2 infection. Methods: From May to September 2021, we performed studies in patients with chronic obstructive pulmonary disease (COPD) and in healthy school-age children in Kyrgyzstan in high-altitude facilities at 3,100 m and 3,250 m and at 760 m. The various implemented COVID-19 safety measures included systematic SARS-CoV-2 rapid antigen testing (RAT). Main outcomes were SARS-CoV-2-RAT-positive rate among participants and staff at initial presentation (prevalence) and SARS-CoV-2-RAT-positive conversion during and within 10 days after studies (incidence). Results: Among 338 participants and staff, SARS-CoV-2-RAT-positive prevalence was 15 (4.4%). During mean ± SD duration of individual study participation of 3.1 ± 1.0 day and within 10 days, RAT-positive conversion occurred in 1/237(0.4%) participants. Among staff working in studies for 31.5 ± 29.3 days, SARS-CoV-2-RAT-positive conversion was 11/101(10.9%). In all 338 individuals involved in the studies over the course of 15.6 weeks, the median SARS-CoV-2-RAT-positive incidence was 0.00%/week (quartiles 0.00; 0.64). Over the same period, the median background incidence among the total Kyrgyz population of 6,636 million was 0.06%/week (0.03; 0.11), p = 0.013 (Wilcoxon rank sum test). Conclusions: Taking precautions by implementing specific safety measures, SARS-CoV-2 transmission during clinical studies was very rare, and the SARS-CoV-2 incidence among participants and staff was lower than that in the general population during the same period. The results are reassuring and may help in decision-making on the conduct of clinical research in similar settings.
ABSTRACT
STUDY OBJECTIVES: Newcomers at high altitude (> 3,000 m) experience periodic breathing, sleep disturbances, and impaired cognitive performance. Whether similar adverse effects occur at lower elevations is uncertain, although numerous lowlanders travel to moderate altitude for professional or recreational activities. We evaluated the hypothesis that nocturnal breathing, sleep, and cognitive performance of lowlanders are impaired at moderate altitude. DESIGN: Randomized crossover trial. SETTING: University hospital at 490 m, Swiss mountain villages at 1,630 m and 2,590 m. PARTICIPANTS: Fifty-one healthy men, median (quartiles) age 24 y (20-28 y), living below 800 m. INTERVENTIONS: Studies at Zurich (490 m) and during 4 consecutive days at 1,630 m and 2,590 m, respectively, 2 days each. The order of altitude exposure was randomized. Polysomnography, psychomotor vigilance tests (PVT), the number back test, several other tests of cognitive performance, and questionnaires were evaluated. MEASUREMENTS AND RESULTS: The median (quartiles) apnea-hypopnea index at 490 m was 4.6/h (2.3; 7.9), values at 1,630 and 2,590 m, day 1 and 2, respectively, were 7.0/h (4.1; 12.6), 5.4/h (3.5; 10.5), 13.1/h (6.7; 32.1), and 8.0/h (4.4; 23.1); corresponding values of mean nocturnal oxygen saturation were 96% (95; 96), 94% (93; 95), 94% (93; 95), 90% (89; 91), 91% (90; 92), P < 0.05 versus 490 m, all instances. Slow wave sleep on the first night at 2,590 m was 21% (18; 25) versus 24% (20; 27) at 490 m (P < 0.05). Psychomotor vigilance and various other measures of cognitive performance did not change significantly. CONCLUSIONS: Healthy men acutely exposed during 4 days to hypoxemia at 1,630 m and 2,590 m reveal a considerable amount of periodic breathing and sleep disturbances. However, no significant effects on psychomotor reaction speed or cognitive performance were observed. CLINICAL TRIALS REGISTRATION: Clinicaltrials.gov: NCT01130948.
