What is it about?
During COVID-19, health authorities recommended that high-risk patients monitor their oxygen levels at home using pulse oximeters to catch dangerous drops before symptoms appeared. However, this strategy had not been tested in lower-resource settings. We conducted a randomized trial with over 1,800 high-risk COVID-19 patients in Honduras, comparing those who received pulse oximeters with daily phone monitoring to those with phone monitoring alone. While patients with pulse oximeters were more likely to be referred for medical evaluation, we found no difference in hospitalizations, intensive care admissions, or deaths between the groups. The low incidence of severe outcomes—likely due to high vaccination rates and circulating variants causing less severe disease—meant we couldn't definitively determine whether home oxygen monitoring reduces the likelihood of severe COVID-19 in this context.
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Why is it important?
This is the first randomized trial to test whether home pulse oximeters reduce COVID-19 deaths in a lower- and middle-income country. The World Health Organization recommended this approach based largely on evidence from high-income countries, but implementing it in resource-limited settings requires purchasing thousands of devices and training staff—investments that must compete with other urgent health priorities. Our study is unique because it took place when most participants were highly vaccinated and Omicron (a less severe variant) was circulating, reflecting the current reality rather than earlier pandemic conditions. We found that pulse oximeters successfully detected low oxygen levels in over one-third of patients, including many who had "silent hypoxia"—dangerous oxygen drops without breathing difficulties. This led to more patients being referred for medical evaluation (7% versus 4%). However, we found no difference in hospitalization rates between groups, and with only one death occurring during the entire study, we could not determine whether pulse oximeters reduce mortality. These findings suggest that in highly vaccinated populations with phone-based monitoring, pulse oximeters increase detection and referrals but may not prevent severe outcomes when baseline risk is already low. This evidence helps ministries of health in similar settings make informed decisions about where to invest limited resources. More broadly, it demonstrates the importance of testing global health recommendations in the specific contexts where they will be used, particularly as we prepare for future disease outbreaks.
Perspectives
This study taught me that the most important question isn't always "did it work?" but rather "what did we learn, and how does it help us prepare for next time?" When we designed this trial in 2020, COVID-19 was devastating Honduras. By the time we enrolled participants in 2022, vaccination rates were remarkably high and the circulating variant was less severe—wonderful for public health, but it meant we couldn't answer our original question about preventing deaths. However, we learned something equally valuable: that people in resource-limited settings can and will successfully use health technology when it's introduced thoughtfully, and that the human connection of daily phone calls mattered as much as the technology itself. Two companion papers examine how this intervention was actually implemented—one focusing on whether we delivered it as intended (fidelity), and another on how patients and healthcare workers felt about it (acceptability and appropriateness). Integrating these implementation science perspectives into a traditional clinical trial revealed insights we would have missed otherwise: that participants loved the program while some healthcare workers had doubts, that mental health support during isolation was an unexpected benefit, and that our design inadvertently excluded the most vulnerable people who never made it to testing centers. These findings point toward future research questions about equity, optimal implementation strategies, and when remote monitoring makes sense to deploy. What strikes me most is the gap between who we reached and who we didn't. We successfully implemented this program among people who could access testing centers, had phones, and were well-vaccinated. But what about those who couldn't? As we prepare for future outbreaks—whether COVID-19 or other diseases—we need to design interventions that reach everyone, not just those already connected to healthcare systems. That's the work still ahead.
Kathryn Roberts
University of California, Berkeley
Read the Original
This page is a summary of: Impact of self-administered pulse oximetry among non-hospitalized patients at risk of severe COVID-19 in Honduras: A pragmatic, cluster-randomized trial with temporal clustering, PLOS Global Public Health, November 2025, PLOS,
DOI: 10.1371/journal.pgph.0004618.
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