Online COVID-19 Symptom Checkers May Not Catch Severe Illnesses

Digital COVID-19 symptom checkers in the U.S. and the U.K. may fail to identify severe COVID-19 and other serious illnesses such as bacterial pneumonia or sepsis, according to a group of public-health researchers.

The online tools often advise patients to stay home and may prevent them from getting prompt treatment, the team writes in BMJ Health and Care Informatics.

"As a frontline COVID doctor myself, I was concerned that the symptom checker was delaying the presentation of patients with severe COVID-19 to the hospital, and this was adding to the pressure on higher-dependency areas, such as" intensive-care units (ICUs), said senior author Dr. Daniel Goyal of the Gibraltar Health Authority and Gibraltar's COVID-19 Research Group.

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"The earlier we can identify pneumonia, the easier it is to facilitate recovery," he told Reuters Health by email. "If patients present late, then they have higher mortality, higher rates of ICU admissions, longer admission, and they take much longer to recover, if they survive."

Dr. Goyal and his colleagues ran a simulation study in April 2020 on nationwide symptom checkers in the U.S., UK, Japan and Singapore. They used 52 cases that represented typical COVID-19 presentations, including mild, moderate, severe and critical cases, as well as COVID-19 "mimickers" such as bacterial pneumonia and sepsis.

The case scenarios included symptoms such as cough, fever and shortness of breath, along with underlying conditions, immunosuppression, age, symptom severity and symptom duration. They compared the recommendations, including whether patients were advised to seek medical care or stay at home.

Overall, the research team found that the Japan and Singapore checkers were twice as likely to recommend medical care. About 88% of the Singapore cases were triaged onward, followed by 77% in Japan, 44% in the U.K. and 38% in the U.S.

Both the U.K. and U.S. tools consistently failed to identify severe COVID-19, bacterial pneumonia and sepsis, often advising patients to stay at home and not seek care.

The Singapore and Japan symptom checkers recommended clinical assessment after four days of symptoms, whereas the U.S. and the UK tools didn't change based on the duration of symptoms.

Age also didn't appear to affect the recommendations in the U.S. or U.K., but all patients in Singapore over age 65 with viral symptoms and all "older adults" in Japan who had viral symptoms for more than two days were advised to seek medical care.

The research team specifically looked at shortness of breath and found that both the Singapore and Japan tools advised immediate clinical care for all patients who had breathing issues. The U.S. and UK systems gauged severity and advised patients with "mild" shortness of breath to stay at home.

The Singapore and Japan checkers also emphasized seeking care if any symptoms grew worse, whereas the U.K. and U.S. tools focused on the "stay at home" message.

"I think we have fallen so far away from our usual standards of care during this pandemic," Dr. Goyal said. "If you had said one year ago that we would not clinically assess a patient with respiratory symptoms who complained of shortness of breath, I simply would not have believed you."

The symptom checkers have improved, Dr. Goyal said, with some incorporating pulse oximetry measures and other COVID-related factors. The research team plans to repeat the analysis again in April.

"As the pandemic changes, we need to be constantly adapting the tools we've built to fight COVID," said Dr. Timothy Judson of the University of California, San Francisco. Dr. Judson, who wasn't involved in the study, helped to develop the university's symptom checker early in the pandemic.

By the late spring, they changed the algorithms to recommend tests for anyone with COVID-19 symptoms, Dr. Judson said. Now that COVID-specific treatments are available, the algorithms shifted again to identify eligible patients. Dr. Judson recommended using local COVID-19 checkers when possible.

"The advantage of these tools is that for many of them, not only do you get advice, you also get connected to care," he told Reuters Health by email. "You can schedule your test or appointment in seconds. These integrated tools also help your doctor to keep track of your symptoms."

—Carolyn Crist

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