- A large British study found that seven symptoms in combination are the most predictive of whether a person has COVID-19.
- The key seven symptoms can help rapidly screen which patients are most likely to have COVID-19 and need to be tested for the virus in places where testing capability is limited.
A study based on data from more than 1.1 million people in England found that a group of seven symptoms were most predictive of a person testing positive for COVID-19. The combined presence of these symptoms can serve as a key to detecting COVID-19 infections in the community and help allocate tests for COVID-19 or other resources in areas where resources are limited.
These symptoms include:
- A loss or change in sense of smell
- A loss or change in sense of taste
- A new persistent cough
- Loss of appetite
- Muscle aches
“We’ve known before what sorts of symptoms people with COVID have more often than people with other sorts of respiratory infections,” David Dowdy, MD, PhD, associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, who was not involved in the study, tells Get Meds Info. “What we didn’t know is, if you want to try and predict whether someone has COVID or not, what the best symptoms would be to use for that information.”
The study was published online last month in PLOS Medicine.
A Way to Allocate Testing
At the time the study began in mid-2020, polymerase chain reaction (PCR) testing capacity in the United Kingdom was limited. PCR—the gold standard of COVID testing—looks for the presence genetic material from the virus to determine who is positive for it. According to the authors of the study, the U.K. was then using a set of four symptoms (change or loss of taste, change or loss of smell, fever, and new persistent cough) to determine which non-hospitalized patients were eligible for PCR testing for the virus.
“We show that using a combination of seven symptoms to determine test eligibility would maximize the case detection rate in the community under testing capacity constraints such as those faced in England between June 2020 and January 2021,” the authors of the study, led by Marc Chadeau-Hyam and Paul Elliott, wrote. “Where testing capacity is limited, it is important to use tests in the most efficient way possible.”
The researchers relied on data collected by the Real-Time Assessment of Community Transmission-1 (REACT-1) study, conducted between June and December 2020.
The REACT-1 study is a series of random surveys of viral prevalence in communities in England from June 2020 to January 2021. Each round surveyed different sets of people. Participants in the study were contacted through the National Health Service of the United Kingdom. They took swabs of their own throats and noses and answered questions about any symptoms they had had the week before being tested. As many as 160,000 useable responses and good quality swabs were obtained in each round of surveys.
From 26 Symptoms to 7
The participants were asked about 26 symptoms that could be related to COVID-19, including:
- Loss or change of sense of taste
- Loss or change of sense of smell
- New persistent cough
- Apetite loss
- Severe fatigue
- Muscle aches
- Heavy arms/legs
- Tight chest
- Horse voice
- Blocked nose
- Chest pain
- Shortness of breath
- Sore eyes
- Sore throat
- Runny nose
- Difficulty sleeping
- Abdominal pain/belly ache
After participants recorded their symptoms, the swabs were tested genetically for the presence of COVID-19 using a PCR test. Genetic proof of presence of the virus was then analyzed statistically for the 26 symptoms that were associated with positive PCR results. This analysis identified the combination of seven symptoms that was most predictive of the virus.
These seven symptoms were then used in the final round of the survey, conducted in January 2021, to see if they were predictive, and they were.
During the course of the study, the Alpha variant (also known as B.1.1.7) of SARS-CoV-2 started to circulate in England as part of the second wave of the pandemic. The same combination of symptoms were predictive of being positive for this variant of the virus, the study found.
Dowdy noted that the data were collected during the first year of the pandemic when not much was known about the infection or how its symptoms presented. Shortages in testing materials and other resources existed then that are not problems now—at least not in the U.S. or the U.K.
“This demonstrates how long it takes to get from the data collection phase to analysis to peer reviewed,” Dowdy says. “Today, this is more relevant for places where testing capacity is not as strong as it is in the U.K. and the U.S.”
Ultimately, he thinks it’s an important—but not a major—finding.
“It’s not earth-shattering research. I think it largely confirms what we expected to see,” Dowdy says. “I think it adds to our understanding of what symptoms are most predictive of people having COVID. And I think that’s an important addition to our knowledge.”
What This Means For You
English researchers have identified a combination of seven symptoms that can be used to predict which patients in a community are positive for COVID-19: a loss or change in sense of smell, a loss or change in sense of taste, fever, a new persistent cough, chills, loss of appetite, and muscle aches. Such information can be used to allocate COVID-19 testing and other resources when they are in short supply.
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