Fever checks have broadly become the first level of coronavirus detection as businesses, stores and schools try to reopen, but a new study warns that relying on them as a single screening tool could lead to a false sense of security.
Fever is generally the first symptom of a coronavirus infection, according to a study by the University of Southern California, followed by cough, nausea, vomiting and lower gastrointestinal symptoms, such as diarrhea.
For the study, researchers used data from the World Health Organization, which collected information on nearly 60,000 confirmed cases of COVID-19, to model the sequence of symptoms. Limitations of the study, published last week in a journal for public health, include that the cases were almost all from China in the early days of the pandemic, before other types of symptoms were recognized.
While a temperature check can detect people who are showing symptoms, there are a significant number of people who can not develop a fever, said co-author Peter Kuhn, a professor of biological sciences, medicine and engineering at USC.
A temperature of 100.4 F is considered short by the Centers for Disease Control and Prevention.
With more than 21 million confirmed COVID-19 cases worldwide, public health officials have learned that the infection can cause a wide range of symptoms, from barely noticeable sniffles and headaches to problems with breathing and chest pain. The CDC currently lists the following possible symptoms, but says there may be others:
- Fever or fever
- Cough
- Shortness of breath or difficulty breathing
- Wurgens
- Muscle as body
- Headache
- New loss of taste or smell
- Sore throat
- Congestion as a runny nose
- Nausea as vomit
- Diarrhea
Studies have shown that children are more likely to have milder symptoms, which can be mistaken for another disease. A new loss of smell and taste is a fairly early symptom for milder cases, and is more common among younger patients and women.
Symptoms can appear at any time between two to 14 days, although about five to six days after exposure is the average. Although many people never show signs of infection, even those that eventually become symptomatic could spread the disease for days before developing a fever, said David Paltiel, a professor at the Yale School of Public Health.
“If you use signs and symptoms as a basis to move forward, it’s like the fire department waits until a house is on fire before it takes action,” said Paltiel, who published a study in July on bringing students in. students return to campus at JAMA Network Open.
At UPMC Magee-Womens Hospital in Pittsburgh, all visitors are screened with temperature scanners, said Dr. Joe Suyama, head of emergency services.
“They are not the technological safety net that most people expect them to be,” he said. “However, most institutions, hospitals and schools implement some form of screening.”
Suyama and others hope that, along with blocking entry for people with symptoms, the screening stations will remind people that no one can leave their guard. Fever checks should be part of other protocols that cover masks and social distance, say infectious disease experts.
“Because screening for the virus is so incomplete, it’s better not to count on it,” said Dr. David Thomas, a professor of medicine and director of the Division of Infectious Diseases at Johns Hopkins Medicine. “It’s not that we do not believe in testing and screening, but we do not trust them at all.”
