Fever screening widely used in schools, businesses. Is it reliable?

Fever checks have largely become the first level of detection for coronaviruses as businesses, stores and schools try to reopen, but new study warns relying on them as a single screening tool could lead to a false sense of security.

Fever is usually the first symptom of a coronavirus infection, according to a University of Southern California study, followed by cough, nausea, vomiting, and lower gastrointestinal symptoms, such as diarrhea.

For the study, the researchers used data from the World Health Organization, which included information on nearly 60,000 confirmed cases of COVID-19, to model the order of symptoms. The limitations of the study, published last week in a public health journal, include that almost all cases originated in China during the early days of the pandemic, before other types of symptoms were recognized.

While a temperature check can detect people who have symptoms, there are a significant number of people who could be contagious and do not develop a fever, said study co-author Peter Kuhn, professor. of Biological Sciences, Medicine and Engineering at USC. .

A temperature of 100.4 F is considered a fever by the Centers for Disease Control and Prevention.

With more than 21 million confirmed cases of COVID-19 worldwide, public health officials have learned that the infection can cause a wide range of symptoms, from barely noticeable sniffles and headaches to difficulty respiratory and chest pain. The CDC currently lists the following possible symptoms, but says there may be more:

• Fever or chills
• Cough
• Shortness of breath or difficulty in breathing
• Tired
• Muscle or body pain
• Headache
• New loss of taste or smell
• Sore throat
• Stuffy or runny nose
• Nausea or vomiting
• Diarrhea

Studies have shown that children are more likely to have milder symptoms, which could be mistaken for a different disease. New loss of smell and taste is a common early symptom in milder cases, and is more common in younger patients and women.

Symptoms can appear anytime between two and 14 days, although about five to six days after exposure is the average. Although many people never show signs of infection, even those who 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 for moving forward, it’s like firefighters are waiting for a house to burn down before taking action,” said Paltiel, who released a study in July on the return of students to campus. in JAMA Network Open.

At the UPMC Magee-Womens Hospital in Pittsburgh, all visitors are examined with temperature scanners, said Dr Joe Suyama, chief of emergency services.

“They are not the technological safety net that most people expect of them,” he said. “However, most facilities, hospitals and schools implement some form of screening.”

Suyama and others hope that in addition to blocking entry to people with symptoms, testing stations will remind people that no one can let their guard down. Fever checks must be part of other protocols that include masks and social distancing, infectious disease experts say.

“Because testing for the virus is so imperfect, it’s best not to count on it,” said Dr. David Thomas, professor of medicine and director of the infectious disease division at Johns Hopkins Medicine. “It’s not that we don’t believe in testing and screening, but we don’t completely trust them.”