Temperature checks may not catch COVID-19, but experts say they play an important role

A new study suggests temperature checks may not be effective in catching COVID-19. Here, a Naval Academy plebe has their temperature taken before entering Alumni Hall on Induction Day in June. (Photo by Patrick Smith/Getty Images)
A new study suggests temperature checks may not be effective in catching COVID-19. Here, a Naval Academy plebe has his temperature taken before Induction Day in June. (Photo by Patrick Smith/Getty Images)

Fever and symptom screenings for the coronavirus are common at many public locations. But a new study has joined a growing body of evidence that these screenings may not actually help detect cases of the virus.

The study, which was published in the New England Journal of Medicine, followed 1,848 Marine recruits who were asked to isolate at home for two weeks and then placed into a supervised quarantine at the Citadel for more than two weeks. While there, the recruits had one roommate, wore masks unless they were sleeping, stayed at least 6 feet apart, and did most of their training outdoors.

They also were subjected to daily fever and symptom screenings.

The recruits were tested when they arrived on the closed campus and again seven and 14 days later. Overall, 16 recruits tested positive for the virus when they arrived on campus, but only one had symptoms. But 35 more recruits tested positive during the 14-day military quarantine. Only four of those had symptoms.

“Most recruits who tested positive were asymptomatic, and no infections were detected through daily symptom monitoring,” the researchers wrote. The study is just one of several that suggest regular temperature checks and symptom screenings don’t do much to pick up cases of the coronavirus.

In September, the Centers for Disease Control and Prevention said the U.S. government would remove health screenings for passengers arriving in the country. “We now have a better understanding of COVID-19 transmission that indicates symptom-based screening has limited effectiveness because people with COVID-19 may have no symptoms or fever at the time of screening, or only mild symptoms,” the CDC said in a statement.

Instead, the CDC said, it will be “shifting” strategy and “prioritizing other public health measures to reduce the risk of travel-related disease transmission.”

Another new study, also published in the New England Journal of Medicine, details how, among a crew of 4,779 on the aircraft carrier USS Theodore Roosevelt, 1,271 tested positive for the coronavirus. Of those who were infected, 77 percent had no symptoms when they tested positive for the virus. “Nearly half of those who tested positive for the virus never had symptoms,” the researchers concluded.

This raises a lot of questions about fever and symptom screenings, and whether they’re even worthwhile.

Doctors have mixed thoughts on the importance—and effectiveness—of these screenings.

Dr. Richard Watkins, an infectious disease physician in Akron, Ohio, and professor of medicine at the Northeast Ohio Medical University, tells Yahoo Life that he’s “not surprised” by the recent findings. “They are an attempt to control something that we have little actual control over,” he says. “It gives people a false reassurance that they are being proactive, but it doesn’t really distinguish the vast majority of infected people.”

Dr. John Sellick, an infectious disease expert and professor of medicine at the University at Buffalo, tells Yahoo Life that this is discussed “a lot” in hospital systems. “Part of the screenings is legally driven — in New York, we have no choice but to do this,” he says. “But there are hospitals around the country who don’t do temperature screenings for exactly these reasons.”

But Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Yahoo Life that screenings actually play two roles. “One is to find people with elevated temperatures and symptoms who have COVID-19. There, it’s probably not very efficient,” he says. But Schaffner says that the second reason is “underappreciated.”

“These screenings immediately demonstrate that, when you walk in the door, we are serious about COVID-19 and trying to control the virus,” he says. “It gives you an opportunity to see if everyone is wearing a mask and wearing it appropriately. If they don’t have a mask, we give them one and make sure they’re wearing it properly. We think it’s worthwhile to do this, if only for the educational reason.”

Screenings may play another role in helping to reduce the risk of the virus’s spread, Sellick says. “People who know they’re going to get screened may stay home if they think they’re sick or have a fever,” he says. “In that case, the screening did exactly what it was supposed to do, which is to keep people who are sick at home.”

While some people have called regular screenings “useless,” Dr. Jill Weatherhead, an assistant professor of tropical medicine and infectious diseases at Baylor College of Medicine, tells Yahoo Life that’s not correct, noting that they still can pick up some cases of the virus. “Daily screenings should still be used in the community when there is ongoing community transmission,” she says. “While a negative symptom screen does not mean the person is negative for COVID, daily screenings aim to identify potential cases using a rapid, low-cost method.”

Dr. Shobha Swaminathan, associate professor at the Rutgers New Jersey Medical School and the medical director of the infectious diseases practice at University Hospital in Newark, N.J., tells Yahoo Life that these screenings are “limited” but “still likely have a role in that they do help find patients early in the course of illness and also serve as a constant reminder to us all to be reflective of our own symptoms and be aware of minor changes in the way we feel.”

Even though they’re not perfect, there is still a role for these screenings, Dr. Amesh A. Adalja, senior scholar at the Johns Hopkins Center for Health Security, tells Yahoo Life. “Many cases are going to be asymptomatic and not going to have a fever, but some will,” he says. “You still have to have other mitigation measures. Screenings shouldn’t give people a false sense of security.”

Sellick says the latest data only underscores the importance of practicing social distancing and regularly wearing masks. “We can’t pick up everyone with screening,” he says. “But masks can help provide protection.”

For the latest coronavirus news and updates, follow along at According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.