Infectious disease board recommends hospitals stop screening asymptomatic patients for Covid-19

An influential board of infectious disease physicians recommended Wednesday that hospitals and other health care facilities stop routinely screening asymptomatic patients for Covid-19, saying the potential risks of screenings now outweigh the benefits.

The new guidelines from the Society for Healthcare Epidemiology of America’s board of directors may prove controversial. Throughout the pandemic, many health care facilities have routinely tested all admits in order to prevent the virus from spreading to both health care workers and other patients. They’ve also tested patients before surgery, in part out of fears that a Covid infection could lead to complications.

But the board said that, three years into the pandemic, there was still little data to suggest the routine screening prevents transmission, and substantial data to suggest it comes at a cost. A detailed commentary released Wednesday pointed to data from studies that found routine asymptomatic testing lengthened emergency department stays by nearly two hours in one hospital and seven hours in another.

Those delays can prevent patients from getting screened and sent to specialized care. And the tests can often pick up residual virus RNA in patients who were infected weeks ago.

Routine testing had seemed like a powerful additional layer of protection, but in the context of “all the kinds of unintended consequences, we may not be gaining as much as we think,” said Thomas Talbot, chief hospital epidemiologist at Vanderbilt University Medical Center and lead author of the report. “Widespread routine testing really has not been shown to be beneficial.”

The report also notes one study that found a Covid test can cost $54.50 per patient — which adds up, if you test every patient. And it cited a study in Spain that found a more targeted approach that screened just 25% of patients before elective surgery admissions was equally effective at reducing transmission.

At the same time, the report’s authors acknowledged some uncertainty. Despite hospitals’ widespread use of asymptomatic screening, relatively few studies have looked into its effects.

“It’s still a very data-absent area,” said Talbot.

Notably, the board didn’t advise facilities to abandon asymptomatic screening in all cases. It may still be helpful in specific settings, including when transmission rates are high or patients are particularly at risk. For example, it could make sense to screen all patients in the transplant or oncology wing of a hospital, where many patients are at high risk for severe Covid, or in behavioral facilities, where health care workers have to be in continual close contact with patients.

The board is advising centers “to think more critically about these policies,” said Shira Doron, an infectious disease physician at Tufts Medical Center who has published analyses of asymptomatic screening in the Veteran Affairs medical system, and who was not involved in the report.

“This is a heavy-hitting group of doctors really calling for policymakers and health systems to take a look at where we are in the pandemic and look at all these practices,” she added. “In some cases, maybe they were useful in the beginning of the pandemic and less so now.”

Yet parts of the board’s reasoning raised concerns from expert on coronavirus transmissions.  Jose-Luis Jimenez, a chemistry professor who studies disease transmission at University of Colorado-Boulder, said its understanding of viral spread was “very outdated.”

Although the board rightly pointed out that many hospital procedures don’t generate many infectious aerosols, “that does not matter when you have plenty of efficient aerosol-generating procedures such as talking going on,” Jimenez said in an email. He added that he couldn’t comment on the broader question of whether asymptomatic screening was worth the costs.

Linsey Marr, an expert on aerosol transmission at Virginia Tech, agreed that the board appeared to be downplaying the risk of aerosol transmission. “It’s a little maddening,” she said, adding that universal rapid testing, which better reflect whether a patient is currently contagious, could be a good alternative to the issues with PCR.

The guidelines may also raise concerns among immunocompromised people and others still at high risk for disease, many of whom live in areas where doctors and other health care workers aren’t masking, turning medical visits into a potentially dangerous endeavor.

Priya Nori, an infectious disease specialist at Montefiore Medical Center, treats patients with compromised immune systems. She said the guidelines still leave space for centers to protect their highest-risk patients, including through asymptomatic screening if community transmission is high or if patients will have to share rooms.

“A running narrative through the pandemic — and justifiably — has been, ‘What about the compromised  hosts?’” said Nori, who is a member of Society for Healthcare Epidemiology of America but was not involved in these guidelines. “But I think this still can be done widely and safely, and we can still protect the compromised hosts.”

In many parts of the U.S., including much of the South and Midwest, facilities have already dropped screening alongside other mitigation measures, said Doron.

Last week, Doron added, Tufts dropped its screening requirement prior to surgeries. She said the requirement can result in patients putting off needed care, and it hasn’t been shown to prevent complications.

The move could affect not only patient care, but also how Covid is tracked across the country. There has long been a debate over what percentage of Covid hospitalizations can actually be attributed to the virus, as opposed to patients who happen to test positive upon arrival but are there for a different reason.

In January, Massachusetts began requiring hospitals to report both the total number of people hospitalized with Covid and people hospitalized specifically because of Covid, which hospitals deduced by looking at the percentage of patients who received the steroid commonly used for patients with severe cases.

Roughly 30% of the people hospitalized with Covid received the drug, said Doron.

With that in mind, she said, dropping routine screenings “is going to have a big impact” on Covid data.