NEW HAVEN, Conn. (WTNH) – Results from a new study by researchers at Yale University show that testing for the presence of a single immune system molecule can detect threatening and stealthy viruses, not identified in standard tests.

“Finding a dangerous new virus is like searching for a needle in a haystack,” said Dr. Ellen Foxman, associate professor of laboratory medicine and immunobiology and senior author of the study. “We found a way to significantly reduce the size of the haystack.”

As the 2020 pandemic showed, dangerous new viruses can emerge and spread in the population well before the health system is able to detect them.

Health officials typically determine early warning signs for emerging diseases by studying animals that may transmit their infections to people. It can be challenging for health officials to determine which of the hundreds, or thousands of new viral variants represent a true danger to the public.

Health officials also often search for outbreaks of unexplained respiratory ailments, which was how SARS-Cov-2 the virus that causes COVID-19, was discovered.

By the time an outbreak of a new virus occurs, it can be too late to contain its spread, which is why researchers are looking into early detection.

In this new study, Dr. Foxman revisited a prior observation her team made in 2017, involving nasal swab testing which was thought to provide a new way to monitor for unexpected pathogens.

Nasal swabs are commonly taken to determine if a patient has a suspected respiratory infection and are then tested to detect the specific signatures of 10 to 15 known viruses, and the majority of tests come back negative, researchers said.

In 2017, Foxman’s team noted that a few cases of swabs that tested negative for the “usual suspect viruses” were still exhibiting signs that anti-viral defenses had been activated, indicating that a virus was present.

According to the study, the sign was a high level of a single antiviral protein made by the cells that line the nasal passages, researchers said.

Through that finding, researchers applied genetic sequencing methods to old samples containing the protein and found an unexpected influenza virus “Influenza C,” in one sample.

Researchers then used that same strategy and retested old samples to search for missed cases of COVID-19, during the first two weeks of March 2020. Testing was not readily available until weeks after the virus surfaced in New York.

Hundreds of nasal swab samples were collected from patients at Yale-New Haven Hospital during that time, and the swabs showed people tested negative for standard signature viruses.

Researchers said when the swabs were texted for the immune system biomarker, the majority of samples showed no trace of activity of the antiviral defense system, but a few did. Among the swabs, the team found four cases of COVID-19 that had gone undiagnosed at the time.

Findings from the study revealed that testing for an antiviral protein made by the body, even if the tests for respiratory viruses are negative, can help to pinpoint which nasal swabs are more likely to contain unexpected viruses.

Screening for the biomarker would allow researchers to narrow down the search for unexpected pathogens, which would make it feasible to do surveillance for unexpected viruses using swabs collected during routine patient care.

Samples that are found to possess the biomarker can be analyzed using comprehensive genetic testing methods to identify emerging or unexpected pathogens circulating within the patient population.

The biomarker screening would allow the healthcare community to get a jumpstart on discovering how to treat new potentially threatening viruses.

The paper was written by co-authors Cheemarla and Jason Bishai as well as former Yale researchers Amelia Hanron and Joseph R. Fauver.