The study finds inadequate fever and symptom controls to filter out coronavirus cases

Representative image. AFP

Temperature and COVID-19 symptom controls such as those used in schools and clinics have again proved inadequate for detection coronavirus infections and prevention of outbreaks.

A study of marine recruits found that despite these measures and strict quarantines before training began, recruits spread the virus to others even though almost none of them had symptoms. None of the infections were contracted through symptom screening.

The study, published Wednesday on New England Journal of Medicine, has implications for colleges, prisons, meat-packing plants and other places that rely on this type of screening to detect infections and prevent outbreaks.

“We’ve spent a lot of time putting these measures in place, and they’re probably not worth the time we were hoping for,” said Jodie Guest, a public health researcher at Emory University in Atlanta who played no role in the research.

“Routine testing appears to be better in this age group” because younger adults often have no symptoms, he said.

The study was led by researchers from Mount Sinai’s Icahn School of Medicine in New York and the Naval Medical Research Center.

It involved 1,848 marine recruits, about 90 percent of them men, who were told to isolate themselves for two weeks at home, then in a controlled military quarantine on a closed university campus, The Citadel in Charleston, South Carolina, for another two weeks. This included having only one roommate, wearing masks, keeping at least 6 feet apart, and doing most of the outdoor workouts. They also had daily fever and symptom checks.

The recruits were tested coronavirus when they arrived for military quarantine and 7 and 14 days later. Sixteen, or about 1%, tested positive on arrival and only one had symptoms. Another 35 – an additional 2% – tested positive during the two weeks of military quarantine and only four experienced symptoms.

Only recruits who tested negative at the end of both quarantine periods were allowed to go to Parris Island for basic training.

Genetic testing revealed six separate sets of cases among the recruits.

“Much of the infection that occurs, we don’t even realize is occurring,” said a leader of the study, Navy Cmdr. Andrew Letizia, MD of the Naval Medical Research Center.

Quarantine measures and compliance with them were much stricter than what would happen on a typical college campus, said another study leader, Dr. Stuart Sealfon of Mount Sinai.

“This is a very infectious virus. You really need to use a combination of good public health measures, temperature controls, wearing masks, social distancing, hand washing … and comprehensive testing “to prevent the spread, he said.

Previously, federal officials said a screening project to check temperatures and symptoms at US airports caught fewer than 15 cases out of 675,000 travelers. It is not known how many cases have been lost, only very few have been detected.

A separate study published Wednesday in the New England magazine reports a blast last spring on the aircraft carrier USS Theodore Roosevelt. Among the crew of 4,779 people, mostly young people, 1,271 were infected; 77% showed no symptoms at the time of diagnosis and 45% never developed any.

The case shows that “young and healthy people can contribute to the spread of the infection in the community, often in silence,” wrote Dr. Nelson Michael of the Walter Reed Army Institute of Research in a commentary.