Across the United States cases of COVID-19 are on the rise due to the Omicron variant. According to the NFL’s chief medical officer, Dr. Allen Sills, the spread of the virus in the league is due to symptomatic players, not those who are asymptomatic.

In an interview with the NFL Network, Sills claimed the league has not witnessed any verifiable asymptomatic spread this season.

“I think all of our concern about [asymptomatic spread] has been going down based on what we’ve been seeing throughout the past several months,” Sills told ESPN in a subsequent interview. “We’ve got our hands full with symptomatic people. Can I tell you tonight that there has never been a case when someone without symptoms passed it on to someone else? No, of course I can’t say that. But what I can say to you is that I think it’s a very, very tiny fraction of the overall problem, if it exists at all.

“Clearly if you want to look at the overall pattern and concern about transmission, it is not being driven by people who have no idea that they are infected and they are infecting scores of others. This is being driven by people with symptoms and the exposures during that symptomatic period.”

This strategy departs from the belief that most public health organizations have shared throughout the pandemic, which emphasized that the asymptomatic should take precautions as well since they could spread the virus, or even not know that they are COVID-19 positive.

Sills claimed that it was because of the testing schedule that some players were spreading the virus and not attributing symptoms to COVID-19 since they had received a negative test in the days prior.

“We were seeing people walk around for two or three days and expose others because they didn’t speak up about their symptoms because they had gotten that negative test,” Sills said. “So we’re at our best when we’re testing at the onset of symptoms.”

He added the league was able to trace, using genomic sequencing, that 87 percent of positive cases in the NFL came from outside of team facilities.

“Asymptomatic transmission inside our facilities just didn’t fit with what we were seeing,” he added

Despite the surge in positive cases across the US, the NFL and the NFL Players Association finalized an agreement last week that would pause weekly testing for vaccinated players and instead implement a random sampling system across teams and positions. Unvaccinated players will still be tested daily and vaccinated players who experience symptoms are expected to report them and be tested.

Players who test positive are required to isolate for 10 days, but under these new protocols, players who are vaccinated are able to test out of quarantine as early as the day after their initial positive test based on negative tests and control threshold readings.

Over 94 percent of players and nearly 100% of coaches are vaccinated. This week 154 players tested positive for COVID-19, with over 300 testing positive over the past two weeks.