CDC: Indoor sports like ice hockey are high risk for coronavirus

Indoor sports like ice hockey are high-risk activities for the spread of COVID-19, according to the US Centers for Disease Control and Prevention.

The conclusions about such sports were contained in a section of the CDC’s Morbidity and Mortality Weekly Report posted online Thursday.

Researchers based their findings on a review of a June 16 ice hockey game played at a rink in Tampa Bay, Fla. Players ranged in age from 19 to 53, the report said.

Within five days of the game, 15 attendees experienced signs and symptoms of the virus, and 13 ultimately tested positive, according to the report.

“Ice hockey involves vigorous physical exertion accompanied by deep, heavy respiration, and during the game, players frequently move from the ice surface to the bench while still breathing heavily,” the report said. “In this game, hockey-specific face protection varied and included metal cages or plastic half-shields (covering the eyes and the upper part of the nose); some players do not wear face protection.”

Cloth face masks, the report continued, weren’t used in the locker rooms or during the game.

“A standard ice rink in the United States measures 200 feet (61 meters) by 85 feet (26 meters),” the report said. “Boards and plexiglass, extending upward to approximately 10 feet (3 meters), surround the ice surface creating a physically segregated playing area. In addition to the 60-minute game time on the ice, during which players frequently came within 6 feet of one another, each team used a separate locker room, typically for 20 minutes before and after the game. Players from the teams did not have other common exposures in the week before the game.”

Researchers noted that the “median incubation period” for the virus is four to five days from exposure to symptom onset and ranges from two to 14 days.

“Although more than one player might have been infectious during the game, it is hypothesized that the index patient was the source of SARS-CoV-2 transmission for the other players while he was presymptomatic,” the report said.

An ice-rink, researchers asserted, poses particular pitfalls in the COVID era.

“The ice rink provides a venue that is likely well suited to COVID-19 transmission as an indoor environment where deep breathing occurs, and persons are in close proximity to one another,” the report said. " ... The higher proportion of infected players on the index patient’s team might result from additional exposures to the index patient in the locker room and on the player bench, where players sit close to one another."

Such games, the report continued, can even become so-called super-spreader events.

“The indoor space and close contact between players during a hockey game increase infection risk for players and create potential for a superspreader event, especially with ongoing community COVID-19 transmission,” the report said. “Superspreader events, in which one infectious person infects many others, can lead to explosive growth at the beginning of an outbreak and facilitate sustained transmission later in an outbreak.”

Hockey’s also had problems in New England during the pandemic.

Authorities in early September said more than a dozen cases of COVID-19 had been traced back to an ice hockey camp in New Hampshire. The nine players and four adults were associated with a summer camp that was held at Conway Arena in Nashua.

And Maine authorities said last week that a hockey referee who tested positive for COVID-19 may have exposed of hundreds of people at games he officiated the weekend before in Maine and New Hampshire.

And in August, a teenage boy from Massachusetts who crossed state lines to play in an ice hockey tournament tested positive for COVID-19.

The teenager, who was born in 2006, competed with a New York team in an elite tournament in Connecticut from July 31 to Aug. 2, according to Chet Murch, general manager of The Rinks at Exeter in New Hampshire. At least 12 other players from New York have tested positive for the virus, the Globe reported at the time.

Material from prior Globe stories was used in this report.