An usher at two Broadway theaters in Manhattan has tested positive for coronavirus, deepening growing concerns over the virus' impact.

“Last evening, we were notified that a part-time employee of both organizations has tested positively for COVID-19 (coronavirus)," said a joint statement from the Shubert and Nederlander Organizations. "Immediately upon learning of the positive test, both organizations began taking every step necessary to ensure the safety of our audiences, performers, crew, and building staff."

The individual most recently worked as an usher at the Shubert's Booth Theater, home to "Who's Afraid of Virginia Woolf," starring Laurie Metcalf and Eddie Izzard, on March 3 through Friday, March 7.

The employee also recently worked at the Brooks Atkinson Theater, home to the musical "Six," on Feb. 25 and a matinee on March 1, expediting lines outside the theater. The opening night for "Six" is set for March 12.

A deep cleaning, which the theater says follows all current government standards, has been completed at the Booth Theater, and "out of an abundance of caution," a deep cleaning is scheduled at the Brooks Atkinson overnight.

Tonight's performances of both shows, as well as all other Broadway performances, will continue as scheduled.

However, ticketholders who prefer to attend a future performance can exchange their tickets at the point of purchase, the theater owners said.

The statement continues:

“Leadership of both organizations have been in contact with the State of New York, as well as the City of New York, and we are closely following all protocols related to containment and prevention. We are exercising necessary due caution with all our employees and the public. Employees of the theaters and productions who may have been exposed were notified and advised to monitor their health diligently and follow best practices related to personal hygiene, as well as directed to stay at home if they are ill. In addition, we are urging any high-risk audience members who attended these performances in the past several days to follow similar guidance."

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The statement says the teams continue to monitor the situation and address concerns, as well as a pledge to keep theatergoers informed.

"Among the many reasons that Broadway is unique is the connection between our audiences, the performers, and the women and men who work on the production teams and within our theaters. We are committed to making sure this never changes, and we will continue to provide a safe and special experience for all involved,” the statement concludes.

In recent days, many shows have curtailed stage-dooring – where fans wait outside the stage door after performances to get stars' autographs – and some are offering deep discounts to lure jittery audience members. Theaters also have increased cleaning scheduled and added hand sanitizer in the lobby of every theater.

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The Broadway League issued a statement reading:

"The Broadway League is closely monitoring the evolving coronavirus situation on behalf of the Broadway community. The safety and security of our theatergoers and employees is our highest priority. We are following the lead of our city, state and federal elected officials as we implement strategies recommended by public health authorities and the Center for Disease Control (CDC) in all of our theaters and offices as all productions continue to play as scheduled.

"We have significantly increased the frequency of cleaning and disinfecting in all public and backstage areas beyond the standard daily schedule, and we have added alcohol-based sanitizer dispensers for public use in the lobby of every theater. We invite patrons to make use of soap, paper towels, and tissues available in all restrooms. As an added precaution, we are highly recommending that all stage door activities be eliminated for the time being. We remain vigilant, and we are prepared to make decisions based on current recommendations, as well as in response to changing conditions."

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The Broadway League statement also encourages anyone who experiences symptoms of cold or flu to stay home.

On Tuesday, producer Scott Rudin announced that all remaining tickets to "To Kill a Mockingbird," "West Side Story," "The Lehman Trilogy," "Who’s Afraid of Virginia Woolf?" and "The Book of Mormon" from March 12 to March 29 will be offered for $50 starting at noon on Thursday.

“As long as New York City is open for business, its beating heart remains the Broadway stage. This is an unprecedented opportunity for everyone to see a show that they otherwise might not have had easy and affordable access to. I can’t pretend that great theater is the panacea we’ve been waiting for, but in the meantime I think we could all use a few hours away from the evening news,” Rudin said in a statement.

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Producers are notoriously unwilling to cancel shows, which had an average paid admission last week of over $100. The last time they did so was in 2016, when a ban on travel in New York and the suspension of public transportation due to snow forced theater owners to cancel one day’s shows. Superstorm Sandy in 2012 also darkened Broadway for four days and cost more than $8.5 million in lost revenue.

Broadway is particularly vulnerable to the coronavirus because its audience skews older, thousands of people are packed into small seats for every show and the industry is dependent on tourism. Of the 14.8 million admissions in the 2018-2019 season, 65% were made by tourists – 46% from Americans outside New York and 19% from other countries.

Last week, attendance was actually higher than the previous week but some believe Broadway cannot avoid the effects of the outbreak forever. Broadway could feel the impact if school groups and tourists decide to skip New York in big numbers, though that will likely be felt gradually since the average ticket purchase for a Broadway show is made some 47 days before the performance.

Health officials are advising those at high risk of developing severe illness from the coronavirus to avoid crowds, particularly in poorly ventilated areas, and to avoid touching common surfaces when out in public. The risk of illness and death is highest among those over age 80, and increases with age, starting at age 60, according to the federal Centers for Disease Control. Members of the public are advised to carefully consider whether to attend large public events, and to use common sense precautions of covering coughs and sneezes, frequent hand-washing and avoiding touching the face.

Contributing: Associated Press