For the first time in 1,099 days, Boston is getting a Patriots’ Day Marathon. But in light of the 2013 bombing, the pandemic and the recent mass shooting in the New York City subway, eyes are turning to what organizers are doing to keep everyone safe.

Public safety officials said there are no credible, specific threats against this year's Boston Marathon. Still, officials at a press conference on Thursday urged spectators to keep an eye out for suspicious activity.

"If you see something, say something. Call 911. Share the suspicious information with the police," said Jeanne Benincasa Thorpe, the undersecretary of Homeland Security for the commonwealth's executive office of public safety and security. "As all of us go out to cheer for our runners, your attention to that shared responsibility of safety will contribute to what we expect to be another successful, happy and healthy Boston Marathon on Monday."

What are the COVID-19 precautions?

All participants, volunteers, staff and vendors must be vaccinated against COVID-19, or provide a medical exemption. Testing for the virus will be available at the Hynes Convention Center on the day of the race.

Medical teams will be available to aid participants or spectators who need medical attention. Tents and medical services will be available at the starting point, at 26 stops along the race and near the finish line by Copley Square Park.

Are there any restrictions on what I can bring to the marathon?

Boston Athletic Association security will conduct bag checks at all checkpoints. Law enforcement discourages spectators from bringing large bags, such as backpacks and suitcases, strollers or weapons. A full list of prohibited items can be found here.

Can I leave my mask at home?

No. While there are no outdoor mandates, masks will still be required in medical tents and, likely, in transit: on the T, buses, commuter rail and in ride-shares like Uber and Lyft.

How will MBTA service be affected for the marathon?

Several Green Line stops will be temporarily closed Monday. Copley Square station, near the finish line, will be closed all day. South Street, Kent Street and Saint Mary Street stations will be closed between 10 a.m. and 6 p.m.