BOSTON (WHDH) - The number of presumptive coronavirus cases in Massachusetts has more than doubled to 27, according to state officials, with all 15 new cases connected to a Biogen employee conference in late February — and several schools have been affected by the new cases as well.

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Officials said there are 27 presumptive positive coronavirus cases across the state, along with one confirmed case. Including the latest numbers, 23 of the presumptive cases are associated with the Biogen conference at the Marriott Long Wharf in Boston.

The presumptive positive cases include five from Middlesex County, ranging in age from 40s to 60s; four cases from Norfolk County ranging in age from 40s to 60s; and a female whose age and county of residence are unknown at the time of this release.

Boston Public Health Commission officials said the other five cases were Boston residents — a woman in her 30s, a woman in her 60s, a man in his 40s, a man in his 50s and a man in his 60s.

All patients who tested presumptive positive are isolating at home, state officials said.

Some of the patients have children at various schools in the metro Boston area, including at Horace Mann Elementary School in Newton, Bowman Elementary in Lexington and Natick High School. Custodians gave those schools additional cleaning Sunday, school officials said.

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The risk of COVID-19 to the general public in Massachusetts remains low at this time.

The State Public Health Lab’s result is considered “presumptive positive” and the specimens will now be sent to the US Centers for Disease Control and Prevention (CDC) for confirmation.

The Department of Public Health is providing daily updates on the number of confirmed and presumptive positive cases. Case-specific information will be updated on the site Monday, March 9.

As of March 4, 719 people have been subject to self-quarantine in Massachusetts because of COVID-19. Of those, 470 people have completed monitoring and are no longer quarantined, while 249 are currently quarantined. This information is updated online each Wednesday.

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Symptoms of coronavirus include fever, cough, and shortness of breath, according to the CDC. Reported worldwide illnesses have ranged from mild symptoms to severe illness and death.

The virus is thought to spread mainly from person-to-person, typically between people who are in close contact with one another and via respiratory droplets produced when an infected person coughs or sneezes.

Click here for more information on the coronavirus and tips on how to protect yourself.

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