The number of cases of coronavirus in the state hit 92 yesterday. And in a state of almost 7 million residents that’s cause to declare a state of emergency?

Some may wonder whether the alarms being sounded are going overboard. That evidently includes some South Boston business owners complaining about all the money they won’t make this Sunday because the city has cancelled the annual St. Patrick’s Day parade there.

Mayor Marty Walsh pushed back on any idea that the city is overreacting. “I hope it’s being blown out of proportion,” he told Globe columnist Adrian Walker. “I hope I can stand here in three weeks and say it was blown out of proportion, and we did all this preparation for nothing.”

But if the region avoids a massive surge in coronavirus cases, public health experts say it won’t be proof of how unnecessary the sweeping response was but rather how effective it was.

That’s the nature of dealing with a potentially fast-spreading contagion like the new virus global health authorities are contending with. If you wait for clear signs that drastic steps are needed, it will invariably be too late to head off a public health crisis.

That’s what has happened in Italy. The country has gone over the span of less than a month from having 3 cases to 10,000, with 631 deaths.

A week ago, an infectious disease physician in Lodi, in northern Italy, said the virus hit his hospital “like a tsunami.” The country’s health care infrastructure, particular in northern Italy where the greatest number of cases are clustered, is being strained to the breaking point, with life-sustaining ventilators now viewed “like gold,” according to one doctor whose Facebook post about the crisis has gone, well, viral.

What public health authorities in Massachusetts and throughout the US are trying to do is prevent that from happening here.

“The purpose of moving forward with these measures now is to act before the numbers increase to a point where the virus spread is severely impacting the Commonwealth,” Gov. Charlie Baker said yesterday in announcing the state of emergency. “The highly contagious nature of this disease means that if everyone plays their part in slowing its spread, the number of people who become infected and require medical attention doesn’t spike all at once, which would overwhelm many of our systems.”

The public health goal, in epidemiological terms, is “flattening the curve.”  As this Vox piece shows, along with trying to minimize the total number of cases, it’s critical to slow the speed at which the number of cases grows. What’s crucial is to not have the graph line plotting active cases move above a level that marks the health care system’s maximum capacity to care for critically ill patients.

That helps explain things like the closure of college campuses in the state. Students are unlikely to face serious consequences if they contract coronavirus, but they will be vectors for its spread.

“The more young and healthy people are sick at the same time, the more old people will be sick, and the more pressure there will be on the health care system,” Emily Landon, an infectious disease specialist at the University of Chicago, told Vox. “That means my mom and your mom will have a hospital bed if they need it.”

And that, Walsh can tell any Southie enterprises griping about losing a big day of business on Sunday, is no blarney.

MICHAEL JONAS

CORONAVIRUS

Gov. Charlie Baker declares a state of coronavirus emergency in Massachusetts, in part because of a handful of cases in Berkshire County whose origin can’t be traced. Also, getting tested for the virus is not that simple — a doctor just can’t order the test. (CommonWealth)

The elderly and those with chronic illnesses are particularly vulnerable to COVID-19, so nursing homes are beginning to sharply restrict access to their facilities. But interrogating visitors about their health and where they’ve been is not that easy, say some operators. (CommonWealth)

The recent Biogen conference in Boston became the vector for most cases of coronavirus in the state. (Boston Globe)

The mayor of North Adams, Thomas Bernard, goes into self-quarantine after the vice president of the city council, Jason LaForest, is tested for COVID-19. LaForest thinks he may have been infected while attending a meeting of municipal leaders in Boston. (Berkshire Eagle)

As of Wednesday, only one designated caregiver — such as a parent, spouse or legal guardian — will be allowed to visit patients at Falmouth and Cape Cod hospitals and JML Care Center in Falmouth, according to new protocols announced Tuesday by Cape Cod Healthcare President and CEO Michael Lauf. (Cape Cod Times)

Lifestyle changes. CNN cancelled its in-studio audience for the next Democratic debate. (MassLive). John King at CNN talked to WGBH about how new coronavirus mitigation concerns could impact how candidates campaign. Town meetings could be rescheduled. (Telegram & Gazette) Stop & Shop’s online orders surge. (WBUR) Passenger traffic at Logan International Airport is down 13 percent. (Boston Globe) In one New Hampshire town, the ballot machine clogged during municipal elections due to the use of hand sanitizer. (Eagle-Tribune)

Education: Smith College tells all students to move out of the dorms. (MassLive) Children who attend Natick High School tested positive. They are in self-quarantine, so the school remains open for now. (MetroWest Daily News)

Business: Here’s how Worcester-area institutions are keeping their facilities clean and sanitary. (Telegram & Gazette)

While the two leading Democratic presidential candidates cancelled rallies scheduled for last night in Cleveland because of coronavirus, President Trump said he has no intention of scrapping big gatherings to rally his base. (Boston Herald)

BEACON HILL

A study by the Beacon Hill Institute commissioned by the conservative Massachusetts Fiscal Alliance says gas prices could rise far higher under the proposed Transportation and Climate Initiative than the Baker administration has projected. (Boston Herald) William Burke of the Beacon Hill Institute and Laurie Belsito of the Fiscal Alliance Foundation explain the report’s findings (CommonWealth)

MUNICIPAL MATTERS

Critics are blasting plans for an electrical substation in East Boston. (Boston Globe)

Mayor Thomas Koch said he stands by his decision to sponsor a 2018 home rule petition that allowed the son of a disabled police officer to jump the list of civil service candidates in Quincy. (Patriot Ledger)

ELECTIONS

Joe Biden swept primaries in Michigan, Missouri, Mississippi, and Idaho, solidifying his standing in the battle for the Democratic presidential nomination as Bernie Sanders struggles for a path forward. (New York Times) The Globe’s James Pindell says the race is “effectively over.” For all the talk of Biden as a moderate, Jeff Jacoby says the former VP has moved considerably to the left. (Boston Globe)

Does an Elizabeth Warren endorsement matter in the race? This poll says no. (MassLive)

Kevin Johnson and Mac D’Allesandro explain what ranked choice voting would have meant during last week’s Massachusetts Democratic primary. (CommonWealth)

BUSINESS/ECONOMY

Raynham surgical devices company Medrobotics was fined by Attorney General Maura Healey’s office for failing to pay its employees more than $1 million in salaries since February. (The Enterprise)

ARTS/CULTURE

Requests for the state film tax credit dropped steeply in 2018. (Gloucester Daily News)

The high drama of the rise and fall of former Fall River mayor Jasiel Correia II has been given the cinematic nod from Hollywood with a docu-series on tap. The executive producer is actor Mark Wahlberg and director is award-winning Canadian filmmaker Brent Hodge. (Herald News)

TRANSPORTATION

At South Station, track information on train departures will be pulled down from the big display board in the station rotunda one minute before leaving to prevent dangerous last-minute dashes. (State House News)

ENERGY/ENVIRONMENT

A subcommittee report from the Cape Cod Commission gave good reviews to the first phase of plans to restore the Herring River in Wellfleet. (Cape Cod Times)

CASINOS

Lots of Springfield-area agencies are asking for money to “mitigate” the impact of MGM Springfield (MassLive)

CRIMINAL JUSTICE/COURTS

The MBTA reports it has had record low crime rates for the fourth year in a row. (Boston Globe)

State Police commanders get anti-bias training. (Telegram & Gazette)

A woman is jailed for protesting about jail conditions. (AP)