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On March 2, San Francisco Mayor London Breed and New York City Mayor Bill de Blasio shared tweets on the novel coronavirus (see them in the gallery above). The tone and content of the messages show how radically different their approaches were in the early stages of the outbreak.

This was just one day after New York City identified its first COVID-19 patient and three days before San Francisco reported its first cases.

The messages, surfaced by Vox reporter German Lopez, show the discrepancy in the mayors' attitudes at the start of the pandemic. Breed sent out a string of tweets advising residents to prepare for "disruption." De Blasio posted some public health messages, but he also shared a tweet that evening telling New Yorkers to go out on the town. As you can imagine, his encouragement to have fun was more widely shared than any of his other messages or any of Breed's stern warnings.

In the Tweet, de Blasio wrote, "Since I’m encouraging New Yorkers to go on with your lives + get out on the town despite Coronavirus, I thought I would offer some suggestions. Here’s the first: thru Thurs 3/5 go see “The Traitor” @FilmLinc. If “The Wire” was a true story + set in Italy, it would be this film." This tweet was shared 2,100 times and liked 1,700 times.

De Blasio also posted a Tweet advising New Yorkers to wash their hands and cover their coughs. It was retweeted 19 times and received 49 likes.

Meanwhile Breed advised residents to "Prepare for possible disruption from an outbreak" and then included a bulleted lists of things to do: "-Have a supply of essential medications for your family -Make a child care plan if you or a caregiver are sick -Plan for how to manage a school closure -Plan for how to care for a sick family member w/out getting sick yourself." The tweet was shared 10 times and given 21 hearts.

A second tweet by the major listed ways to reduce spread of the virus. It received four retweets and likes.

Breed also fired off several tweets updating residents on the city's preparations such as expansion of emergency workers and outreach efforts to share information with different segments of the population.

These tweets, from New York's mayor and San Francisco's mayor, were posted on the same day. pic.twitter.com/jvdiLrknD8 — German Lopez (@germanrlopez) April 6, 2020

San Francisco, the entire Bay Area and California in general has been lauded for its early action in addressing coronavirus while active response came later in New York. Some experts believe S.F.'s earlier moves may be one reason the city has experienced dramatically fewer cases and deaths than New York. In mid-March, both New York City and San Francisco had a couple dozen cases. As of Thursday morning, New York City had reported 4,571 deaths; San Francisco meanwhile had 10 and the nine-county Bay Area, 115. Cases in New York state number 78,221 versus 19,127 in California, according to Johns Hopkins University.

Breed declared a state of emergency in San Francisco on Feb. 25, while New York's declaration came on March 13. Bay Area counties began issuing shelter-in-place orders on March 16, and California Gov. Gavin Newsom implemented a mandate for the entire state on March 19. New York's order came about a week later.

While early action may be one reason for San Francisco's lower numbers, health experts believe several other factors may also be at play, including urban density (New York is more dense than California), differences in mass transit (New Yorkers are more likely to be packed on subways than Californians) and access to testing (New York has tested more of its residents than California).

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Amy Graff is a digital editor with SFGATE. Email her: agraff@sfgate.com.