For those wondering how successful San Francisco's attempt to combat the spread of the coronavirus will be, a lesson from our past could give us a clue.

In 1918, the deadly Spanish influenza pandemic hit San Francisco. Nearly 29,010 people were infected with the virus, and it caused the death of 2,789 people in the city by the end of the year. The deadly virus killed an estimated 50 to 100 million worldwide.

While the flu was devastating for an unprepared public in San Francisco, just off the shoreline a completely different story emerged at the Naval Training Station on Yerba Buena Island. Home to over 6,000 military soldiers, officers, and family members at the time, the island was only accessible by boat and was protected from the virus by a strict quarantine. For 62 days, officials locked down Yerba Buena from the rest of the world.

Not one person was infected or killed by influenza during that period.

Spanish flu gained the attention of the U.S. Navy's medical officials as early as August 1918. Warnings sent to commanders explained a flu epidemic was possible at military bases in America. On Sept. 20, the Navy asked all military medical officials to report possible flu infections at their installations as it became clear the flu was starting to affect military soldiers. As a precautionary measure, Commandant Percival Rossiter of the San Francisco Naval Training station at Yerba Buena Island decided to quarantine the base on Sept. 22.

Rossiter joined the armed forces in 1896 and worked as a surgeon on numerous naval ships before being assigned to Yerba Buena Island in 1918. He instituted strict protocols for the quarantine on Yerba Buena. No one was allowed onto the island. All ferries that docked to deliver supplies could not come closer than 20 feet to a sailor on the pier.

Some sailors from the mainland were reassigned to the island to isolate themselves from the flu. They were placed in quarantine camps and had to have their nasal passages sprayed with a topical anti-infective solution. For several days, they had to stay at least 20 feet away from other sailors. All of the confined had to wear gauze masks as well.

Daily health inspections measured everyone's temperatures and hygiene rules were carefully enforced. Indoor gatherings were prevented as much as possible. Overcrowding was prohibited, and muslin screens were placed in barracks. Anyone suspected of illness was isolated from the community.

Yerba Buena's decision could not have been more timely. On Sept. 24, San Francisco reported the first diagnosed case of the Spanish flu when resident Edward Wagner returned from Chicago showing symptoms.

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By October, the U.S. military was increasingly dealing with the effects of influenza. Over 14,000 new cases per day were being reported in army camps around the nation. Eighty-eight thousand were infected, and over 1,877 had died. Several other bases in the Bay Area, including the Port Guard and Presidio in San Francisco, and Mare Island in Vallejo, also started seeing infections.

Meanwhile, for the general public in San Francisco, no warnings were given from health officials. Large gatherings, the perfect breeding ground for viral infections, continued. One hundred fifty thousand gathered in Golden Gate Park for an event on Oct. 6. Days later, 50,000 people listened to French tenor Lucien Muratore sing on the steps of the San Francisco Chronicle.

Despite escaping influenza, Yerba Buena officers had to worry about the mental health of the troops stuck on the island. To provide entertainment, officials organized a carnival and outdoor circus on the parade ground, comparable to a miniature Coney Island.

Twenty-six yeo-girls, female Navy cadets, dressed in costumes representing the Allied nations in World War I, danced at the opening festivities. Three bands of "bluejacket" sailors dressed up as clowns.

Acts included a snake charmer and a sword swallower. There were concessions for hot dogs, ice cream, cake, and pink lemonade. "The only cloud at the horizon at the island hovers over the fact that no one from San Francisco can be present to see the performance, and all praise over the entertainment must come from the folks who are promoting it," wrote the Examiner.

While life remained healthy on the island, in San Francisco cases of flu steadily grew. On Oct. 9, the Board of Health reported there were in total of 118 cases of Spanish influenza and all the patients were quarantined. "Nearly all of the cases are in a mild form," Dr. William Hassler, Chief of San Francisco's Board of Health, told the Examiner, "and residents of the city have nothing to fear if they will observe precautions."

Total cases in San Francisco reached 400 three days later. Hassler began to realize the containing the Spanish flu was no longer possible. A few days later, city hospitals were told only to take in cases that need immediate medical care and keep beds available for influenza patients.

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On Oct. 18, Hassler and the city government asked all theaters, movie houses, churches, and prize-fight arenas to close. All indoor meetings were prohibited. Public and private schools and amusement parks closed.

Case numbers continued to explode from there. The Chronicle reported 90 deaths on Oct. 29, bringing the total number of fatalities up to 677.

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Meanwhile, with San Francisco in the grips of a pandemic, Yerba Buena Island still did not have a single case of influenza.

"I wonder," a hygienic sailor who has been using a saltwater system to scrub down all ships told The Chronicle, "if the mayor knows what's around this island, and that there's no influenza from the eastern end that faces Oakland to the western top that nearly touches San Francisco."

Yerba Buena came to the help of their neighbors. With the medical system overwhelmed in San Francisco, 60 naval apprentices from the island risked their health traveling to the city to help nurse influenza patients at the San Francisco Hospital.

In early November, new cases of Spanish influenza started to decrease slowly. Only 552 new cases were reported on November 2, while deaths that day remained below 100. By the middle of November, there were only a handful of new cases. Life in the city began to return to normal.

With the threat receding, Yerba Buena Island's quarantine officially ended on Nov. 23.

Sailors were happy to be able to visit San Francisco finally. An informal parade in celebration of their liberation from the quarantine led up Market Street. Four thousand sailors got their first taste of shore leave since Sept. 22.

"As the ferry-boat made fast in the slip, the whistling, shouting, singing lads, in a charge as mighty as any that might have been made in a battle, except that all were smiling, shot through the gates, out of the Ferry Building, and inundated Market street, with wave upon wave of bobbing white hats. Mothers and sweethearts by the score were to be seen with arms around their sailor men," The Chronicle wrote.

Although new flu numbers did tick up again in Dec. 1918 and Jan. 1919, the numbers never reached those from October. After the quarantine was lifted, the Spanish flu finally did hit Yerba Buena, but the total cases were only 28 infected people, with three deaths from influenza and two from pneumonia.

The actions of the officials at Yerba Buena Island were commended by Navy Surgeon General W.C. Braisted. In a message to the Navy Bureau of Navigation, he wrote the commandant and officers at the Yerba Buena Training Station should be lauded for "demonstrating that it is possible to keep influenza out of a station under favorable at least during the height of an epidemic or as long as it is practicable to maintain the rigid quarantine."

As for Commander Rossiter, he would continue to rise the ranks to become a Navy Rear Admiral. He was eventually appointed the Navy's Surgeon General in 1933 until his retirement from the service in 1938.

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Online Photo Editor Douglas Zimmerman oversees SFGATE's Instagram and covers the Bay Area soccer scene on SFGATE's Beautiful Blog. View his latest stories and send him news tips at dzimmerman@sfgate.com. Follow on Twitter @zimpix

