Swimming pools closed. Businesses were quarantined. Hospitals transported infected patients in special ambulances. Worried citizens avoided crowds by staying away from buses and theaters.
That's how Maryland, and much of America, coped with the polio epidemics that swept through the country in the 1950s.
"Your parents would tell you, don't get overly tired and don't get too close to crowds. Then the summer would come and they'd close the pools and that would be it," said Richard Holland, 72, who grew up in Catonsville and graduated from Baltimore Polytechnic Institute in 1951.
But that began to change 50 years ago today, when scientists announced that a polio vaccine developed by a young researcher named Jonas Salk had proven safe and effective in a clinical trial.
The mass vaccinations that followed ushered in what many consider the modern era of vaccine development, convincing a skeptical public that medical research could, in fact, work wonders to eradicate diseases given sufficient funds.
"It provided a path toward prevention not only of this disease, but it opened the door for development of a number of other vaccines," said Dr. Neal Halsey, director of the Institute for Vaccine Safety at the Johns Hopkins Bloomberg School of Public Health.
The polio effort spurred research that led to vaccines for measles, mumps, rubella and influenza. It also opened a door that researchers still use in their efforts against AIDS, avian flu, malaria and other infectious diseases that are second only to cardiovascular problems as the leading cause of death worldwide.
"I think it was one of the best examples we have of how fundamental research can be interlinked with a very human application," said Rita Colwell, a University of Maryland scientist and former director of the National Science Foundation.
To test its effectiveness and prove its safety, the original Salk vaccine was put through the largest clinical trial the world had ever seen. Some 440,000 children were injected as part of a $7.5 million research effort funded by the National Foundation for Infantile Paralysis, which later became the March of Dimes.
Although vaccines against smallpox, diphtheria and tetanus had been developed years earlier, Salk was one of the first to take advantage of a new technique for growing polio viruses, using tissue cultures.
In fact, researchers John Enders, Frederick Robbins and Thomas Weller eventually won a Nobel Prize for their groundbreaking tissue culture work in the 1940s, an honor that escaped Salk and Sabin.
Enders and his team deserved the Nobel, many experts say, because their discovery made it easier to study other viruses and develop more vaccines.
Polio, of course, had been around since ancient times, and was identified as a specific disease as early as the 1840s. It was never as widespread as influenza, and most of those who contracted it survived.
But by middle of the 20th century, no disease inspired as much fear. The mysterious virus had crippled President Franklin D. Roosevelt and confined thousands, mostly children, to coffin-like respirators. Polio was every parent's nightmare.
"We had iron lungs all over the place, and you were always worried about an outbreak," said Dr. Frank M. Calia, 68, now chief medical officer at the University of Maryland Medical Center.
So it was that news of the polio vaccine, coming on the 10th anniversary of Roosevelt's death, generated a massive wave of relief and made Salk a national hero.
"It was a tremendous achievement, coming up with that vaccine," said Dr. John W. Littlefield, 79, a retired researcher and former director of the Johns Hopkins Children's Center.
On the same day as the announcement, federal officials licensed six pharmaceutical firms to make the vaccine. Within a week, the first truckloads arrived in Baltimore and state health officials began vaccinating 140,000 schoolchildren across Maryland.
"You were just told you had to take it. I don't think anybody was given a choice," said Stanley Nusenko, 59, who lined up for the shots with other fifth-grade students at Howard Park Elementary School.
Fear of polio's consequences helped Nusenko put up with a series of three injections, spread over several weeks. "If there was anything that stuck in your mind, it was those iron lungs," said Nusenko, a retired federal management analyst who lives in Westminster.
The vaccine distribution process had it bumps, but local doctors don't recall panic over shortages, or outlandishly long lines. "It was a different world then. We ordered the vaccine, we got it, we gave it out, that was it," said Dr. Henry Seidel, 82, a retired pediatrician who gave shots to children at his office in the 1400 block of Eutaw St.
Seidel, who still teaches pediatrics part-time at the Johns Hopkins School of Medicine, said polio was a threat as far back as the 1930s and 1940s. "I can remember standing on the running board of my father's car, begging him to let me go to the movies. He wouldn't let me because of the risk of getting polio," Seidel said.
Sydenham Hospital, a city-run facility on Harford Road, had a ward filled with patients in iron lungs, many of them children, Seidel said. The hospital also had its own, red trucklike ambulances because city emergency crews were reluctant to transport polio patients for fear of becoming infected.
"We washed our hands a lot, I'll say that," recalled Seidel, who worked at Sydenham periodically from 1946 to 1953.
Hand washing was only one precaution doctors observed. As a researcher who worked with polio patients at Massachusetts General Hospital in Boston in the 1950s, Littlefield said he took a shower before he left the hospital every day. "My wife would make me take it before I came into the house," he said.
The original Salk injection vaccine - and the oral vaccine developed by Albert Sabin that was approved seven years later - combined to conquer a disease that was crippling and killing worldwide.
To many, the numbers represented a miracle. In 1952, there were 57,879 cases of polio, the worst year in U.S. history. Some 3,145 polio victims died that year and 20,000 were left crippled.
By the 1960s, the number of new polio cases had dropped into the dozens nationwide. By 1969, there wasn't a single U.S. polio death, and the disease has been eradicated in all but a dozen developing countries.
Polio belongs to a family of endoviruses that attacks the gut and nervous system. There are three strains of polio, all spread by respiratory droplets and fecal matter. Despite the fear the virus provoked, most polio victims were never paralyzed, and far fewer died. Many felt only a few ill effects, UM's Calia said.
In fact, as medical students, Calia and his classmates tested their own blood for polio. Several had been infected without knowing it, including Calia himself. "It's actually a very, very common infection," he declared.
Even so, for many, the Salk and Sabin vaccines were too late. There were 1 million survivors of polio in the United States in 1996, the year of the most recent federal count, according to Post-Polio Health International, a St. Louis group that helps survivors.
The National Health Interview Survey showed about 450,000 of the people who had contracted polio were suffering from paralysis or some other disability, according to Joan Headley, the group's executive director.
Some polio victims recovered, shedding braces and regaining the ability to walk and use their limbs. One of them is Nickie Lancaster, 63, a nurse who runs a support group for polio survivors in Nashville, Tenn. She contracted polio at the age of 8, in 1950 and was bedridden for two years.
Once word got out that she had polio, her father's grocery store was quarantined and ordered closed by local health authorities for several days - a common practice, Lancaster said.
"People don't understand the fear that was connected with polio. There's nothing like it now," she said.
Eventually, Lancaster regained the use of her legs and arms, graduated from nursing school, married and raised five children.
"I could never run and jump the way I once did, but I get around OK," she said.
Not everyone was so lucky. Jean Williams, who moved to Columbia to take a job with the Department of Defense in 1979, remains in a wheelchair, and has arms that were weakened by the polio that struck her in 1958. At the time, she was a 15-year-old student in Columbus, Ohio.
She learned to write left handed, earned a bachelor's degree and a master's from Ohio State University and now works as a language specialist for the Department of Defense. When she tells people that polio put her in a wheelchair, she gets mixed reactions.
"Some younger kids say, 'What's that?'" she said.
In the 1980s, researchers confirmed that some polio survivors were susceptible to long-lasting complications that can include fatigue, intolerance to cold, difficulty walking and a loss of muscle control in the legs and feet.
The polio that infected people in the 1940s and '50s destroyed many nerve cells, a loss that aggravates the normal decay of nerve cells that is part of the aging process, experts say.
"It's like being hit with polio all over again," said Williams, whose carpal tunnel syndrome is a post-polio complication.