What New Yorkers can learn from past vaccination efforts

The coronavirus pandemic is hardly the only public health crisis to strike New York over the past four centuries. Typhus, smallpox and plague were part of the colonial experience. Outbreaks of cholera and yellow fever slammed the state as its population increased during the 19th century. More than 30,000 people died in New York City from the 1918 influenza pandemic alone. 

While vaccines have kept infectious diseases mostly under control in recent decades, they also provide some good examples of just how hard it is to eradicate infectious diseases. Vaccines take time to perfect and distribute. Delays happen. Safety concerns can persist for decades. Yet, the success of vaccines against diseases that once killed and maimed thousands of New Yorkers each year shows just how great the rewards are for an effective public health effort.

“Human beings have benefited from vaccines for more than two centuries,” reads one history of vaccinology. “Yet the pathway to effective vaccines has been neither neat nor direct.”

With COVID-19 raging again across the Empire State, past battles with four other infectious diseases offer a glimpse of how the distribution of vaccines against the coronavirus could play out for years to come. 

Cholera shows how long it takes to perfect a vaccine.

One 19th-century outbreak of this bacterial disease – which causes diarrhea, dehydration and death – still ranks as one of the biggest mass death events in New York City history. The development of a vaccine by the end of that century meant that fewer people continued to die from contaminated food and water. Yet, the subsequent decades show just how long it can take to improve a vaccine enough to really get the disease under control. The U.S. did not ease travel restrictions related to the disease. Combining cholera and other childhood shots into a single dose provided a big boost to vaccination efforts in the 1990s.

Measles highlights how vulnerable herd immunity can be. 

The first vaccines for this highly infectious virus appeared in the 1960s. By the mid-1980s, its trademark rash and fever ceased being a regular occurrence for American schoolchildren, though sporadic outbreaks continued. While the virus was eliminated from the United States by the turn of the century, concerns about the safety of the vaccine (however much debunked by scientists) allowed the virus to regain a foothold in the country. New vaccine requirements have helped New York keep vaccination rates above the 90-95% required to maintain herd immunity against measles, but the associated political controversies have shown just how tricky it can be to keep things under control.

Polio demonstrates how safety concerns can plague a public health effort for years.

The vaccine against polio was a huge success for public health, especially considering how tens of thousands of children were once disabled every year by this fecal-based virus. However, there have been more than a few bumps in the road to success. The distribution of a vaccine developed through the research of Jonas Salk (don’t blame him for this infamous incident) was delayed for months after at least 250 children got infected with a live polio virus in 1955. The American Medical Association was still getting criticized over safety concerns six years later. One Syracuse man got more than a half-million dollars in a settlement a few years later after a Pfizer vaccine crippled him. And legal issues related to the safety of polio vaccines persisted into a new century.

Smallpox underscores how total victory is possible.

Vaccines are not perfect, but they have transformed the world irrevocably for the better. Take smallpox, which used to be one of the scourges of all humanity. More than 30% of people would die once they came anywhere near this highly contagious virus that would cause skin rashes to become fluid-filled blisters – not the ancient Chinese, nor the crusaders – and certainly not the indigenous civilizations in the Americas, Australia and elsewhere that were ravaged by smallpox and other infectious diseases brought by Europeans. Except for a few laboratory specimens, there have been no new cases of smallpox worldwide since 1978, which makes it the only major infectious disease to have been fully eradicated – a welcome reason for optimism during tough epidemiological times.