Vaccination is one of the greatest advancements in public health, saving hundreds of millions of lives in the past century.

But ironically, the very success of vaccination has given some a case of historical amnesia, doctors say. Rising, unfounded skepticism about the benefits of vaccines have led to outbreaks of once-rare diseases in recent years.

“People know about these diseases as mythic dragons. Years ago, you built castles and moats and city walls to keep those monsters out,” said Dr. Sean Palfrey, a pediatrician at Boston Medical Center, above. “We try not to terrify people, but if they're saying these things aren't important anymore, we have to remind them they're out there, and if we let down our guard, they will break in and maul us.”

Coverage spoke with clinicians and loved ones of those who suffered from illnesses that vaccines have since made rare, including measles, smallpox, polio and meningitis B. Their words offer a powerful reminder of the vital importance of vaccination.

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Today, Americans seldom know what diphtheria is, thanks to the vaccine developed in the 1920s.

The disease, commonly referred to in days past as “throat distemper,” caused dead, gray tissue to build up in the throat. It ultimately blocked the patient’s airway, making it difficult to breathe, according to the World Health Association. Children were particularly susceptible.

“It was a really unpleasant and frightening disease,” according to James Colgrove, a public health historian at Columbia University. “When a kid got diphtheria, this leathery membrane would grow around the inside of the throat, and the throat became so clogged, kids sort of choked to death from within.”

One of the most massive epidemics to hit New England was The Great Throat Distemper of 1735-1740, according to the New England Historical Society. It mostly claimed the lives of children, and only took about three days to cause death.

“In Ipswich, all eight children in the household of Mark and Hephzibah How died during the month of November 1735,” according to the Historical Society. “A neighbor family also reported losing all eight children. As many as four children were buried in a single grave, a fact that was noted in newspapers as far away as New York.”

The disease continues to appear sporadically in areas with limited access to the vaccine, including Indonesia, Bangladesh, Myanmar, Vietnam, Venezuela, Haiti, South Africa and Yemen. According to the CDC, there have been about 7,100 cases globally since 2016. In the past decade, there have been fewer than five cases in the U.S., where children are vaccinated as infants against the disease.

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^{PHOTO OF Dr. SEAN PALFREY BY NICOLAUS CZARNECKI}