Diptheria, Polio, Relative Fear

I grew up next to a small 19th century cemetery that had a lot of child graves in it. There was one small obelisk that had the names of more than four children on its sides. It's fairly likely that diphtheria killed at least some of them, since it was a major killer of children under 5 before treatments and a vaccine were invented in the 20th century.

I was already planning to write about diphtheria, but discovered yesterday that it killed both Alice Neel's oldest brother and her first daughter, so that compelled me even more.

I started thinking about it recently when I was reading Mary Robinette Kowal's alternate-reality novel The Relentless Moon, which involves a plot related to the polio epidemic. I was born and grew up in the real world during the same years as the novel, and received both the Salk and Sabin vaccines. Despite that, I didn't know until now — as we live through another epidemic — that polio is not all that dangerous (relatively).

For instance, in 1952 when it was at its peak in the U.S., there were 58,000 recorded cases nationwide. Among those, 3,200 people died and 21,000 were left with mild to disabling paralysis.

According to the CDC site, 72 of 100 people infected with poliovirus have no visible symptoms, while about 25 of 100 have flu-like symptoms for two to five days. Many fewer than 1 in 100 (1–5 out of 1,000) develop more serious symptoms of the brain and spinal cord, including meningitis and paralysis. Among those with irreversible paralysis, 5–10% die; among the dead, the incidence rate is about six times higher for adults than children. So my image of the disease as a major risk to children was exaggerated.

South Dakota had the highest rate of the disease of any state. According to the South Dakota Argus Leader newspaper, part of the reason there was such a freak-out over polio was that the cause of its spread was unknown:

One of the many reasons why polio was such a feared disease is that no one knew how the disease was spread.... in spite of how dangerous and dreaded polio was, many doctors disliked all the emphasis placed on polio because it drew attention away from more serious health threats. Doctors knew that most of the people who had polio didn’t even know it, and those that did, most recovered with no disability.

They felt a much larger health threat was tuberculosis, which 34,000 people died from in 1950. Also, the deadly flu epidemic of 1957 killed 62,000. By contrast, 3,200 people died during 1952, the worst year of the polio epidemic.

Strangely enough, though, research showed that poor immigrant children who lived in unsanitary conditions were exposed to small amounts of the virus and became immune at an early age. Children from clean, middle-class homes, on the other hand, were at much greater risk of paralytic polio.

So it appears to be another example of the hygiene hypothesis. The transmission method, we know now, is oral-fecal. (Source: WHO) 

Diphtheria, on the other hand, had been a major killer of children long before the period of the big polio panic. It's from a bacteria spread through the air in respiratory droplets and from touching open sores. (Source: CDC) An untreated person is infectious for two to three weeks. 

The disease creates a toxin that kills healthy tissue in the respiratory system and forms a thick coating in the throat and nose, making it hard to breathe and swallow. The toxin can get into the bloodstream and cause organ and nerve damage. Without treatment, 1 in 2 people die.

According to History of Vaccines, in 1921 in the U.S., there were about 200,000 cases and 15,520 deaths. Effective diphtheria immunizations became available starting in the 1920s. Antibiotics were not used to treat it until the late 1940s, but there was an antitoxin that became available around the turn of the century. In 1921, death rates ranged from about 20% in children under age 5 and adults over age 40 to 5–10% for people ages 5–40. "Death rates were likely higher before the 20th century."

Alice Neel's brother died in the early 1900s and her daughter, Santillana, in 1927.