What Do Cows and Vaccines Have in Common? It's All in the Name

Hello Everyone,

As we learned this week from Roger's talk, rotavirus-caused diarrhea can be prevented in some children through vaccination.  So what is vaccination, anyway?  In the 18th century, English medic Dr. Edward Jenner noted that milk maids were typically unblemished with facial scars when smallpox affected the population where the milk maids lived and worked.  Jenner's observation was that milk maids would become infected with cowpox, a mild disease acquired while touching the infected udders of milk cows. Hence, the well-known adulation "she has the complexion of a milk maid."

Smallpox victim

Jenner deduced that cowpox infection conferred immunity in the milk maids to the much more disfiguring and deadly (30% fatality rate) smallpox or "variola" infection.  Thus, in the late 1790s, Jenner began a program of "vaccination" (a term derived from the Latin "vacca" for cow) using the pustules of cowpox (now known to contain vaccinia virus), creating the first effective and safe inoculation against deadly smallpox.  

However, it took some 50 years before this technique of deliberately infecting someone with the milder vaccinia virus was accepted by suspicious health practitioners steeped in traditional beliefs and mysticism.

Previously, in the 1700s "variolation" was the technique of choice, whereby dried scabs from smallpox victims were ground into a powder that was blown into the nose of those uninfected.  This did indeed confer immunity to smallpox, but up to 2-3% of "variolated" individuals died as a result. Thus, "vaccination" was the much safer and effective alternative to "variolation," as described in this short TED-Ed talk.

Ali Maow Maalina

The last naturally-occurring case of smallpox in the world was contracted in October, 1977 by Ali Maow Maalina,  a young man in Merka Town, Somalia.  Ali survived his smallpox infection and went on to dedicate himself to eradicating polio until his death last year, as reported on NPR.  In 1980 the World Health Organization certified that smallpox was eradicated from Earth.

The NIH National Library of Medicine offers an excellent historical review of the smallpox eradication campaign of the 1960s and 70s.

However, smallpox is the only disease affecting humans for which such an accomplishment has been successfully achieved, though feverish efforts are currently underway to eradicate poliomyelitis, whose champion is the Gates Foundation, and dracunculiasis, whose champion is the Carter Center.  Global eradication programs in the past have also targeted hookworm, malaria, yaws, and yellow fever, but without success.

Nonetheless, since the days of Jenner, vaccination has been tremendously successful in preventing the morbidity and mortality caused by many infectious diseases (see this fascinating vaccines timeline), and reduces associated disability, economic loss, and poverty, as described in this 2008 review article in the WHO Bulletin. 

Source: CDC, MMWR, 5 Apr 2014

Yet, like many public health successes, once a problem is controlled it is no longer seen and is therefore not perceived to be a problem by some.  Public complacency and even disbelief arise, particularly in developed countries where some advocate against vaccination.  The result is outbreaks of vaccine-preventable measles, mumps, and pertussis, for example, and associated medical/hospitalization costs and disability, e.g., mumps in adolescent and young adult men may cause sterility. 

Qs:  What are the key influences that cause someone to get themselves or their child vaccinated?  What are the barriers to vaccination acceptance?  Should vaccines be subsidized by governments, so that everyone, everywhere could be fully immunized at no or low cost on schedule?  Should people be free to choose to NOT be vaccinated?  What are the risks associated with this freedom of choice?

Take care and see you next week,

Jim