Archive for the ‘vaccination’ Category

Vaccination/immunization: Part 2 Smallpox: history

Wednesday, February 13th, 2013

We don't see these signs anymore.

Vaccines have a humble beginning. Smallpox was the first infection that people tried to prevent using a method called variolation, developed in China and India, in which dried material from a smallpox scab was ground up and then administered to a well individual, blowing the powder into their nose and hopefully giving them a mild case of smallpox and long-term immunity to the disease.

It originated from the observation that people who survived a previous smallpox infection somehow become resistant to getting the infection again. It was thought that by artificially infecting an unaffected person, the process could protect the individual from the dire malady.

Smallpox is an ancient disease; a great online article by Stefan Riedel, an MD, PhD from the Baylor University Medical Center, traces its history over an estimated 12,000 years, with Egyptian mummies from 3,000 to 3,500 years ago showing typical facial scars.

The Antonine Plague, which lasted from CE 165 to 180, most likely was smallpox (though possibly measles). It killed 2,000 per day in the Roman Empire with total deaths estimated at nearly seven million. Many scholars feel it significantly contributed to the downfall of the empire.

Ancient Chinese documents show that variolation was practiced in the Song dynasty in China (CE 960 to 1279). Legend has it that the Song emperor had lost his eldest son to smallpox, so he traveled deep into the forest of a high mountain and sought help from a reclusive nun. The woman was known as a holy healer, and she passed on the technique of variolation to save the ancient Chinese royal family.

Two to three percent of individuals receiving variolation ended up dying from smallpox. The only reason this practice continued was because the chance of dying from smallpox caught “naturally” from another infected person was much higher with some epidemics killing 30% or more of victims.

In 1717, Lady Mary Mortley Montagu, was in Constantinople as the wife of the British ambassador. She herself had suffered from smallpox and also lost a brother to the disease. She found that the Turks had another approach to gaining smallpox immunity, inoculation. The word is derived from the Latin inoculare, meaning “to graft.” Inoculation referred to the subcutaneous instillation of smallpox virus into non-immune individuals. The inoculator usually used a lancet wet with fresh matter taken from a ripe pustule of a person who suffered from smallpox. The material was then introduced into the arms or legs of the non-immune person.

Lady Montagu had two of her own children inoculated, one while in the Ottoman Empire and the other upon returning to England. A number of prisoners and later some abandoned children were subjected to the procedure; both Lady Montagu and the Princess of Wales were involved in this "research project," which next had those inoculated deliberately exposed to smallpox. None of them got the disease.

After this success, members of the British royal family were inoculated and the practice spread widely in Europe, reaching America with Reverend Cotton Mather being a strong supporter.

During one of Boston's succession of smallpox epidemics, after hearing from Cotton Mather of a publication in  the Transactions of the Royal Society, Dr Zabdiel Boylston, in spite of strenuous protests from the general public and from other physicians, inoculated his own son and two family servants. Eventually he performed the procedure on 247 ranging in age from nine months to sixty-seven years; other physicians inoculated 39, and of the 286 only six died  (2%) and three may have already had smallpox, while 14% of the 5,759 who had not been inoculated and caught the disease perished.

Thanks to Edward Jenner

The next step came from Dr. Edward Jenner, who had speculated about the protective effects of cowpox during his "apprenticeship" with George Harwicke. He had heard a woman who was a dairymaid and had a pock-free complexion say, "I shall never have smallpox because I have had cowpox." Over ten years later, in 1796, he used material from a cowpox-infected woman to inoculate an eight-year-old boy. The child recovered from cowpox, but when deliberately inoculated later with smallpox did not develop any signs or symptoms of the much more serious disease.

Since the Latin word for cow is vacca, Jenner dubbed the process vaccination and after being rejected for publication by the Royal Society, sponsored his own booklet to promote the method of smallpox prevention.

The rest, as they say, is history and Jenner became famous; in 1802 he received a large sum of money from Parliament and a still larger one in 1807. He continued his research in several areas of medicine and science and was appointed Physician Extraordinary to the King.

Vaccination became an established medical procedure.


Don't vacillate, vaccinate instead!

Wednesday, March 21st, 2012

Could she have measles?

The Wall Street Journal this morning had an article titled, "Where Could The Next Outbreak Of Measles Be?" A secondary heading on a later page said, "Low Vaccination Rates Trigger Fears," and there was a US map showing problem areas. Boulder, Colorado was one of those hot spots.

The article led me back to the concept of "herd immunity," very well illustrated on a webpage from the National Institute of Allergy and Infectious Diseases. Basically it says we need a relatively high percentage of a given population to be vaccinated (AKA immunized) against a given disease in order to prevent epidemics.

The particular viral disease I'm writing about is measles, sometimes called "red measles" or, technically, rubeola. The National Library of Medicine has an excellent, brief description of this ailment and notes that before widespread vaccination became common, most people had a case of measles before age 20.

Then the MMR vaccine was developed by a Merck scientist in the 1960s. Measles incidence went from being, as a 1954 quote termed it, "as inevitable as death and taxes," to an uncommon to rare disease in developed countries. In the US for the twenty years after the vaccine was licensed, an estimated 52 million overall cases, 17,400 leading to mental retardation and 5,200 deaths were prevented.

In 2000 the WHO estimated that there were still ~45 million cases of measles worldwide yearly causing 800,000 deaths. While mortality in developed countries was ~1/1000, in sub-Saharan Africa, mortality was 10%. In cases with complications, the rate could rise to 20–30%. On average, ~450 children died every day from measles. By 2007 immunizations had cut the yearly global death rate by 75%.

But in 1998 an article in The Lancet had caused a stir that has continued to this day. A British gastroenterologist reported a series of 12 young patients who were referred to his practice with bowel complaints. Their average age was six and 8 of them developed symptoms of autism within a month after they got their MMR injection.

Should I believe what I just read?

Many parents hearing about this report stopped their children's immunizations. This was in spite of numerous much larger studies showing no connection between MMR and autism. In 2005 a Japanese group showed an increase in autism diagnoses in children who got their childhood immunizations after the country's particular MMR vaccine was withdrawn from use because of a suspected side effect of the mumps component. In 2009 a review of multiple large studies was published examining three linkages that had been proposed: MMR and autism, thiomerosal (a mercury-based preservative chemical used in some vaccines, but not in MMR) and autism, multiple vaccinations and autism.

The accumulated data from these large groups in a number of countries showed no association between any of these factors and autism. Finally in 2010 The Lancet published a rather wishy-washy retraction of the Wakefield article.  His license had been revoked by the UK General Medical Council and the British Medical Journal's editorial staff published a much stronger condemnation of Wakefield's work in 2011, calling it fraudulent.

And yet today's WSJ article note parts of the US, especially in the northwest, have relatively poor compliance rates with vaccination guidelines. Parents can opt out because of medical, religious or even philosophical concerns. Low-income kids can receive free immunizations under a federally-funded programs, but one physician interviewed said the parents in his practice who don't want their kids vaccinated are wealthy and well-educated.

We've seen some minor outbreaks in the past few years. If we don't overcome parental misinformation and fears, we may have a major epidemic.