Science & Technology in Action

13th Edition

Vaccines: Separating fact from fiction

Health Service Executive

Why do people reject evidence? When people have their minds made up in advance they reject real evidence in favour of a belief, even when that belief is shown to be without foundation. People sometimes fail to distinguish between coincidence and causation.
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Lesson excerpt

Pellagra: a true story

In the early 20th century in the southern USA up to 5000 people a year were affected by a debilitating disease called pellagra and up to 40% of them died as a result. At the time it was unclear what caused the disease but it was assumed to be contagious because members of the same family were often afflicted. However, pellagra was uncommon among children younger than 2 years of age, older adolescents and active men. A study (published in 1913) by Dr R.M. Grimm found that the disease was associated with poverty and poor sanitation. The following year Joseph Goldberger, a respected epidemiologist, was appointed to investigate the disease. Within a few months he was convinced that it was not contagious. He noted that pellagra was common among inmates of ‘mental institutions’ but not among the nurses and staff. To prove his case Goldberger chose three state institutions in which pellagra had been endemic for years. Beginning in September 1914 he had the diets changed to include fresh animal foods and legumes. The following spring, there was only one recurrence among the 245 patients, there was no new case and 244 were cured. But Goldberger’s conclusions were not accepted. So, he conducted further large scale studies that demonstrated that pellagra was a dietary disease and was completely preventable. Still the southern authorities and the people felt that his conclusions insulted their way of life. As a result nothing was done to improve the living conditions of the poor and Goldberger was relieved of his duties. In the 1920s he continued his research to find out exactly what caused pellagra. He discovered that a small amount of yeast in the diet was just as effective as fresh milk, meat and vegetables in preventing pellagra. In 1927, on his advice, the Red Cross distributed dried yeast to Mississippi flood victims and successfully prevented a pellagra epidemic. Sadly Joseph Goldberger died of cancer in January 1929. Eventually in 1937 it was shown that absence of niacin in the diet was the cause of pellagra. Niacin is present in yeast and in foods such as meat, fruit and potatoes. Nowadays it is routinely added to flour.

True or False?

  1. The story of Joseph Goldberger shows that people accept facts when proof is provided. false
  2. When events occur around the same time then one is the cause of the other. false
  3. There are more than 200 types of HPV virus. true
  4. Two types of HPV cause 70% of cervical cancers. true
  5. More than ten types of HPV cause genital cancers. true
  6. In Ireland over 250 women need treatment for invasive cervical cancer every year. true
  7. Every year about 600 women in Ireland need hospital treatment for a precancerous form of cervical cancer. false
  8. The adaptive immune system is activated by vaccines. true
  9. Cervical cancer is completely preventable. true
  10. Every year in Ireland about 90 women die from cervical cancer. true

Glossary of terms

Adaptive immunity
adaptive immunity (= acquired immune) provides long lasting protection against specific pathogens
Antibodies
Proteins produced by lymphocytes in response to a particular antigen
Causation
a relationship between events in which one event causes the other, or at least contributes to it
Cervical cancers
cancers of the cervix or 'neck of the uterus'
Coincidence
happening at the same time
Contagious
A disease that can be transmitted readily between people
Epidemiologist
a person who specialises in the study of epidemics
HSE
Health Service Executive (in Ireland)
Innate immunity
immunity that is 'built-in' rather than acquired
Invasive
a non-native species that establishes and displaces native species
Legumes
plants whose fruit is formed in pods; e.g. peas, beans, clover
Leucocytes
white blood cells
memory T cells
specialised white blood cell that fight infection (and possibly cancer) and 'remember' antigens they have previously attacked (also known as a T lymphocyte)
mental institutions
institutions in which patients with psychiatric illnesses were formerly treated (or just detained)
Niacin
an essential vitamin; also known as Vitamin B3
Pellagra
a serious disease resulting from lack of the vitamin niacin in the diet
Precancerous
a condition likely to lead to cancer if untreated
Virus
a very small disease-causing particle containing DNA which when it enters a cell typically redirects the cellular mechanism to produce more virus particles
Yeast
A unicellular fungus that reproduces asexually by budding.