By Alison Campbell 17/01/2016


I had another head-desk moment today, on reading a bit more of Judy Wilyman’s PhD thesis (a bit at a time is quite enough).

Smallpox vaccines
Smallpox vaccines. Flickr CC, Pan American Health Organization-PAHO / World Health Organization-WHO.

The document has quite a bit to say about smallpox. I’ve already noted the ill-considered statement that the vaccine has never been subject to clinical trials – a statement unaccompanied by any “now, I wonder why not?” explanation.

Incidentally, in commenting on that post, Tsu Do Nimh pointed out that there have been quite a few natural experiments that allow a comparison of morbidity and mortality between the vaccinated and non-vaccinated, beginning back in 18th-century Boston.

In this instance, the practice of variolation (using pus or scab material from someone recently infected) was used to protect people from smallpox; it was not as effective as modern vaccines and there were concerns that people still became ill and died.

However, the comparative statistics are compelling. There were 3 outbreaks of smallpox in Boston, in 1721, 1764, & 1792, During those outbreaks, the deaths per thousand cases of smallpox among the non-variolated ranged from 146 to 298. For the variolated group, deaths/1000 cases ranged from 9 to 20.

Wilyman must have missed this somehow.

But it gets worse.

It’s quite evident that Wilyman would prefer to attribute declines in rates of infection from diseases such as measles, polio and smallpox solely to ‘environmental’ factors, such as isolation of patients, along with better hygiene and nutrition. No-one would deny that these are important, but it’s also worth noting that 1950s America (ie the US) had high standards of both hygiene and nutrition – and fairly high rates of morbidity and mortality from measles. Nonetheless, she claims (p128 of the thesis proper) for smallpox that

isolation of the cases alone could have stopped the circulation of the virus and eradicated this disease
Why? Because, in her view
smallpox is only transferrable by direct skin-to-skin contact.
Now, while it’s true that the main route of transmission is face-to-face contact (and not skin-to-skin – the World Health Organisation notes that the virus can travel in saliva droplets on the breath of an infected person), that’s by no means the only route. As the Centres for Disease Control point out,

Smallpox can also be spread through direct contact with infected bodily fluids or contaminated objects such as bedding or clothing. Rarely, smallpox has been spread by virus carried in the air in enclosed settings such as buildings, buses, and trains.

That information was extremely easy to find. It’s surprising, to say the least, that the usual rigorous literature review required for a PhD thesis did not turn up the same information. And that the examiners didn’t notice its absence.

See other Sciblogs posts on the University of Wollongong thesis here.

Featured image: Flickr CC, Pan American Health Organization-PAHO / World Health Organization-WHO.