Risk of death from plague today and in history
Clinical bottom line
Today the chance of contracting plague is about 1 in 3 million, and of dying from it about 1 in 30 million.
In the two great plague pandemics of the mid 6th century and mid 14th century, the risk of dying from plague was greater than 1 in 2.
Data sources
- emedicine article on plague (www.emedicine.com/PED/topic1819.htm)
- Ole J. Benedictow. The Black Death, 1346-1353: The Complete History. Boydell Press, 2004.
Plague today
What the sources tell us
The population of the world is about 6.5 billion, though not all people live in areas where bubonic plague is likely to occur.
The number of cases of plague reported from the USA is small, with only 1 case in 2003 and 2 each in 2001 and 2002, none of which were fatal. This decline follows an increase in plague rates in the 1990s, with a high of 14 cases reported during 1994.
In recent years plague peaked at 5419 cases (274 fatal, 5%) in 1997; the incidence has since declined. In 2003, nine countries reported 2118 cases (182 fatal, 9%) to the WHO. Algeria reported cases of human plague for the first time in 50 years. India and Indonesia also recently reported cases after a 30- to 50-year quiescent period. Occurrence is probably underreported.
Mortality depends on the type of plague:
- Bubonic plague is fatal in about 50-70% of untreated cases, but perhaps 10-15% when treated.
- Septicaemic plague is almost 100% fatal, and perhaps 40% with treatment.
- Pneumonic plague is 100% fatal, regardless of treatment.
Give us the odds
Woldwide, the risk of contracting plague is low, at about 1 in 3 million, and with mortality even lower, at 1 in 30 million if treated.
Plague in history
What the sources tell us
Here the story is quite different. There have been two major pandemics that are likely to have been bubonic plague or a close variant. The first was the Justinian plague of the 540s, the second the Black Death of the 1340s. Both affected Europe, the Middle East, and for the Justinian plague south Asia and possibly China.
There is more documentary evidence on the medieval plague, and Benedictow's book is essentially a systematic review of mortality across Europe, as well as a fine discussion about the cause and nature of plague. In essence, about 60% of the population died in the first months of a plague visitation. Mortality was high - perhaps 100% in pregnant women and nursing mothers, and almost 100% in adolescents - particularly in country areas. Succeeding waves of plague and high mortality amongst the young meant that, in England for instance, the population 100 years after the plague's first visit was only 15% of what it was beforehand. Similar effects were evident for the Justinian plague, and both had major effects on the turn of history.
Give us the odds
In the ancient world, and in one of the great pandemics of the last two millenia, the chance of dying from plague was higher than 1 in 2.
Comment
There is an interesting contrast here. In the great pandemics, there was almost no chance of avoiding infection. Justinian himself was infected, but was one of the rare survivors. The Pope in Avignon avoided infection by, essentially, a policy of isolation. For the rest, the chance of infection was just about the same as the chance of dying.
Today, the chance of infection is miniscule, even where plague is endemic amongst the rodent population. But the chance of dying from plague if contracted, is still very high, even with treatment.
Figure 1: Risk of dying of plague today or in one of the great pandemics
Risk Communication Tool (c) John Paling 2000 (www.riskcomm.com)
