Epidemiology of the Russian flu, 1889-1890

In an effort to extend the data set for influenza pandemic planning, Valleron, Cori, Meurisse, Carrat, and Boëlle gathered data from 15 countries in the northern hemisphere that experienced the ‘Russian flu’ pandemic in the winter of 1889-1890.

The pandemic was first recorded in St. Petersburg, Russia. Within a mere four months it had spread throughout the northern hemisphere. The mortality rate peaked in St Petersburg on December 1, 1889 and in the United States during the week of January 12, 1890. The median elapsed amount of time between the first reported case and peak mortality was five weeks.

Red = peak mortality, Green = past peak. (Valleron et al, PNAS May 11, 2010 vol. 107 no. 19 8778-8781 )

Valleron et al hypothesize that the speed of the transmission was due to the ‘connectedness’ of the cities rather than the mode of transport or the sheer number of travelers. European and American cities were better connected by railroads then than they are today by air and rail.

They found a clinical attack rate of 50% with a median basic reproduction number (R0) of 2.1 for the 96 cities studied. The case fatality rate for 1889 was 0.1 – 0.28% based on direct military data and indirect surveys. Direct data on case fatality rate was established from military reports from the French and British armies and indirect estimates come from the seven Swiss cities and the German army. A potential problem of relying so heavily on military data is that military men (in peacetime in 1889) should be among some of the healthier and robust in the population, while the very young, old, infirm and pregnant women usually fare the worst against influenza. With direct data excluding the most vulnerable it seems likely that the case fatality rate is on the low side. We also need an estimate of how often they correctly diagnosed influenza-like disease.

Based on this data, the 1889 pandemic appears to be similar to the mild pandemics of 1957, 1968 and 2009 and the ‘pseudo-pandemics’ of 1947, and 1977-78. The R0 of 2.0 and clinical attack rates of 30-60% is common among all pandemics from 1889 to 2009. Context does matter a great deal for the R0, so we really need to zoom in on the R0 in particular settings like school children, prisons, labor intensive factories, and the military. The 1918 pandemic stands out only in the case fatality rate (and this makes me wonder about the characteristics of secondary pneumonia in 1918).

We do need to keep in mind that this study only examines the first wave of the 1889 pandemic. This pandemic had staying power. Although it spread quickly in it’s first wave it continued to find susceptible victims for another four seasons until 1893.

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Valleron, AJ, Cori A, Valtat S, Meurisse S, Carrat F, & Boëlle PY (2010). Transmissibility and geographic spread of the 1889 influenza pandemic. Proceedings of the National Academy of Sciences of the United States of America, 107 (19), 8778-81 PMID: 20421481

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