Background  The origin and estimated death toll of the 1918–1919 epidemic are still debated. Europe, one of the candidate sites for pandemic emergence, has detailed pandemic mortality information. Objective  To determine the mortality impact of the 1918 pandemic in 14 European countries, accounting for approximately three‐quarters of the European population (250 million in 1918). Methods  We analyzed monthly all‐cause civilian mortality rates in the 14 countries, accounting for approximately three‐quarters of the European population (250 million in 1918). A periodic regression model was applied to estimate excess mortality from 1906 to 1922. Using the 1906–1917 data as a training set, the method provided a non‐epidemic baseline for 1918–1922. Excess mortality was the mortality observed above this baseline. It represents the upper bound of the mortality attributable to the flu pandemic. Results  Our analysis suggests that 2·64 million excess deaths occurred in Europe during the period when Spanish flu was circulating. The method provided space variation of the excess mortality: the highest and lowest cumulative excess/predicted mortality ratios were observed in Italy (+172%) and Finland (+33%). Excess‐death curves showed high synchrony in 1918–1919 with peak mortality occurring in all countries during a 2‐month window (Oct–Nov 1918). Conclusions  During the Spanish flu, the excess mortality was 1·1% of the European population. Our study highlights the synchrony of the mortality waves in the different countries, which pleads against a European origin of the pandemic, as was sometimes hypothesized.

Please cite this paper as: Boëlle P‐Y et al. (2011) Transmission parameters of the A/H1N1 (2009) influenza virus pandemic: a review. Influenza and Other Respiratory Viruses 5(5), 306–316. Background  The new influenza virus A/H1N1 (2009), identified in mid‐2009, rapidly spread over the world. Estimating the transmissibility of this new virus was a public health priority. Methods  We reviewed all studies presenting estimates of the serial interval or generation time and the reproduction number of the A/H1N1 (2009) virus infection. Results  Thirteen studies documented the serial interval from household or close‐contact studies, with overall mean 3 days (95% CI: 2·4, 3·6); taking into account tertiary transmission reduced this estimate to 2·6 days. Model‐based estimates were more variable, from 1·9 to 6 days. Twenty‐four studies reported reproduction numbers for community‐based epidemics at the town or country level. The range was 1·2–3·1, with larger estimates reported at the beginning of the pandemic. Accounting for under‐reporting in the early period of the pandemic and limiting variation because of the choice of the generation time interval, the reproduction number was between 1·2 and 2·3 with median 1·5. Discussion  The serial interval of A/H1N1 (2009) flu was typically short, with mean value similar to the seasonal flu. The estimates of the reproduction number were more variable. Compared with past influenza pandemics, the median reproduction number was similar (1968) or slightly smaller (1889, 1918, 1957).

This is the largest series to our knowledge of streptococcal PJI managed by DAIR, showing a worse prognosis than previously reported. The beneficial effects of exchanging the removable components and of β-lactams are confirmed and maybe also a potential benefit from adding rifampin.