Twenty years of recrudescent influenza and pneumonia mortality after the 1918 influenza pandemic in Newfoundland

Le résumé fourni par la source

There is substantial and growing knowledge of the severe and unequal impacts of the 1918 flu worldwide, but the long-term impacts of the pandemic have not been studied widely despite its unique epidemiological signatures. The goal of this paper is to identify significant recrudescent influenza and pneumonia (P&I) mortality events after the 1918 flu through 1939 in Newfoundland, with specific attention to the changes in age-based mortality. I use a Serfling regression model using monthly P&I mortality rates from 1910-17 to identify baseline patterns preceding the 1918 flu. I assess monthly P&I mortality rates from 1918-39 against the baseline Serfling regression model to identify months of significant excess P&I mortality rates for the ~20 post-pandemic years. I calculate a ratio of excess mortality in <65-year-olds and excess mortality in 65+-year-olds (RR <>65 ) to identify major shifts in age-based P&I mortality during and after the flu pandemic. Results show that there were six significant recrudescent P&I mortality events after the 1918-20 flu in 1923, 1926, 1928, 1929, 1931, and 1935 (18 months of excess P&I mortality and ~1548 excess deaths). Age-based analyses (RR <>65 ) show that individuals <65 had highest excess mortality during the flu pandemic RR <>65 reverted to <1.0 in the following years, with some important exceptions. These results suggest that the novelty of the H1N1 influenza A virus in 1918 contributed to significant long-term P&I activity and recrudescent mortality in Newfoundland for at least two decades after the end of the pandemic.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.