in some area in alaska ( see the paper ) : 50 or 90% deaths
queensland, aborigenals : > 50% deaths
http://www.ed.lu.se/papers/mamelund.pdf
Geography May Explain the Adult Mortality from the 1918-20 Influenza Pandemic
The influenza pandemic of 1918-20 is one of the most deadly in history, with an
estimated 50 million deaths1. In previously exposed populations, influenza kills
young children and the elderly, giving the mortality curve a U-shaped age-profile. In
1918-20, however, mortality was W-shaped with additional peak around age 302.
Although the genomes of the virus (A/H1N1) have been reconstructed3 and the
lethality confirmed in animal studies4, the underlying causes of the age-pattern are
unknown. However, studies in contemporary epidemiology5, recent theoretical
immunology6 and empirical epidemiology/demography7-9, suggests that the increase
in mortality from age 15 to 30 and the decrease in mortality from age 30 to 60 is
explained by a combination of high virulence and that cohorts <30 years were
immunologically na?ve, while cohorts >30 years gained immunity from exposure to a
H1-like virus in circulation prior to the 1889-90 pandemic. The reason why children
5-14 years had low mortality despite lack of immunity is not well understood, but
persons >60 years may have had increased mortality risks because immunity was
compromised by aging6. Here it is tested whether populations who may have
escaped infection prior to 1889-90 due to isolation do not experience a decline in
mortality after age 30. Results shows that remote, indigenous populations in Alaska,
Labrador, Greenland, Australia and the Pacific, display V or square-root-shaped
age profiles in mortality (i.e. weak or no decline in mortality after age 30), and
therefore they may have been immunologically na?ve to the 1918-20 virus. This
finding strongly supports the idea that no or little previous exposure to a H1-like
influenza virus, due to remoteness, may explain mortality pattern of individuals 30-
60 years. This may also contribute to explain why some aboriginal villages
experienced extreme mortality levels. Clearly, knowledge about the age pattern of
mortality in historical influenza outbreaks is important for preparedness planning.
queensland, aborigenals : > 50% deaths
http://www.ed.lu.se/papers/mamelund.pdf
Geography May Explain the Adult Mortality from the 1918-20 Influenza Pandemic
The influenza pandemic of 1918-20 is one of the most deadly in history, with an
estimated 50 million deaths1. In previously exposed populations, influenza kills
young children and the elderly, giving the mortality curve a U-shaped age-profile. In
1918-20, however, mortality was W-shaped with additional peak around age 302.
Although the genomes of the virus (A/H1N1) have been reconstructed3 and the
lethality confirmed in animal studies4, the underlying causes of the age-pattern are
unknown. However, studies in contemporary epidemiology5, recent theoretical
immunology6 and empirical epidemiology/demography7-9, suggests that the increase
in mortality from age 15 to 30 and the decrease in mortality from age 30 to 60 is
explained by a combination of high virulence and that cohorts <30 years were
immunologically na?ve, while cohorts >30 years gained immunity from exposure to a
H1-like virus in circulation prior to the 1889-90 pandemic. The reason why children
5-14 years had low mortality despite lack of immunity is not well understood, but
persons >60 years may have had increased mortality risks because immunity was
compromised by aging6. Here it is tested whether populations who may have
escaped infection prior to 1889-90 due to isolation do not experience a decline in
mortality after age 30. Results shows that remote, indigenous populations in Alaska,
Labrador, Greenland, Australia and the Pacific, display V or square-root-shaped
age profiles in mortality (i.e. weak or no decline in mortality after age 30), and
therefore they may have been immunologically na?ve to the 1918-20 virus. This
finding strongly supports the idea that no or little previous exposure to a H1-like
influenza virus, due to remoteness, may explain mortality pattern of individuals 30-
60 years. This may also contribute to explain why some aboriginal villages
experienced extreme mortality levels. Clearly, knowledge about the age pattern of
mortality in historical influenza outbreaks is important for preparedness planning.
)
