The 1918 influenza pandemic in New York City: age-specific timing, mortality, and transmission dynamics

[tetano]

Influenza Other Respir Viruses. 2013 Dec 2. doi: 10.1111/irv.12217. [Epub ahead of print]
The 1918 influenza pandemic in New York City: age-specific timing, mortality, and transmission dynamics.
Yang W, Petkova E, Shaman J.
Source

Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA.
Abstract
BACKGROUND:

The 1918 influenza pandemic caused disproportionately high mortality among certain age groups. The mechanisms underlying these differences are not fully understood.
OBJECTIVES:

To explore the dynamics of the 1918 pandemic and to identify potential age-specific transmission patterns.
METHODS:

We examined 1915-1923 daily mortality data in New York City (NYC) and estimated the outbreak duration and initial effective reproductive number (Re ) for each 1-year age cohort.
RESULTS:

Four pandemic waves occurred from February 1918 to April 1920. The fractional mortality increase (i.e. ratio of excess mortality to baseline mortality) was highest among teenagers during the first wave. This peak shifted to 25- to 29-year-olds in subsequent waves. The distribution of age-specific mortality during the last three waves was strongly correlated (r = 0?94 and 0?86). With each wave, the pandemic appeared to spread with a comparable early growth rate but then attenuate with varying rates. For the entire population, Re estimates made assuming 2-day serial interval were 1?74 (1?27), 1?74 (1?43), 1?66 (1?25), and 1?86 (1?37), respectively, during the first week (first 3 weeks) of each wave. Using age-specific mortality, the average Re estimates over the first week of each wave were 1?62 (95% CI: 1?55-1?68), 1?68 (1?65-1?72), 1?67 (1?61-1?73), and 1?69 (1?63-1?74), respectively; Re was not significantly different either among age cohorts or between waves.
CONCLUSIONS:

The pandemic generally caused higher mortality among young adults and might have spread mainly among school-aged children during the first wave. We propose mechanisms to explain the timing and transmission dynamics of the four NYC pandemic waves.

? 2013 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.
KEYWORDS:

Age-specific mortality, cross-immunity, effective reproductive number, influenza pandemic, transmission dynamics

PMID:
24299150
[PubMed - as supplied by publisher]

http://www.ncbi.nlm.nih.gov/pubmed/24299150

 

[gsgs]

did I miss this ? I don't remember. They got 1918 P+I deaths by single-year-of-age from New York !
I remember the same from Indiana,Kansas,Philadelphia, Montreal,Toronto,Kentucky (what else?) before
And they got the data from the genealogy people, scanning death certificates.
Wasn't there the day/month of birth in 1918 New York death certificates ? What we need is to compare
death rates from people born before and after a flu wave i.e. 1889,1875,

Of course, best would have been if people had reported when they got the flu in 19th century

-----------------------------------------------------
We obtained historical daily mortality data from the
Genealogy Federation of Long Island. Death certificates
between 1915 and 1923 in all NYC boroughs (Bronx,
Brooklyn, Manhattan, Queens, and Staten Island) were
scanned with permission and entered into a database with
careful proofreading and validation. Mortality of all persons
1 year and older was included in the analysis. More details
are available in the Appendix S1
======================================================


http://onlinelibrary.wiley.com/doi/1...irv.12217/full
http://onlinelibrary.wiley.com/doi/1.../irv.12217/pdf

The 1918 influenza pandemic in New York City: age-specific timing, mortality, and transmission dynamics

Wan Yang*,
Elisaveta Petkova and
Jeffrey Shaman
Article first published online: 2 DEC 2013
DOI: 10.1111/irv.12217