Influenza-related mortality trends in japanese and american seniors: Evidence for the indirect mortality benefits of vaccinating schoolchildren

Vivek Charu, Cecile Viboud, Lone Simonsen, Katharine Sturm-Ramirez, Masayoshi Shinjoh, Gerardo Chowell, Mark Miller, Norio Sugaya

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Abstract

Background
The historical Japanese influenza vaccination program targeted at schoolchildren provides a unique opportunity to evaluate the indirect benefits of vaccinating high-transmitter groups to mitigate disease burden among seniors. Here we characterize the indirect mortality benefits of vaccinating schoolchildren based on data from Japan and the US.

Methods
We compared age-specific influenza-related excess mortality rates in Japanese seniors aged ≥65 years during the schoolchildren vaccination program (1978–1994) and after the program was discontinued (1995–2006). Indirect vaccine benefits were adjusted for demographic changes, socioeconomics and dominant influenza subtype; US mortality data were used as a control.

Results
We estimate that the schoolchildren vaccination program conferred a 36% adjusted mortality reduction among Japanese seniors (95%CI: 17–51%), corresponding to ∼1,000 senior deaths averted by vaccination annually (95%CI: 400–1,800). In contrast, influenza-related mortality did not change among US seniors, despite increasing vaccine coverage in this population.

Conclusions
The Japanese schoolchildren vaccination program was associated with substantial indirect mortality benefits in seniors.
OriginalsprogEngelsk
TidsskriftP L o S One
Vol/bind6
Udgave nummer11
ISSN1932-6203
StatusUdgivet - 2011

Citer dette