COVID-19 vaccine effectiveness against symptomatic SARS-CoV-2 infection during Delta-dominant and Omicron-dominant periods in Japan: a multi-center prospective case-control study (FASCINATE study).
Takeshi ArashiroYuzo ArimaHirokazu MuraokaAkihiro SatoKunihiro ObaYuki UeharaHiroko AriokaHideki YanaiJin KuramochiGenei IharaKumi ChubachiNaoki YanagisawaYoshito NaguraYasuyuki KatoAkihiro UedaAkira NumataHideaki KatoKoji IshiiTakao OokiHideaki OkaYusuke NishidaAshley StuckyChris SmithMartin HibberdKoya AriyoshiMotoi SuzukiPublished in: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America (2022)
In Japan where most are infection-naïve and strict prevention measures are maintained regardless of vaccination status, 2-dose mRNA vaccines provided high protection against symptomatic infection during the Delta-dominant period and moderate protection during the Omicron-dominant period. Among individuals who received an mRNA booster dose, VE recovered to a high level.