(Vancouver, WA) -- More than 40-thousand people have now been vaccinated for COVID-19 at Washington state's four mass vaccination clinics. More than ten-thousand people received vaccines at the Clark County Fairgrounds in Ridgefield. This week, the Ridgefield, Wenatchee and Kennewick sites will prioritize second doses of the vaccine. Those sites administer the Pfizer vaccine, which requires a booster shot three weeks after the initial dose is administered.