A medical worker prepares a dose of COVID-19 vaccine at Zagreb Fair in Croatia, on Dec. 27, 2021. (Igor Kralj/PIXSELL via Xinhua)
A woman receives a COVID-19 vaccine injection at Zagreb Fair in Croatia, on Dec. 27, 2021. (Igor Kralj/PIXSELL via Xinhua)
A man receives a COVID-19 vaccine injection at Zagreb Fair in Croatia, on Dec. 27, 2021. (Igor Kralj/PIXSELL via Xinhua)
A man receives a COVID-19 vaccine injection at Zagreb Fair in Croatia, on Dec. 27, 2021. (Igor Kralj/PIXSELL via Xinhua)
People wait to receive COVID-19 vaccine at Zagreb Fair in Croatia, on Dec. 27, 2021. (Igor Kralj/PIXSELL via Xinhua)
