Vaccines have become the most important weapon in the fight against the COVID-19 pandemic, but antibody levels after vaccination decay quickly over time.
© Provided by Xinhua HARBIN, April 26 (Xinhua) Old-school workshops built with red bricks, sculptures made from rusty manufacturing components, and
© Provided by Xinhua HARBIN, April 26 (Xinhua) Old-school workshops built with red bricks, sculptures made from rusty manufacturing components, and