(FILES) In this file photo a healthcare worker fills a syringe with Pfizer Covid-19 vaccine at a community vaccination event in Los Angeles, California, August 11, 2021. – The US government will announce that Americans should get booster shots for coronavirus vaccines eight months after their last shot, part of a campaign that could begin as early as mid-September, according to US media. The move could be announced as early as this week, The New York Times reported, citing unnamed sources in President Joe Biden’s administration. (Photo by Robyn Beck / AFP)