Covid-19 booster shots remain a bone of contention between the World Health Organisation (W.H.O) and the health officials of the United States. Amid W.H.O’s call for vaccinating the vulnerable first, the United States authorised booster shots for all Americans from next month. US President Joe Biden said he will make Covid-19 booster shots available to all Americans beginning September 20, as his administration warned that vaccines are showing declining effectiveness against infection. Meanwhile, W.H.O Chief scientist Dr. Soumya Swaminathan warned of dire situations worldwide. Watch the full video for more.