By Manas Mishra and Michael Erman (Reuters) -Advisers to the U.S Food and Drug Administration on Wednesday unanimously recommended the agency authorize COVID-19 vaccines from Moderna Inc and Pfizer Inc/BioNTech SE for millions of the youngest American children. The committee’s recommendation is an important step toward immunizing children under the age of 5 and as young as 6 months old who have not yet been eligible for the shots. The FDA is likely to authorize the shots soon. The U.S. government is planning for a June 21 start to its under-5 vaccination campaign should the vaccines receive FD…