Pfizer and BioNTech said Tuesday they are seeking emergency authorisation from US health regulators for use of their Covid-19 vaccine for children aged over six months and under five years. If the Food and Drug Administration (FDA) authorises the two-shot regimen, it will become the first Covid-19 vaccine available to this age group in the United States. The companies said Tuesday that they started submitting their formal application “following a request” from the FDA, which seemingly wants to get the process moving quickly. In a tweet soon after the announcement, the FDA said it will hold a m…