Washington, March 7 -- Scientists at the US Food and Drug Administration (FDA) are strongly against administering only single doses of the Moderna and Pfizer vaccines, as their efficacy has only been proven if people get two shots, The Wall Street Journal reports.

"It is essential that these vaccines be used as authorized by FDA in order to prevent Covid-19 and related hospitalizations and death," Peter Marks, director of the FDA center that oversees vaccines, told The Wall Street Journal on Saturday.

In February, some scientists and lawmakers suggested using a one-dose regimen for all coronavirus vaccines approved in the US, after certain preliminary studies showed that a single shot could be enough for some people.

At the end of Febr...