Bullfrag EU sets new guidelines on vaccines and face masks for federal employees Reuters.- Federal workers and contractors in situ They will have to show proof of vaccination against Covid-19 or wear face masks, practice social distancing and undergo regular tests, according to new guidelines announced Thursday by the White House. The measures are the latest effort by US President Joel Biden to encourage some reluctant Americans to get vaccinated, as the Delta variant of the coronavirus is wreaking havoc especially among the unvaccinated. Public employees who cannot prove they are vaccinated will be subjected to weekly or biweekly tests for Covid-19 and restrictions on official travel.