WASHINGTON, Oct 14 (Reuters) - Verizon Communications In (VZ.N) said on Thursday that about 30,000 non-union U.S. employees must show proof of vaccination against COVID-19 by Dec. 8 under President Joe Biden"s federal contractor executive order. Verizon, a federal contractor, said it is in discussions with its unions about vaccination requirements. Verizon said retail employees and some other employees must be vaccinated by Feb. 1. For contractors, vendors, visitors and new hires who enter Verizon U.S. facilities must be fully vaccinated by Jan. 1.