A federal health agency on Friday rejected the notion that a new variant of COVID-19 that originated in the United States exists. “Researchers have been monitoring U.S. strains since the pandemic began, including 5,700 samples collected in November and December,” a Centers for Disease Control and Prevention spokesman told news outlets. “To date, neither researchers nor analysts at CDC have seen the emergence of a particular variant in the United States as has been seen with the emergence of B.1.1.7 in the United Kingdom or B.1.351 in South Africa,” he added. The White House Coronavirus Task Force told states in a report last week that there may be a “USA variant” of COVID-19. “This fall/winter surge has been at nearly twice the rate of rise of cases as the spring and summer surges. This acceleration suggests there may be a USA variant that has evolved here, in addition to the …