Health officials are warning that confirmed cases of measles may have spread at this year's National March for Life rally and concert in Washington, D.C. Thousands of anti-abortion demonstrators converged upon the National Mall and other locations in the nation's capital for the annual event at the end of January. The DC Department of Health says it's working to identify people who are at risk. "DC Health was notified of multiple confirmed cases of measles whose carriers visited multiple locations in the District while contagious," the agency said in a press release on Sunday. "DC Health is informing people who...