PROVIDENCE – The complexities and rapidly unfolding challenges of bringing coronavirus vaccines to Rhode Islanders were in sharp focus Friday during a morning virtual meeting of the state Health Department’s COVID-19 Vaccine subcommittee. A recent development -- surprise word on Thursday that the state will receive far fewer doses than expected of the Pfizer-BioNTech vaccine next week -- prompted committee facilitator McKenzie Morton, a member of the department’s COVID Vaccine Strategy and Planning Team, to declare “that’s a huge hit to the plan… We cannot pretend that we were not thrown for a loop.” Potentially balancing that is the anticipated emergency use authorization of the Moderna vaccine by the federal Food and Drug Administration on Friday. The FDA’s advisory panel on Thursday gave an overwhelming endorsement to the vaccine, and shipments could begin to Rhode Island and other states on Monday.