By Jennifer Rigby, Natalie Grover and Maggie Fick LONDON/KISUMU, Kenya (Reuters) – After decades of work, the World Health Organization endorsed the first-ever malaria vaccine last year – a historic milestone that promised to drive back a disease that kills a child every minute. In reality, efforts are falling well short of that, with a lack of funding and commercial potential thwarting GSK Plc’s capacity to produce as many doses of its shot as needed, according to Reuters interviews with about a dozen WHO officials, GSK staff, scientists and non-profit groups. The British drugmaker committed …