Temporal associations between national outbreaks of meningococcal serogroup W and C disease in the Netherlands and England: an observational cohort study oleh Dr Mirjam J Knol, PhD, Susan J M Hahné, PhD, Jay Lucidarme, PhD, Helen Campbell, MSc, Hester E de Melker, PhD, Stephen J Gray, PhD, Prof Ray Borrow, FRCPath, Shamez N Ladhani, MRCPCH, Mary E Ramsay, FFPHM, Arie van der Ende, PhD