Decrease in effectiveness of routine surveillance of Haemophilus influenzae disease after introduction of conjugate vaccine: comparison of routine reporting with active surveillance system.

We thank Debbie Sen, Dr Judith Rankin, and Marjorie Renwick of the Regional Maternity Survey Office, Newcastle upon Tyne for their help in compiling the Northern region data and Vicki Ashton of Teesside University for statistical advice. Contributors: GH had the original idea for the study and coordinated the data analysis. LMI supplied the data from Norway. RTL supplied the statistical expertise. The paper was written jointly by GH, LMI, and RTL. Conflict of interest: None. 1 Hawthorne G, Robson S, Ryall EA, Sen D, Roberts SH, Ward Platt MP. Prospective population based survey of outcome of pregnancy in diabetic women: results of the Northern Diabetic Pregnancy Audit, 1994. BMJ 1997;315:279-81. 2 Casson IF, Clarke CA, Howard CV, McKendrick O, Pennycook S, Pharoah POD, et al. Outcomes of pregnancy in insulin dependent diabetic women: results of a five year cohort study. BMJ 1997;315:275-8. 3 Hadden DR, McCance D, Traub AI. Ten year outcome of diabetic pregnancy in Northern Ireland: the case for centralisation. Diabetic Med 1998(suppl 1);15:S16. 4 Hellesen HB, Vikane E, Lie RT, Irgens LM. Maternal diabetes: falling perinatal mortality but still high foetal growth. Tidsskr Nor Laegeforen 1996;116:3465-9. 5 Diabetes Care and Research in Europe: the Saint Vincent Declaration WHO/IDF Europe. Diabetic Med 1990;7:360.