Can cases and outbreaks of norovirus in children provide an early warning of seasonal norovirus infection: an analysis of nine seasons of surveillance data in England UK

Table 3 Spearman’s rank partial correlation, comparing outbreaks in schools in relation to listed surveillance indicator, controlled for school holidays

Relative temporal position of school outbreaks in relation to listed dataset	Lead time					Lag time
	+ 4 weeks	+ 3 weeks	+ 2 weeks	+ 1 week	Concurrent	-1 week	-2 weeks	-3 weeks	-4 weeks
Care home outbreaks	0.73	0.76	0.73	0.68	0.61	0.46	0.42	0.33	0.25
Hospital outbreaks	0.73	0.77	0.72	0.67	0.61	0.50	0.41	0.34	0.30
Laboratory norovirus reports	0.68	0.69	0.64	0.59	0.52	0.43	0.35	0.23	0.16
NHS 111 calls for diarrhoea^c	0.54	0.59	0.55	0.34	0.22	0.06	0.00	-0.02	-0.10
NHS 111 calls for vomiting^c	0.63	0.76	0.80	0.69	0.60	0.48	0.41	0.38	0.30
GP consultations^ab	0.16	0.24	0.24	0.52	0.55	0.48	0.37	0.21	0.23

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