Table 2. Association between mumps complications, hospitalisation, severe outcome and measles-mumps-rubella (MMR) vaccination status in mumps cases, Norway, September 2015–March 2016 (n = 207).

Complication or severe outcome	Doses of MMR vaccinations	Cases with complication	Total cases	%	Adjusteda RR (95% CI)	p-value
Hospitalisation	0	2	9	22	Ref	Ref
	1	0	13	0	0.00 (0.00–0.00)	< 0.001
	2	5	184	3	0.14 (0.03–0.57)	0.006
	3	0	1	0	0.00 (0.00–0.03)	< 0.001
Orchitisb	0	4	7	57	Ref	Ref
	1	0	10	0	0.00 (0.00–0.00)	< 0.001
	2	12	103	12	0.21 (0.08–0.55)	0.001
Severe casec	0	4	9	44	Ref	Ref
	1	0	13	0	0.00 (0.00–0.00)	< 0.001
	2	15	184	8	0.25 (0.10–0.62)	0.003
	3	0	1	0	0.08 (0.01–0.62)	0.016

CI: confidence interval; MMR: measles-mumps-rubella; RR: relative risk.

^aAdjusted for age (as continuous variable) and gender except for orchitis, which was adjusted only for age among males.

^bProportions and estimations for orchitis were calculated using data only from male cases with known vaccination status: 120 cases.

^cA severe case was defined as a case that was hospitalised or presented with any mumps-related complications (e.g. orchitis, meningitis).