Table 3. Calculated manifestation indices of tick-borne encephalitis, per region, Sweden, 2004–2019.

Region	Notified TBE case incidence^a	TBEV infection incidence^b	TBE MI (%)
Gotland	4.0	50.0	8.0
Gävleborg	1.1	50.0	2.2
Kronoberg	1.2	50.0	2.3
Skåne	0.8	66.7	1.3
Stockholm	6.6	350.0	1.9
Uppsala	13.1	150.0	8.7
Värmland	2.4	150.0	1.6
Västerbotten	0.2	50.0	0.4
Västra Götaland	2.4	150.0	1.6
Mean	3.5	118.5	3.1

MI: manifestation index; NS1: non-structural protein 1; TBE: tick-borne encephalitis; TBEV: tick-borne encephalitis virus; WV: whole virus.

^a Annual notifications per 100,000 inhabitants 2004–2018. Data source: Public Health Agency of Sweden (https://www.folkhalsomyndigheten.se/the-public-health-agency-of-sweden/).

^b Infected (WV positive and NS1 positive) per 100,000 inhabitants and year; estimated duration of TBEV NS1 IgG: 20 years.