Table 3. Sensitivity analyses of country-specific estimates and pooled estimates of historical smallpox vaccine effectiveness against mpox in Denmark, the Netherlands, France and Spain, March–July 2022.

Country	Denmark	France	The Netherlands	Spain
Total number of cases	5	140	113	258
Cases with known vaccination status	5	74	97	131
Proportion of the population vaccinated	95%	90%	89%	90%
Missing values as non-vaccinated
Proportion of cases vaccinated	100%	39%	71%	30%
VE (95% CI)	NA (NA–100)	93% (90–95)	70% (54–80)	95% (94–96)
Pooled VE	90% (58–98)
Missing values as vaccinated
Proportion of cases vaccinated	100%	86%	85%	79%
VE (95% CI)	NA (NA–100)	33% (-10 to 57)	30% (-21 to 57)	57% (42–68)
Pooled VE	46% (18–65)

CI: confidence interval; NA: not ascertainable; VE: vaccine effectiveness.