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Table 1 Methods used to evaluate the VE against persistent infections and analyses from included studies

From: Measuring vaccine effectiveness against persistent HPV infections: a comparison of different statistical approaches

Type of study Definition of persistence Duration of persistent infection VE analysis method Calculation of infection rates
- Observational [13, 14]
- Experimental [13, 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, 42,43,44,45,46]
- 2 consecutive measurements positive [13, 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, 42,43,44,45,46].
- 2 consecutive measurements: positive preceded by a negative measurement [14]
- Sequence of positive measurements over a certain time span [18, 41]
- 6 monthsa [17, 20, 22, 25, 26, 28,29,30, 34,35,36,37,38,39, 43, 44, 46]
- 12 monthsa [13, 14, 27, 40]
- 6/12 monthsa [16, 18, 19, 21, 23, 24, 31,32,33, 41, 42, 45]
- Conditional exact for comparing two independent Poisson rates using a binomial distribution (14,15,24–28 [39, 41–43] ,16, 35–44,17–23)
- GEE Poisson [13, 40]
- Cox Proportional Hazard [22, 38]
- Prentice Williams Peterson total time approach [14]
- Number of cases/number of participants [17,18,19, 21, 22, 25, 27, 31,32,33, 38, 41,42,43,44]
- Number of cases/person years at risk [13, 14, 16, 20, 23, 24, 26, 28,29,30, 34,35,36,37, 39, 40, 45, 46]
  1. * Although it was stated as 6- or 12-month persistent infections authors specified durations varying between at least 4 to 6 months or 10 to 12 months respectively