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Background. Persistent human papillomavirus (HPV) infection is the most important risk factor for cervical cancer, and understanding genotype-specific HPV persistence is essential for elucidating the natural history of HPV infections. Methods. In the Finnish Family HPV Study, 329 pregnant women (mean age, 25.5 years) were recruited during the third trimester of pregnancy and were followed up for 6 years. Multiplex HPV genotyping for 27 low- and high-risk HPV types was used to define genotype-specific prevalence at each visit. Generalized estimating equation models were constructed to estimate predictors of type-specific persistence (positive results at 2 consecutive visits) of species 7 and 9 HPV genotypes. Results. HPV16 was the most common type, followed by HPV types 18, 31, 35, 45, 58, 70, and 6. Prevalence of multiple infections ranged from 21% to 45%. Persistence was most prolonged for HPV types 35, 58, and 52, with durations of 38.7, 32.1, and 24.2 months, respectively, and was equal for multiple-type infections and HPV16, with durations of 21 and 24 months, respectively. Independent predictors of type-specific persistence of species 7 and 9 HPV genotypes were age (odds ratio, 1.13 [95% confidence interval, 1.02-1.25]; [Formula: see text]), oral sex (odds ratio, 0.37 [95% confidence interval, 0.17-0.81]; [Formula: see text]), and young age (<13 years) at initiation of smoking (odds ratio, 0.51 [95% confidence interval, 0.27-0.98]; [Formula: see text]). Conclusion. HPV16 was the most frequent persisting HPV genotype followed by multiple infections. Early initiation of smoking, practicing oral sex and older age increase the risk for persistence of species 7 and 9 HPV genotypes. [ABSTRACT FROM AUTHOR]

We identified the novel HLA‐G*01:21N null allele in Finnish Caucasian individuals. [ABSTRACT FROM AUTHOR]

Abstract Background The knowledge on type specificity and factors that increase or decrease the risk of incident HPV-infections is important to better understand the dynamics of HPV-infections. Methods A series of 329 pregnant women were enrolled in Finnish Family HPV Study at 3rd trimester of pregnancy and followed-up for 6 years, during which 203 baseline HPV-negative women acquired incident HPV infection. Incidence times and incidence rates (IR) were calculated for 24 low-and high-risk HPV-types detected by Multiplex-HPV-genotyping at each visit. Poison regression was used to estimate predictors of incident HPV infections of species 7 and 9 HPV-genotypes. Results HPV16 was the most frequent (47.8%) incident genotype followed by multiple-type infections (25.1%), and single infection with HPV18, 70, 6 and 45. Actuarial mean times to incident event were longest for HPV31 (34.5 months) and HPV45 (32.8 months), while crude mean times were longest for HPV56 (42.4 months) and HPV16 (23.1 months). Actuarial IR was highest for HPV16 and multiple-type infections. Independent protective factors against incident infections were 1) > 2 life-time sexual partners (p = 0.014), 2) later initiation of oral contraceptives (age > 20 years) (p = 0.017) and 3) pregnancy at FU visit (p = 0.0001). Conclusions Among newly delivered mothers, higher number of life-time sexual partners, initiation of OC use after age 20 and becoming pregnant during FU decreased the risk for incident species 7/9 HPV infections.