Three-hundred and fifty-seven fingertip samples were collected from 128 women over a mean of 8.7 months (SD, 5.4 months) follow-up. Twenty-two (6.2%) samples were insufficient for testing, leaving 335 samples from 127 women for analysis (mean 2.6 [SD, 1.2, range 1–5] samples per woman). The mean age at sampling was 18.9 years (SD, 0.8 years). Fourteen samples (4.2%) were collected from women reporting no history of vaginal intercourse.
All 14 samples collected from virgin women tested negative for HPV. Forty-six of 321 fingertip samples (14.3%) collected from sexually active women tested positive for HPV (any type). The mean number of types detected in samples testing positive was 2.1 (SD, 1.6, range 1–7). The most prevalent types detected in fingertip samples were HPV-84 (4.5% positivity) and HPV-16 (3.3% positivity) ( and ).
Figure 1 High-risk type-specific HPV DNA prevalence in 335 fingertip samples collected from 127 women. Types 58, 68, 73, and is39 were not detected in fingertip samples. HPV-68 was detected in 0.6% of concurrently tested genital samples and HPV-73 was detected (more ...)
Figure 2 Low- or undermined-risk type-specific HPV DNA prevalence in 335 fingertip samples collected from 127 women. Types 55, 57, 64, 67, 69, 70, 71, and 72 were not detected in fingertip samples. HPV-55 was detected in 1.2% of concurrently tested genital samples, (more ...)
HPV (any type) was detected in 38.5% (129/335) of genital samples collected at the same visit as a fingertip sample. 20.1% of type-specific HPV detected in the genitals (58/288 types) was detected in the concurrent fingertip sample. Conversely, 60.4% of type-specific HPV detected in the fingertips (58/96 types) was detected in the concurrent genital sample. Pooling across HPV types, the type-specific PPA for detecting HPV between fingertip/genital samples was 17.8% (kappa+=0.17, 95% CI:0.10–0.25).
Forty-one paired type-specific concordant fingertip/genital samples were selected for variant characterization, of which 13 tested negative by PCR-based DNA sequencing in either the fingertip sample (10) or both samples (3). In the remaining 28 pairs, all but one displayed the same variant(s) in each pair (including one pair with two different HPV-16 variants in both samples). The exception had HPV-84 prototype found in the fingertip sample and the variant (with changes of C-to-T at position 19, C-to-T at positive 66, C-to-T at position 171, and T-to-C at position 346) in the genital sample.
If a given HPV type was detected simultaneously in both clinician-collected samples, that type was more likely to be detected in the concurrent fingertip sample than if it were detected in only the cervical or only the vulvar/vaginal sample (OR=6.21, 95%CI:2.32–16.58). HPV types of low or undetermined risk detected in the genitals were borderline statistically significantly more likely to be detected in the concurrent fingertip sample than HPV types of high- or probable high-risk (OR=1.85, 95%CI:0.95–3.60).
Of 109 incident type-specific genital HPV infections with corresponding fingertip samples, 20 (18.3%) were concurrently positive for the same type in the fingertip sample. Of 89 infections with corresponding negative fingertip results, 53 were followed by ≥1 more visit with fingertip sampling (range 1–3 more visits). The same HPV type was detected in a subsequent fingertip sample in 13 cases (24.5%), and all had a corresponding genital sample that was still positive for the same type. The one-year cumulative prevalence of detecting the same HPV type in a concurrent or subsequent fingertip sample was 46.1% (95%CI:33.6–60.7).
On a per-woman level, 29.1% of women (37/127) had HPV detected in ≥1 samples collected from the fingertips. Fifty-five (of 82) type-specific positives were first detected before the last follow-up visit. Of these, eight (14.5%) were re-detected at the next follow-up visit. Thirty of the 55 type-specific positives had a corresponding genital positive. Re-detection was more common in corresponding genital samples; 73.3% (22/30) of types detected in ≥1 genital sites were re-detected at ≥1 genital sites at the next follow-up visit (p<.001). (The likelihood of re-detection did not differ by genital site [73.3% in the vulva/vagina versus 71.4% in the cervix].) When type-specific HPV was detected in both the fingertips and genitals, there were no cases where type-specific HPV was re-detected in the fingertip sample but not in a corresponding genital sample.