Results from the SARS-CoV-2 wastewater-based surveillance system in Denmark, July 2021 to June 2022.

The microbiological analysis of wastewater samples is increasingly used for the surveillance of SARS-CoV-2 globally. We described the setup process of the national SARS-CoV-2 wastewater-based surveillance system in Denmark, presented its main results during the first year of activities, from July 2021 to June 2022, and discussed their operational significance. The Danish SARS-CoV-2 wastewater-based surveillance system was designed to cover 85 % of the population in Denmark and it entailed taking three weekly samples from 230 sites. Samples were RT-qPCR tested for SARS-CoV-2 RNA, targeting the genetic markers N1, N2 and RdRp, and for two faecal indicators, Pepper Mild Mottle Virus and crAssphage. We calculated the weekly SARS-CoV-2 RNA concentration in the wastewater from each sampling site and monitored it in view of the results from individual testing, at the national and regional levels. We attempted to use wastewater results to identify potential local outbreaks, and we sequenced positive wastewater samples using Nanopore sequencing to monitor the circulation of viral variants in Denmark. The system reached its full implementation by October 2021 and covered up to 86.4 % of the Danish population. The system allowed for monitoring of the national and regional trends of SARS-CoV-2 infections in Denmark. However, the system contribution to the identification of potential local outbreaks was limited by the extensive information available from clinical testing. The sequencing of wastewater samples identified relevant variants of concern, in line with results from sequencing of human samples. Amidst the COVID-19 pandemic, Denmark implemented a nationwide SARS-CoV-2 wastewater-based surveillance system that integrated routine surveillance from individual testing. Today, while testing for COVID-19 at the community level has been discontinued, the system is on the frontline to monitor the occurrence and spread of SARS-CoV-2 in Denmark.

Papilloplex HR-HPV test has non-inferior clinical performance for detection of human papillomavirus infection: assessment using the VALGENT framework.

AIM: The Papilloplex high-risk human papillomavirus (hrHPV) test (Genefirst, Oxford, UK) is a single tube real-time HPV test which provides multiplex detection and separate identification of 14 hrHPV types. Here, we present the clinical validation of the test in SurePath samples in comparison to a clinically validated reference test, the GP5+/6+Enzyme ImmunoAssay (GP5+/6+EIA) using the VALGENT (VALidation of HPV GENotyping Tests) framework. METHODS: Clinical performance was assessed using 998 unselected, cervical screening samples enriched with 297 cytologically abnormal specimens (100 atypical squamous cells of unspecified significance, 100 low-grade squamous intraepithelial lesions, 97 high-grade squamous intraepithelial lesions). Cases were defined as women diagnosed with histologically confirmed cervical intraepithelial neoplasia two or more (≥CIN2, N=119) and controls defined as women with two subsequent negative cytology results (N=834). RESULTS: The Papilloplex HR-HPV test has non-inferior sensitivity for detection of cervical precancer (p=0.0001 for ≥CIN2 and p=0.0005 for ≥CIN3) and non-inferior specificity, compared with GP5+/6+EIA (pni=0.0167)). The assay also showed excellent or good agreement for overall hrHPV and nearly all individual HPV types as compared with GP5+/6+EIA/Luminex. CONCLUSION: The Papilloplex HR-HPV applied on cervical specimens stored in SurePath medium fulfils the international clinical accuracy criteria for use in cervical cancer screening.

Operational experiences from the general implementation of HPV self-sampling to Danish screening non-attenders.

The Danish cervical cancer screening program is a cost-free cancer prevention program for all Danish resident women aged 23-64 years. The coverage is 73%, but screening attendance is slowly declining. Notwithstanding, almost half of all newly diagnosed cervical cancers are found amongst screening non-attenders. To increase screening attendance, the Capital Region of Denmark implemented HPV self-sampling as an alternative offer to women not attending the regular screening offer. This was an opt-in offer to 57,717 screening non-attending women in 2017-2018. They received an invitation letter and could opt-in by letter, phone, e-mail, or website. Invitation and return-of-kit reminders were used in the set-up. HPV positive women were recommended to go to their General Practitioner (GP) for a follow-up sample. HPV negative women returned to the ordinary screening program. Of all invited women, 15,501 opted-in (27%). The purpose designed website was the most frequent used method of response, 63% opted in by the HPV-self sampling website. Use of invitation and return-of-kit reminders generated 8.6% and 6.1% additional responses and participation, respectively, underlining the importance of timely communication. Overall, 17% returned the HPV self-sampling kit for analysis. In addition, 14% had a regular clinician collected screening sample after receiving the invitation for self-sampling, leading to a total screening of 31% of the invited women. HPV prevalence was 15% and 92% of the women positive for HPV adhered to the recommended follow-up.

Clinical Validation of the Onclarity Assay After Assay Migration to the High-Throughput COR Instrument Using SurePath Screening Samples From the Danish Cervical Cancer Screening Program.

OBJECTIVES: This study presents the clinical assessment of the Onclarity HPV Assay (Becton Dickinson) on the novel COR high-throughput instrument (Becton Dickinson) using the international guidelines in a routine setting. METHODS: Screening samples collected in BD SurePath from women aged 30 years and older were used in this validation. Noninferiority of the Onclarity HPV Assay on the COR instrument (Onclarity-COR) was assessed with the comparator assay glycoprotein 5-positive (GP5+)/6+ enzyme immunoassay (GP-EIA) for clinical sensitivity on 122 cervical intraepithelial neoplasia 2 and greater samples. Specificity was assessed using 887 samples with twice-normal cytology. Inter- and intralaboratory reproducibility analysis was assessed using 525 samples. Finally, a time-and-motion study was performed to evaluate COR instrument performance characteristics. RESULTS: The Onclarity-COR was noninferior to the GP-EIA for both sensitivity (P = .0016) and specificity (P < .0001). The intralaboratory reproducibility was 98.3% (κ = 0.96), and interlaboratory agreement was 98.5 % (κ = 0.96). The daily hands-on time for the COR instrument was 58 minutes, and walk-away time was 7 hours, 2 minutes per 8-hour day shift. CONCLUSIONS: The Onclarity-COR instrument fulfills international validation criteria on sensitivity, specificity, and laboratory reproducibility. The Onclarity assay's extended genotyping capability, together with its high-throughput characteristics, makes the COR instrument an excellent candidate for use in human papillomavirus primary cervical cancer screening.

Evaluation of HarmoniaHPV test for detection of clinically significant Human Papillomavirus infection using the VALGENT framework.

AIM: The VALidation of HPV GENotyping Tests (VALGENT) is a framework for comparison and validation of HPV tests with genotyping capabilities. In this study, the clinical performance of a single tube HPV test -HarmoniaHPV- was assessed in SurePath™ samples and compared to a clinically validated reference test, the GP5+/6+ Enzyme ImmunoAssay (GP5+/6 + EIA). METHODS: HarmoniaHPV test is a real-time, PCR based, limited genotyping HPV test which detects 14 high-risk HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68 with HPV16, and HPV 18 reported individually. Clinical performance was assessed using 998 unselected, cervical screening samples enriched with 297 cytologically abnormal specimens (100 atypical squamous cells of unspecified significance, 100 low-grade squamous intraepithelial lesions, 97 high-grade squamous intraepithelial lesions). Cases were defined as women diagnosed with histologically confirmed cervical intraepithelial neoplasia 2 or more (≥CIN2, N = 122). RESULTS: Using the manufacturer recommended (un-adjusted) cut-offs, HarmoniaHPV had non-inferior sensitivity for detection of ≥ CIN2 but showed inferior specificity. A cut-off optimisation exercise was therefore carried out and optimised cut-offs for each individual channel rendered a sensitivity and specificity of HarmoniaHPV that was non-inferior to GP5+/6 + EIA. Analytically, the test showed excellent intra- and inter-laboratory reproducibility, which improved further with the use of the optimised cut-offs. CONCLUSION: HarmoniaHPV when operated with optimised cut-offs fulfils the international clinical criteria for use in cervical cancer screening on SurePath samples. The optimised cut-offs warrant additional testing and independent validation.

Clinical and analytical performance of the CLART HPV 4S assay with SurePath screening samples from the Danish cervical cancer screening program using the VALGENT framework.

The CLART HPV4S (CLART4S) is a novel full genotyping assay, based on PCR/microarray technology. We assessed the clinical accuracy of the CLART4S assays under the fourth installment of the VALGENT framework. The VALGENT cohort comprised 998 consecutive cervical samples from women participating in the Danish screening programme enriched with 297 samples with abnormal cytology (100 ASCUS, 100 LSIL, 97 HSIL). The CLART4S assay detects 16 HPV genotypes individually: 14 oncogenic and two non-oncogenic HPV types. The GP5+/6+ PCR Enzyme-Immuno-Assay (GP-EIA) and GP5+/6+ PCR with Luminex genotyping (GP-LMNX) were used as comparator tests for clinical accuracy and HPV genotype concordance, respectively. The sensitivity for ≥ CIN2 for the CLART4S assay was 96.7 % (GP-EIA: 92.6 %) with a relative sensitivity of 1.04 (1.00-1.09). The sensitivity for ≥ CIN3 was 98.8 % (GP-EIA: 94.0 %), with relative sensitivity of 1.05 (1.00-1.10). The specificity for

Clinical validation of full genotyping CLART® HPV4S assay on SurePath and ThinPrep collected screening samples according to the international guidelines for human papillomavirus test requirements for cervical screening.

BACKGROUND: To ensure the highest quality of human papillomavirus (HPV) testing in primary cervical cancer screening, novel HPV assays must be evaluated in accordance with the international guidelines. Furthermore, HPV assay with genotyping capabilities are becoming increasingly important in triage of HPV positive women in primary HPV screening. Here we evaluate a full genotyping HPV assay intended for primary screening. METHODS: The CLART® HPV4S (CLART4S) assay is a newly developed full-genotyping assay detecting 14 oncogenic (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68) and two non-oncogenic HPV genotypes (6, 11). It was evaluated using SurePath and ThinPrep screening samples collected from the Danish and Swedish cervical cancer screening programs, respectively. For calculation of sensitivity, 81 SurePath and 80 ThinPrep samples with confirmed ≥CIN2 were assessed. For clinical specificity analysis, 1184 SurePath and 1169 ThinPrep samples from women with

Clinical validation of the Cobas 4800 HPV assay using cervical samples in SurePath medium under the VALGENT4 framework.

BACKGROUND: The VALidation of HPV Genotyping Tests (VALGENT) framework is an international cooperation designed for comparison and clinical validation of HPV assays with genotyping capabilities. OBJECTIVES: Here we addressed the accuracy of the Roche cobas 4800 HPV test using SurePath samples from the Danish cervical cancer screening program under the VALGENT framework. MATERIAL AND METHODS: The VALGENT4 panel comprises 998 consecutive SurePath cervical samples from routine screening and 297 SurePath samples enriched for disease (100 ASC-US, 100 LSIL, 97 HSIL). The cobas HPV test is a real-time PCR assay which detects HPV16 and 18 individually and 12 other high-risk (hr) HPV genotypes in one bulk. RESULTS: The clinical performance of the cobas test was assessed relative to that of the comparator assay GP5+/6 + PCR Enzyme ImmunoAssay (GP-EIA) by a non-inferiority test. The relative sensitivity for ≥ CIN2 was 1.00 (95% CI: 0.97-1.04) and relative specificity for the control group was 1.02 (95% CI: 1.01-1.04). The cobas test was found non-inferior to that of GP-EIA for both sensitivity and specificity (p-0.0006 and p < 0.0001, respectively). The type specific performance of the cobas test was evaluated using the GP5+/6 + PCR with Luminex genotyping (GP-LMNX) as comparator. The cobas test showed excellent to good concordance (Kappa: 0.70 to 0.90) with GP-LMNX for all three genotype groups in the overall VALGENT population but good to moderate concordance in the Screening population (kappa from 0.56 to 0.80). CONCLUSIONS: The cobas HPV test demonstrated non-inferiority to the comparator assay on cervical SurePath screening samples using the VALGENT4 panel.

Clinical and Analytical Performance of the BD Onclarity HPV Assay with SurePath Screening Samples from the Danish Cervical Screening Program Using the VALGENT Framework.

The Validation of HPV Genotyping Tests (VALGENT) framework is an international cooperation designed to evaluate human papillomavirus (HPV) assays with genotyping capabilities. Here, we assessed the performance of the BD Onclarity assay using Danish SurePath cervical screening samples collected under the fourth VALGENT installment, consisting of 998 consecutive samples from a screening population and 297 enriched samples with abnormal cytology (100 with atypical squamous cells of undetermined significance [ASCUS], 100 with low-grade squamous intraepithelial lesions [LSIL], and 97 with high-grade squamous intraepithelial lesions [HSIL]). The Onclarity assay detects six HPV genotypes individually (genotypes 16, 18, 31, 45, 51, and 52) and eight genotypes in three bulks (genotypes 33 and 58; genotypes 56, 59, and 66; and genotypes 35, 39, and 68). The clinical performance of the Onclarity assay for the detection of cervical intraepithelial neoplasia of grade 2 or worse (≥CIN2) and of two consecutive cytology outcomes negative for intraepithelial lesion or malignancy (2×NILM) was assessed relative to that of the GP5+/6+ PCR-enzyme immunoassay (GP-EIA) by a noninferiority test. The relative sensitivity for ≥CIN2 was 1.00 (95% confidence interval [CI], 0.97 to 1.04), and the relative specificity for 2×NILM was 1.04 (95% CI, 1.02 to 1.06). The Onclarity assay was found to be noninferior to the GP-EIA in terms of both sensitivity (P = 0.0006) and specificity (P < 0.0001). The type-specific performance of the Onclarity assay was also assessed, using the GP5+/6+ PCR with Luminex genotyping (GP-LMNX) as the comparator. The Onclarity assay showed good concordance for almost all HPV genotype groups. A stability analysis of SurePath samples was also performed, where a SurePath aliquot was stored refrigerated for 7 months and the internal control of the Onclarity assay was used as a marker for cellularity. The threshold cycle (CT ) value was the same (24.8) in the first and second Onclarity runs, showing that a SurePath sample can be stored refrigerated for 7 months and still remain a valid test specimen.

The Valgent4 protocol: Robust analytical and clinical validation of 11 HPV assays with genotyping on cervical samples collected in SurePath medium.

BACKGROUND: The VALidation of HPV GENoyping Tests (VALGENT) is an international initiative designed to validate HPV assays with genotyping capability. The VALGENT4 protocol differs from previous VALGENT installments as the sample collection medium is SurePath, and exclusively includes samples from women ≥30 years of age which is concordant with the majority of HPV primary screening guidelines. Here we present the protocol for the fourth installment of the VALGENT framework. OBJECTIVES: In VALGENT4 11 HPV assays will be evaluated using two comparator assays based on PCR with the GP5+/6+ primers. STUDY DESIGN: Overall, the VALGENT4 panel consists of 1,297 routine samples comprised of 998 unselected, consecutive samples, of which 51 samples had abnormal cytology with 13 women diagnosed with ≥CIN2, and 299 consecutive samples enriched for ≥ASCUS cytology (100 ASCUS, 100 LSIL, 99 HSIL) with 106 ≥CIN2 upon follow up. Manipulated and DNA extracted panel samples were characterized with respect to human beta globin (HBB) and overall DNA content and composition to quality assess the panel prior to distribution to the collaborating sites. RESULT: The relative cellularity (mean CT value of HBB from the Onclarity assay) on the 1,297 LBC samples (CT=24.8) was compared with 293 un-manipulated routine cytology screening samples (CT=23.8). Furthermore, the DNA extracted panel samples was characterized using the Exome iPLEX pro assay, which reports amplifiable copies on individual samples as well as copies of five different base pair lengths. Here the data showed a slightly lower number of amplifiable DNA copies (ratio: 0.7, p=<0.01)) in the VALGENT4 panel samples compared to routine extracted cervical DNA samples CONCLUSION: The present manuscript details the manipulation, processing and quality assessment of samples used in VALGENT-4. This methodological document may be of value for future international projects of HPV test validation.

Time and temperature dependent analytical stability of dry-collected Evalyn HPV self-sampling brush for cervical cancer screening.

As a new initiative, HPV self-sampling to non-attenders using the dry Evalyn self-sampling brush is offered in the Capital Region of Denmark. The use of a dry brush is largely uncharted territory in terms of analytical stability. In this study we aim to provide evidence on the analytical quality of dry HPV self-sampling brushes as a function of time and temperature. We assessed the analytical stability of dry stored Evalyn brushes at three different temperatures, (4 °C, room temperature, 30 °C) and five different storage time points; T = 0 (baseline), 2, 4, 8, 16, and 32 weeks prior to HPV analysis using the BD Onclarity HPV assay. Mean Ct value of the Onclarity internal control was used as comparator of cellularity across time and temperatures, with no or only borderline statistical differences observed. HPV detection was stable throughout the five time points. In addition, analytically amplifiable DNA copy numbers and DNA fragmentation was assessed using the Agena iPLEX Exome QC assay, with no or only borderline statistical differences observed. In conclusion, the Evalyn brush is analytically stable with respect to human genomic material and HPV detection for up to 32 weeks at temperatures ranging from 4 °C to 30 °C.

Cross-reactivity profiles of hybrid capture II, cobas, and APTIMA human papillomavirus assays: split-sample study.

BACKGROUND: High-risk Human Papillomavirus (HPV) testing is replacing cytology in cervical cancer screening as it is more sensitive for preinvasive cervical lesions. However, the bottleneck of HPV testing is the many false positive test results (positive tests without cervical lesions). Here, we evaluated to what extent these can be explained by cross-reactivity, i.e. positive test results without evidence of high-risk HPV genotypes. The patterns of cross-reactivity have been thoroughly studied for hybrid capture II (HC2) but not yet for newer HPV assays although the manufacturers claimed no or limited frequency of cross-reactivity. In this independent study we evaluated the frequency of cross-reactivity for HC2, cobas, and APTIMA assays. METHODS: Consecutive routine cervical screening samples from 5022 Danish women, including 2859 from women attending primary screening, were tested with the three evaluated DNA and mRNA HPV assays. Genotyping was undertaken using CLART HPV2 assay, individually detecting 35 genotypes. The presence or absence of cervical lesions was determined with histological examinations; women with abnormal cytology were managed as per routine recommendations; those with normal cytology and positive high-risk HPV test results were invited for repeated testing in 18 months. RESULTS: Cross-reactivity to low-risk genotypes was detected in 109 (2.2 %) out of 5022 samples on HC2, 62 (1.2 %) on cobas, and 35 (0.7 %) on APTIMA with only 10 of the samples cross-reacting on all 3 assays. None of the 35 genotypes was detected in 49 (1.0 %), 162 (3.2 %), and 56 (1.1 %) samples, respectively. In primary screening at age 30 to 65 years (n = 2859), samples of 72 (25 %) out of 289 with high-risk infections on HC2 and < CIN2 histology were due to cross-reactivity. On cobas, this was 106 (26 %) out of 415, and on APTIMA 48 (21 %) out of 224. CONCLUSIONS: Despite manufacturer claims, all three assays showed cross-reactivity. In primary cervical screening at age ≥30 years, cross-reactivity accounted for about one quarter of false positive test results regardless of the assay. Cross-reactivity should be addressed in EU tenders, as this primarily technical shortcoming imposes additional costs on the screening programmes.

Clinical and analytical performance of the BD Onclarity™ HPV assay for detection of CIN2+ lesions on SurePath samples.

BACKGROUND: The novel BD OnclarityTM HPV assay (Onclarity) on the BD Viper™ LT system (BD Diagnostics, Sparks, MD), detects E6/E7 DNA from 13 high-risk HPV genotypes and HPV66. We compared the analytical and clinical performance of the Onclarity Assay to that of Hybrid Capture 2 and LINEAR ARRAY using adjudicated histological outcomes from Danish women referred for colposcopy. METHODS: 276 women from Copenhagen, Denmark were referred for colposcopy with abnormal cytology and/or a positive HPV test. Two samples for HPV analysis were taken in BD SurePath™ and in the BD cervical brush diluent (CBD) media. ClinicalTrial gov. identifier: NCT01671462, Ethical Approval: H-4-2012-070. RESULTS: Histology was normal in 84 (31%) women, 70 (26%) had CIN1, 47 (17%) CIN2, and 68 (25%) had CIN3. The Onclarity assay detected 67 out of 68 (99%) ≥CIN3 and 113/115 (98%) ≥CIN2. The specificities for

Comparison of analytical and clinical performance of CLART HPV2 genotyping assay to Linear Array and Hybrid Capture 2: a split-sample study.

BACKGROUND: Human Papillomavirus (HPV) genotyping has an increasingly important role in cervical cancer screening and vaccination monitoring, however, without an internationally agreed standard reference assay. The test results from the most widely used genotyping assays are read manually and hence prone to inter-observer variability. The reading of test results on the CLART HPV2 genotyping assay is, on the other hand, automated. The aim of our study was to directly compare the detection of HPV genotypes and high-grade cervical intraepithelial neoplasia (CIN) by CLART, Linear Array (LA), and Hybrid Capture 2 (HC2) using samples stored in SurePath. METHODS: Residual material from 401 routine samples from women with abnormal cytology was tested by CLART, LA, and HC2 (ClinicalTrial.gov: NCT01671462, Ethical Committee approval: H-2012-070). Histological outcomes were ascertained by linkage to the Danish nation-wide Pathology Data Bank. For comparison of CLART and LA in terms of genotype detection, we calculated κ-coefficients, and proportions of overall and positive agreement. For comparison of CIN detection between CLART, LA, and HC2, we calculated the relative sensitivity and specificity for high-grade CIN. RESULTS: The κ-coefficient for agreement in detection of genotypes 16, 18, 31, 33, 35, and 51 was ≥0.90 (overall agreement: 98-99%, positive agreement: 84-95%). The values were slightly lower, but still in the "substantial" range for genotypes 39, 45, 52, 56, 58, 59, and several low-risk genotypes. The relative sensitivity of CLART for ≥ CIN2 and ≥ CIN3 was not significantly lower than that of LA and HC2, although CLART showed a higher specificity than HC2. CONCLUSIONS: In Danish women with abnormal SurePath cytology, CLART and LA were highly comparable for detection of most high-risk and low-risk genotypes; and CLART's sensitivity for high-grade CIN was comparable to that of both LA and HC2.

HPV prevalence and genotype distribution in a population-based split-sample study of well-screened women using CLART HPV2 human papillomavirus genotype microarray system.

BACKGROUND: Human papillomavirus (HPV) genotyping assays are becoming increasingly attractive for use in mass screening, as they offer a possibility to integrate HPV screening with HPV vaccine monitoring, thereby generating a synergy between the two main modes of cervical cancer prevention. The Genomica CLART HPV2 assay is a semi-automated PCR-based microarray assay detecting 35 high-risk and low-risk HPV genotypes. However, few reports have described this assay in cervical screening. An aim of the present study, Horizon, was to assess the prevalence of high-risk HPV infections in Copenhagen, Denmark, an area with a high background risk of cervical cancer where women aged 23-65 years are targeted for organized screening. METHODS: Material from 5,068 SurePath samples of women participating in routine screening and clinical follow-up of cervical abnormalities was tested using liquid based cytology, CLART HPV2 and Hybrid Capture 2 (HC2). RESULTS: At least one of the 35 defined genotypes was detected by CLART in 1,896 (37%) samples. The most frequent high-risk genotypes were HPV 16 (7%), HPV 52 (5%), and HPV 31 (4%). The most frequent low-risk genotypes were HPV 53 (5%), HPV 61 (4%), and HPV 66 (3%). Among 4,793 women targeted by the screening program (23-65 years), 1,166 (24%) tested positive for one or more of the 13 high-risk genotypes. This proportion decreased from 40% at age 23-29 years to 10% at age 60-65 years. On HC2, 1,035 (20%) samples were positive for any high-risk and thus CLART showed a higher analytical sensitivity for 13 high-risk HPV genotypes than HC2, and this was found in all age-groups and in women normal cytology. CONCLUSIONS: CLART performed well with a positive reproducibility for high-risk genotypes of 86%, and a negative reproducibility of 97%. This report furthermore updates the genotype distribution in Denmark prior to the inclusion of the HPV-vaccinated cohorts into the screening program, and as such represents a valuable baseline for future vaccine impact assessment.

Disagreement between human papillomavirus assays: an unexpected challenge for the choice of an assay in primary cervical screening.

We aimed to determine the disagreement in primary cervical screening between four human papillomavirus assays: Hybrid Capture 2, cobas, CLART, and APTIMA. Material from 5,064 SurePath samples of women participating in routine cervical screening in Copenhagen, Denmark, was tested with the four assays. Positive agreement between the assays was measured as the conditional probability that the results of all compared assays were positive given that at least one assay returned a positive result. Of all 5,064 samples, 1,679 (33.2%) tested positive on at least one of the assays. Among these, 41% tested positive on all four. Agreement was lower in women aged ≥ 30 years (30%, vs. 49% at <30 years), in primary screening samples (29%, vs. 38% in follow-up samples), and in women with concurrent normal cytology (22%, vs. 68% with abnormal cytology). Among primary screening samples from women aged 30-65 years (n = 2,881), 23% tested positive on at least one assay, and 42 to 58% of these showed positive agreement on any compared pair of the assays. While 4% of primary screening samples showed abnormal cytology, 6 to 10% were discordant on any pair of assays. A literature review corroborated our findings of considerable disagreement between human papillomavirus assays. This suggested that the extent of disagreement in primary screening is neither population- nor storage media-specific, leaving assay design differences as the most probable cause. The substantially different selection of women testing positive on the various human papillomavirus assays represents an unexpected challenge for the choice of an assay in primary cervical screening, and for follow up of in particular HPV positive/cytology normal women.

Prevalence of human papillomavirus in 5,072 consecutive cervical SurePath samples evaluated with the Roche cobas HPV real-time PCR assay.

New commercially available Human Papillomavirus (HPV) assays need to be evaluated in a variety of cervical screening settings. Cobas HPV Test (cobas) is a real-time PCR-based assay allowing for separate detection of HPV genotypes 16 and 18 and a bulk of 12 other high-risk genotypes. The aim of the present study, Horizon, was to assess the prevalence of high-risk HPV infections in an area with a high background risk of cervical cancer, where women aged 23-65 years are targeted for cervical screening. We collected 6,258 consecutive cervical samples from the largest cervical screening laboratory in Denmark serving the whole of Copenhagen. All samples were stored in SurePath media. In total, 5,072 samples were tested with cobas, Hybrid Capture 2 High Risk HPV DNA test (HC2) and liquid-based cytology. Of these, 27% tested positive on cobas. This proportion decreased by age, being 43% in women aged 23-29 years and 10% in women aged 60-65 years. HC2 assay was positive in 20% of samples, and cytology was abnormal (≥ atypical squamous cells of undetermined significance) for 7% samples. When only samples without recent abnormalities were taken into account, 24% tested positive on cobas, 19% on HC2, and 5% had abnormal cytology. The proportion of positive cobas samples was higher than in the ATHENA trial. The age-standardized cobas positivity vs. cytology abnormality was 3.9 in our study and 1.7 in ATHENA. If in Copenhagen the presently used cytology would be replaced by cobas in women above age 30 years, an extra 11% of women would based on historical data be expected to have a positive cobas test without an underlying cervical intraepithelial lesion grade 3 or worse. Countries with a high prevalence of HPV infections should therefore proceed to primary HPV-based cervical screening with caution.

Patterns of cervical coinfection with multiple human papilloma virus types in a screening population in Denmark.

Patterns of cervical human papillomavirus (HPV) infection suggest that HPV genotypes are not independent of each other. This may be explained by risk factors common to all HPV infections, but type-specific biological factors may also play a role. This raises the question of whether widespread use of the quadrivalent vaccine (covering HPV6, 11, 16, 18) may indirectly affect the prevalence of any non-vaccine types. Routine screening samples from 5014 Danish women were tested for 35 HPV genotypes (including 13 high-risk) using the Genomica CLART(®) HPV2 kit, which is a low-density microarray based on PCR amplification. Simulation studies were performed both under independence between genotypes and under a common dependence structure as would arise from common risk factors, and simulation results were compared to observed coinfection patterns. Overall HPV prevalence was 37.4%, with multiple infections in 17.9%. For 15 HPV types of primary interest (13 high-risk plus HPV6, 11), almost all pairs occurred more often than expected under independence; 33/105 (31.4%) were statistically significant (p<0.05 after adjustment for multiple comparisons). The pairwise odds ratios showed significant heterogeneity (Woolf's test p<0.0001). For simulations based on common dependence, three pairs had observed to expected (O/E) ratios significantly different than 1 (31/68, O/E=4.20; 51/68, O/E=2.52; 33/58, O/E=3.27; all p<0.05 after adjustment for multiple comparisons). HPV68 occurred in multiple infections nearly four times as often as expected under common dependence (p<0.005 after adjustment for multiple comparisons). These results indicate some interaction between HPV types, and suggest that common risk factors do not entirely explain the observed HPV coinfection pattern, although no evidence is found that the prevalence of any types not targeted by the quadrivalent vaccine may be indirectly increased or decreased after widespread use of the vaccine.