High coverage and adherence to dose intervals of the national school-based HPV vaccination program in Sweden during 2012-2019.

Background: Close monitoring of vaccination coverage is important for cervical cancer prevention efforts. The study aims to describe the HPV vaccination coverage by dose in girls eligible for HPV vaccination within Sweden's childhood immunization program and provide an estimate on dose timing compliance. Methods: Vaccination records between 2012 and March 2019 were obtained for girls born in 2000-2006 from the vaccination registers in Sweden. The mid-time population counts for the respective birth cohorts were taken as the denominator. Full-dose coverage and coverage with at least one dose of the vaccine were calculated within the two-dose and three-dose regimen, by region. Dose compliance was calculated within the two-dose regimen. Results: Vaccination coverage with at least one dose of the vaccine was >80% within birth cohorts 2001-2006. Full-dose coverage within a two-dose and three-dose regimen were 73.4% in birth cohorts 2004-2005, and 56.3% in birth cohorts 2000-2001, respectively. Little variation was observed in vaccination coverage between regions. Dose completion was 91.8%, and 72.8% in girls that initiated a two-dose and three-dose regimen, respectively. Among girls receiving a two-dose regimen, 93.0% received the second dose 6-12 months after dose one. Discussion: In conclusion, high levels of HPV vaccination coverage were observed with little variation between regions. Dose timing compliance was particularly high in the two-dose regimen. To fully benefit from the impact of HPV vaccination, it will be important to further push the vaccination coverage and reach the girls that do not or partially engage with HPV vaccination.

Evaluation of co-testing with cytology and human papillomavirus testing in cervical screening.

Cervical screening is increasingly switching to human papillomavirus (HPV) testing. In many settings, the switch has involved one or several co-tests (testing using both cytology and HPV) in the screening guidelines, to ensure safety. When Sweden switched to HPV testing in 2015 the guidelines included a co-test at age 41. To evaluate the effect of co-testing, we identified all 208,701 women resident in Sweden who in 2019 were 40-42 years old and thus eligible for co-testing. All cervical samples, the results of the test and of the subsequent biopsies were identified in the Swedish National Cervical Screening Registry. Out of the 10,643 women with co-testing in screening, there were 197 women with a subsequent biopsy with high-grade cervical neoplasia or worse (CIN2+). Among these 197 women, 189 had a screening test positive for both HPV and cytology, 6 women were HPV+/Cyt- and 2 women were HPV-/Cyt+. There were 7115 women with a co-test outside of the screening program. Among these, 325 women had a CIN2+ in histopathology, 290 were double positive, 13 women were cyt+/HPV-, and 11 women each were HPV+/cyt- and HPV-/Cyt-. In summary, the additional yield of CIN2+ with co-testing was 2 cases per 10,643 women as compared with 195/10,643 CIN2+ cases detected with HPV screening alone. However, for cervical samples taken outside the screening program (e.g. taken on a clinical indication) there was an increased yield (314 CIN2+ cases detected with co-testing as compared to 301 cases with HPV screening).

Human Papillomavirus Infection Determines Prognosis in Cervical Cancer.

PURPOSE: Detection of human papillomavirus (HPV) by polymerase chain reaction in invasive cervical cancer is strongly associated with prognosis but previous studies have not considered sequencing efforts. We aimed to assess the association when also including comprehensive analysis of HPV infection by deep sequencing and a longer follow-up period. MATERIALS AND METHODS: We subjected all 392 of 2,845 invasive cervical cancer cases that were polymerase chain reaction-negative for HPV to RNA sequencing on the NovaSeq 6000 platform (Illumina) and identified an additional 169 cases as HPV-positive. We followed all women from date of diagnosis to December 31, 2016, emigration, or death, whichever occurred first. The main outcome was all-cause mortality by December 31, 2016. We calculated 5-year cumulative relative survival ratios compared with the female general population and used Poisson regression to estimate excess hazard ratios of all-cause mortality by infection with any of the 13 most oncogenic (high-risk [hr]) HPV types in the tumor. All models were adjusted for age, time since diagnosis, stage, histology, and education level. RESULTS: The 5-year cumulative relative survival ratio was 0.45 (95% CI, 0.39 to 0.51) in the hrHPV-negative group, and 0.74 (95% CI, 0.72 to 0.75) in the hrHPV-positive group. This translated to a statistically significantly 43% lower excess mortality in the hrHPV-positive group compared with the hrHPV-negative (corresponding to an excess hazard ratio 0.57; 95% CI, 0.48 to 0.69). There was no association between HPV risk group, clade, or number of HPV infections and prognosis. CONCLUSION: hrHPV status is a strong determinant of cervical cancer prognosis over 15 years after diagnosis, above and beyond other established factors.

Nonvaccine human papillomavirus genotype common in women with HIV failing cervical precancer treatment.

OBJECTIVE: The aim of this study was to assess failure after treatment of high-grade cervical intraepithelial neoplasia (CIN2+) by HIV status and human papillomavirus (HPV) type. DESIGN: A population-based register study. METHODS: The Swedish National HIV Registry, the Swedish Population Registry and the Swedish National Cervical Screening Registry were linked to identify all women in Stockholm and Gothenburg counties (Sweden) living with HIV and diagnosed with CIN2+ sometime between 1983 and 2014 (n = 179). HIV-negative controls with CIN2+, were matched (2 : 1) for country of birth. CIN2+ biopsies were retrieved from biobanks and genotyped. Absolute risk and adjusted odds ratios (adjOR) of treatment failure by HIV status given HPV type (HPV16/18 vs. non-HPV16/18) were calculated. RESULTS: HPV16 (32%) and HPV35 (24%) dominated in women living with HIV (WLWH) with failure, HPV35 mainly in women born in sub-Saharan Africa (67%). The absolute risk of failure in women with HPV16/18 was 26% [95% confidence interval (95% CI) 14-44] in WLWH and 12% in HIV-negative (95% CI 7-19). The absolute risk of failure in women with non-HPV16/18 was 20% (95% CI 12-31) in WLWH and 5% in HIV-negative (95% CI 2-11). WLWH with non-HPV16/18 were six times more likely to fail than HIV-negative (adjOR 6.1, 95% CI 2.0-18.6). CONCLUSION: HPV35, not included in current HPV vaccines, was the second most common type in WLWH with failure. WLWH with non-HPV16/18 were six times more likely to fail than HIV-negative. This could have implications for surveillance and vaccination post CIN2+ treatment, particularly in WLWH from sub-Saharan Africa.

Antibodies to SARS-CoV-2 and risk of past or future sick leave.

The extent that antibodies to SARS-CoV-2 may protect against future virus-associated disease is unknown. We invited all employees (n = 15,300) at work at the Karolinska University Hospital, Stockholm, Sweden to participate in a study examining SARS-Cov-2 antibodies in relation to registered sick leave. For consenting 12,928 healthy hospital employees antibodies to SARS-CoV-2 could be determined and compared to participant sick leave records. Subjects with viral serum antibodies were not at excess risk for future sick leave (adjusted odds ratio (OR) controlling for age and sex: 0.85 [95% confidence interval (CI) (0.85 (0.43-1.68)]. By contrast, subjects with antibodies had an excess risk for sick leave in the weeks prior to testing [adjusted OR in multivariate analysis: 3.34 (2.98-3.74)]. Thus, presence of viral antibodies marks past disease and protection against excess risk of future disease. Knowledge of whether exposed subjects have had disease in the past or are at risk for future disease is essential for planning of control measures.Trial registration: First registered on 02/06/20, ClinicalTrials.gov NCT04411576.

High Amounts of SARS-CoV-2 Precede Sickness Among Asymptomatic Health Care Workers.

BACKGROUND: Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity among asymptomatic subjects reflects past or future disease may be difficult to ascertain. METHODS: We tested 9449 employees at Karolinska University Hospital, Stockholm, Sweden for SARS-CoV-2 RNA and antibodies, linked the results to sick leave records, and determined associations with past or future sick leave using multinomial logistic regression. RESULTS: Subjects with high amounts of SARS-CoV-2 virus, indicated by polymerase chain reaction (PCR) cycle threshold (Ct) value, had the highest risk for sick leave in the 2 weeks after testing (odds ratio [OR], 11.97; 95% confidence interval [CI], 6.29-22.80) whereas subjects with low amounts of virus had the highest risk for sick leave in the 3 weeks before testing (OR, 6.31; 95% CI, 4.38-9.08). Only 2.5% of employees were SARS-CoV-2 positive while 10.5% were positive by serology and 1.2% were positive in both tests. Serology-positive subjects were not at excess risk for future sick leave (OR, 1.06; 95% CI, .71-1.57). CONCLUSIONS: High amounts of SARS-CoV-2 virus, as determined using PCR Ct values, was associated with development of sickness in the next few weeks. Results support the concept that PCR Ct may be informative when testing for SARS-CoV-2. Clinical Trials Registration. NCT04411576.

Deep sequencing detects human papillomavirus (HPV) in cervical cancers negative for HPV by PCR.

BACKGROUND: Human papillomavirus (HPV) is a necessary cause of cervical cancer, although some invasive cervical cancers may test negative by HPV PCR. We previously requested all invasive cervical cancers in Sweden during 10 years and subjected them to PCR. We also optimised methods for deep sequencing of formalin-fixed paraffin-embedded samples. METHODS: Using Novaseq 6000, we simultaneously sequenced total DNA and cDNA from 392 HPV PCR-negative cervical cancers. Non-human reads were queried against all known HPVs. The complete database now contains PCR and/or deep sequencing data on 2850 invasive cervical cancers. RESULTS: HPV sequences were detected in 169/392 of HPV PCR-negative cervical cancers. Overall, 30 different HPV types were detected, but only 5 types were present in proportions above 3% of cancers. More than 92% of tumours were HPV-positive in PCR and/or sequencing (95% confidence interval: 91.1-93.1%). Exploring possible reasons for failure to previously detect HPV suggest that more sensitive type-specific PCRs for HPV 31, 33, 45 and 73 targeting retained regions of HPV would have detected most of these (117/392). CONCLUSIONS: Unbiased deep sequencing provides comprehensive data on HPV types in cervical cancers and appears to be an important tool for quality assurance of HPV screening.

HPV Types in Cervical Precancer by HIV Status and Birth Region: A Population-Based Register Study.

BACKGROUND: Data are lacking regarding which human papillomavirus (HPV) types cause high-grade cervical neoplasia (CIN2+) in people with HIV in Europe. We assessed which HPV types are associated with CIN2+ in women living in Sweden by HIV status. METHODS: The Swedish National HIV Registry, the Swedish Population Registry, and the Swedish National Cervical Screening Registry were linked. CIN2+ tissue blocks of 130 women living with HIV (WLWH) and 234 HIV-negative women, matched for country of birth (1:2), were retrieved from bio-banks and HPV genotyped. Adjusted ORs (adjOR), stratified by country of birth, were calculated using conditional logistic regression. Matching was broken for cross-group comparisons. RESULTS: WLWH with CIN2 were less likely to have HPV16 [14% vs. 40%; adjOR 0.1; 95% confidence interval (CI), 0.04-0.56] than HIV-negative women, but among women with CIN3, there was no difference in HPV16 prevalence by HIV status (adjOR 0.9; 95% CI, 0.51-1.70). WLWH were six times more likely to have HPV35 in CIN3 than HIV-negative women (adjOR 6.2; 95% CI, 1.3-30.4). WLWH from sub-Saharan Africa (SSA) had less 9-valent vaccine types, compared with both HIV-negative women born in Sweden (adjOR 0.1; 95% CI, 0.02-0.44) and WLWH born in Sweden (adjOR 0.1; 95% CI, 0.01-0.73), mostly because of decreased HPV16 and increased HPV35. CONCLUSIONS: WLWH from SSA were less likely to be covered by the 9-valent vaccine, mostly due to less HPV16 and more HPV35. IMPACT: This could have implications for HPV vaccines, currently not including HPV35, and for HPV-screening algorithms in women with origin from SSA.

Sequencing detects human papillomavirus in some apparently HPV-negative invasive cervical cancers.

Introduction. Cervical cancer is caused by human papillomavirus (HPV), but some cases may test HPV-negative. We previously tested 2850 Swedish cases and found that 394/2850 (13.8 %) cases tested HPV DNA-negative by PCR. Sequencing is the most thorough method to assess HPV status.Aim. We wished to assess whether deep sequencing might detect HPV sequences among these HPV-negative cervical cancer specimens, and to increase the likelihood of detecting transcriptionally active infections.Methodology. Out of the 2850 cancer cases, we sequenced a random sample of 92 HPV PCR-negative cervical cancers and 34 HPV PCR-positive cervical cancers. Four pools of blank blocks were sequenced as negative controls. To enrich for mRNA - a hallmark of active viral infection - the samples were extracted, reverse-transcribed, rRNA-depleted and then sequenced using the NovaSeq 6000 system (Illumina, USA). High-quality reads were aligned to the human genome and non-human reads were queried against HPV proteins.Results. We obtained a median of 23 million paired reads per sample. HPV was detected in 31/34 HPV PCR-positive cases. Among cases negative for HPV by PCR, 48/92 (52.2 %) contained HPV sequences, with HPV33 being the most commonly detected type among these (14/48 cases, 29.2 %). Comparison of the ratio of exon and intron sequences found that the sequenced material contained both DNA and RNA. Splice junctions were detected in 12 cases.Conclusion. Apparently, some cervical cancers contain HPV that is difficult to detect by PCR. Sequencing may be a helpful tool for additional quality assurance for HPV testing methods.

Cervical cancer case-control audit: Results from routine evaluation of a nationwide cervical screening program.

Our study used a refined case-control cervical cancer Audit framework to investigate effectiveness of cervical screening, with measures of three screening failures: irregular-participation, cervical cancer developed after cytological abnormalities and after normal screening results. The register-based study included 4,254 cervical cancer cases diagnosed in Sweden during 2002-2011, and 30 population-based controls per case. We used conditional logistic regression models to examine relative risks of cervical cancer in relation to screening participation and screening results in the past two screening rounds from 6 months before cancer diagnosis. We found that women unscreened in past two screening rounds showed four times increased risk of cervical cancer compared to women screened in time (OR = 4.1, 95% CI = 3.8-4.5), and women unscreened in the previous round but screened in the most recent round also showed a statistically significantly elevated risk (OR = 1.6, 95% CI = 1.5-1.8). Women having abnormality in previous two rounds exhibited higher risk of cervical cancer compared to women screened with normal results, while having normal results in the subsequent round after the abnormality also yielded an increased risk (OR = 4.0, 95% CI = 3.2-5.1). Being screened with only normal results was associated with 89% risk reduction for squamous cell cancer, compared to women unscreened, but only 60% reduction for adenocarcinoma. Our findings emphasize the importance of routine participation in cervical screening and suggest that management of abnormalities, as well as sensitivity of the test, warrants improvement especially for preventing cervical adenocarcinoma. The Audit framework serves as routine evaluation model and the findings benchmark for future evaluation of changes in screening practice.

Cervical screening and risk of adenosquamous and rare histological types of invasive cervical carcinoma: population based nested case-control study.

OBJECTIVES: To examine the association of cervical cytology screening with the risk of adenosquamous cell carcinoma (ASC) and rare histological types of invasive cervical carcinoma (RICC), using comprehensive registry data, and to assess tumour human papillomavirus status of ASC and RICC. DESIGN: Nationwide, population based, nested case-control study. SETTING: Sweden. PARTICIPANTS: All cases of invasive cervical carcinoma in Sweden during 2002-11 (4254 confirmed cases after clinical and histopathological review). 338 cases were neither squamous cell carcinoma nor adenocarcinoma, including 164 cases of ASC and 174 cases of RICC (glassy cell carcinoma, clear cell carcinoma, small cell carcinoma, neuroendocrine cell carcinoma, large cell carcinoma, and undifferentiated carcinoma). 30 birth year matched controls from the general Swedish population were matched to each case by applying incidence density sampling. MAIN OUTCOME MEASURES: Conditional logistic regression was used to calculate odds ratios, interpreted as incidence rate ratios, for risk of ASC and RICC in relation to screening status and screening history, adjusted for education. Human papillomavirus distribution of ASC and RICC was based on available archival tumour tissues from most Swedish pathology biobanks. RESULTS: Women with two screening tests in the previous two recommended screening intervals had a lower risk of ASC (incidence rate ratio 0.22, 95% confidence interval 0.14 to 0.34) and RICC (0.34, 0.21 to 0.55), compared with women without any test. High risk human papillomavirus was detected in 148/211 (70%) cases with valid human papillomavirus results from tumour tissues. The risk reduction among women with tumours that were positive (incidence rate ratio 0.28, 0.18 to 0.46) and negative (0.27, 0.13 to 0.59) for high risk human papillomavirus was similar, compared with women who did not attend any test. CONCLUSIONS: Cervical screening is associated with reduced risk of ASC and RICC, and most ASC and RICC are positive for high risk human papillomavirus. This evidence provides a benchmark for evaluating future cervical screening strategies.

High-risk human papillomavirus status and prognosis in invasive cervical cancer: A nationwide cohort study.

BACKGROUND: High-risk human papillomavirus (hrHPV) infection is established as the major cause of invasive cervical cancer (ICC). However, whether hrHPV status in the tumor is associated with subsequent prognosis of ICC is controversial. We aim to evaluate the association between tumor hrHPV status and ICC prognosis using national registers and comprehensive human papillomavirus (HPV) genotyping. METHODS AND FINDINGS: In this nationwide population-based cohort study, we identified all ICC diagnosed in Sweden during the years 2002-2011 (4,254 confirmed cases), requested all archival formalin-fixed paraffin-embedded blocks, and performed HPV genotyping. Twenty out of 25 pathology biobanks agreed to the study, yielding a total of 2,845 confirmed cases with valid HPV results. Cases were prospectively followed up from date of cancer diagnosis to 31 December 2015, migration from Sweden, or death, whichever occurred first. The main exposure was tumor hrHPV status classified as hrHPV-positive and hrHPV-negative. The primary outcome was all-cause mortality by 31 December 2015. Five-year relative survival ratios (RSRs) were calculated, and excess hazard ratios (EHRs) with 95% confidence intervals (CIs) were estimated using Poisson regression, adjusting for education, time since cancer diagnosis, and clinical factors including age at cancer diagnosis and International Federation of Gynecology and Obstetrics (FIGO) stage. Of the 2,845 included cases, hrHPV was detected in 2,293 (80.6%), and we observed 1,131 (39.8%) deaths during an average of 6.2 years follow-up. The majority of ICC cases were diagnosed at age 30-59 years (57.5%) and classified as stage IB (40.7%). hrHPV positivity was significantly associated with screen-detected tumors, young age, high education level, and early stage at diagnosis (p < 0.001). The 5-year RSR compared to the general female population was 0.74 (95% CI 0.72-0.76) for hrHPV-positive cases and 0.54 (95% CI 0.50-0.59) for hrHPV-negative cases, yielding a crude EHR of 0.45 (95% CI 0.38-0.52) and an adjusted EHR of 0.61 (95% CI 0.52-0.71). Risk of all-cause mortality as measured by EHR was consistently and statistically significantly lower for cases with hrHPV-positive tumors for each age group above 29 years and each FIGO stage above IA. The difference in prognosis by hrHPV status was highly robust, regardless of the clinical, histological, and educational characteristics of the cases. The main limitation was that, except for education, we were not able to adjust for lifestyle factors or other unmeasured confounders. CONCLUSIONS: In this study, women with hrHPV-positive cervical tumors had a substantially better prognosis than women with hrHPV-negative tumors. hrHPV appears to be a biomarker for better prognosis in cervical cancer independent of age, FIGO stage, and histological type, extending information from already established prognostic factors. The underlying biological mechanisms relating lack of detectable tumor hrHPV to considerably worse prognosis are not known and should be further investigated.

Viruses in cancers among the immunosuppressed.

Most cancer forms known to be caused by viruses are increased among the immunosuppressed, but several cancer forms without established viral etiology are also increased, notably nonmelanoma skin carcinoma (NMSC). We followed all 13,429 solid organ transplantation patients in Sweden for cancer occurrence after transplantation. We requested these tumor specimens and sequenced the first 89 specimens received (62 NMSCs, 27 other cancers). The sequences were analyzed for viruses based on two bioinformatics algorithms (paracel-blast (sensitive for detection of known viruses) and hidden Markov model (HMM; sensitive for distantly related viruses)). Among the 62 NMSCs, the virus family detected in the largest proportion of specimens was Mimiviridae (9/62 NMSCs). The majority of the virus-related reads belonged to Papillomaviridae. The HMM analysis identified 86 additional previously not described viral contigs related to 11 virus families, with reads related to Mimiviridae being the most common (detected in 28/62 NMSCs) with the most prevalent contig (Mimivirus SE906, 1937 bp) detected in 17/62 NMSCs. Among the 27 other cancers, viral sequences were detected in only 5 specimens by blast analysis, compared to in all 27 specimens by HMM (Mimiviridae, Poxviridae, Phycodnaviridae and virus-related sequences yet unclassified to any family). 99% of the virus reads belonged to a single previously not described sequence (Mimivirus SE996, 911 bp). A multitude of viruses is readily detectable in specimens with cancers occurring among the immunosuppressed, with sequences related to Mimiviridae being the most prevalent. Further research would be needed to elucidate the biological significance of the viruses.

Viruses in case series of tumors: Consistent presence in different cancers in the same subject.

Studies investigating presence of viruses in cancer often analyze case series of cancers, resulting in detection of many viruses that are not etiologically linked to the tumors where they are found. The incidence of virus-associated cancers is greatly increased in immunocompromised individuals. Non-melanoma skin cancer (NMSC) is also greatly increased and a variety of viruses have been detected in NMSC. As immunosuppressed patients often develop multiple independent NMSCs, we reasoned that viruses consistently present in independent tumors might be more likely to be involved in tumorigenesis. We sequenced 8 different NMSCs from 1 patient in comparison to 8 different NMSCs from 8 different patients. Among the latter, 12 different virus sequences were detected, but none in more than 1 tumor each. In contrast, the patient with multiple NMSCs had human papillomavirus type 15 and type 38 present in 6 out of 8 NMSCs.