The Swedish Cervical Screening Cohort.

The Cervical Screening Cohort enrols women screened for human papillomavirus (HPV) and cervical abnormalities within the capital region of Sweden from the organised screening program and the non-organised testing of cervical samples. The cohort started in 2011 and has enrolled more than 670,000 women, contributing with more than 1.2 million biobanked samples.

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.

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.

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.

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).

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.

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.

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.

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.

De novo sequence assembly requires bioinformatic checking of chimeric sequences.

De novo assembly of sequence reads from next generation sequencing platforms is a common strategy for detecting presence and sequencing of viruses in biospecimens. Amplification artifacts and presence of several related viruses in the same specimen can lead to assembly of erroneous, chimeric sequences. We now report that such chimeras can also occur between viral and non-viral biological sequences incorrectly joined together which may cause erroneous detection of viruses, highlighting the importance of performing a chimera checking step in bioinformatics pipelines.

Differing Age-Specific Cervical Cancer Incidence Between Different Types of Human Papillomavirus: Implications for Predicting the Impact of Elimination Programs.

The elimination of cervical cancer rests on high efficacy of human papillomavirus (HPV) vaccines. The HPV type distribution among cases of invasive cervical cancer (ICC) is used to make predictions about the impact of eliminating different types of HPV, but accumulating evidence of differences in age-specific cancer incidence by HPV type exists. We used one of the largest population-based series of HPV genotyping of ICCs (n = 2,850; Sweden, 2002-2011) to estimate age-specific ICC incidence by HPV type and obtain estimates of the cancer-protective impact of the removal of different HPV types.

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

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.

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.

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.

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.

Nationwide comprehensive human papillomavirus (HPV) genotyping of invasive cervical cancer.

Background: The Swedish National Cervical Screening Registry collects and evaluates comprehensive, nationwide health data to optimise organised cervical cancer prevention. Since all cervical cancer specimens are saved in biobanks, population-based data from the specimens should be available for analysis and linkage with other health information.

Methods: We identified all cervical cancers diagnosed in Sweden during 2002-2011 (4254 confirmed cases) and requested the tissue blocks to retrieve human papillomavirus (HPV) genotype data using general primer PCR with Luminex genotyping and real-time PCR targeting the E6/E7 regions of HPV16/18.

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).

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.

Validation of a standardized extraction method for formalin-fixed paraffin-embedded tissue samples.

Background: Formalin-fixed paraffin-embedded (FFPE) samples can be DNA-extracted and used for human papillomavirus (HPV) genotyping. The xylene-based gold standard for extracting FFPE samples is laborious, suboptimal and involves health hazards for the personnel involved.

Objectives: To compare extraction with the standard xylene method to a xylene-free method used in an HPV LabNet Global Reference Laboratory at the Centers for Disease Control (CDC); based on a commercial method with an extra heating step.