Predicting past and future SARS-CoV-2-related sick leave using discrete time Markov modelling.

BACKGROUND: Prediction of SARS-CoV-2-induced sick leave among healthcare workers (HCWs) is essential for being able to plan the healthcare response to the epidemic. METHODS: During first wave of the SARS-Cov-2 epidemic (April 23rd to June 24th, 2020), the HCWs in the greater Stockholm region in Sweden were invited to a study of past or present SARS-CoV-2 infection. We develop a discrete time Markov model using a cohort of 9449 healthcare workers (HCWs) who had complete data on SARS-CoV-2 RNA and antibodies as well as sick leave data for the calendar year 2020. The one-week and standardized longer term transition probabilities of sick leave and the ratios of the standardized probabilities for the baseline covariate distribution were compared with the referent period (an independent period when there were no SARS-CoV-2 infections) in relation to PCR results, serology results and gender. RESULTS: The one-week probabilities of transitioning from healthy to partial sick leave or full sick leave during the outbreak as compared to after the outbreak were highest for healthy HCWs testing positive for large amounts of virus (ratio: 3.69, (95% confidence interval, CI: 2.44-5.59) and 6.67 (95% CI: 1.58-28.13), respectively). The proportion of all sick leaves attributed to COVID-19 during outbreak was at most 55% (95% CI: 50%-59%). CONCLUSIONS: A robust Markov model enabled use of simple SARS-CoV-2 testing data for quantifying past and future COVID-related sick leave among HCWs, which can serve as a basis for planning of healthcare during outbreaks.

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.

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 Vaccination and the Risk of Invasive Cervical Cancer.

BACKGROUND: The efficacy and effectiveness of the quadrivalent human papillomavirus (HPV) vaccine in preventing high-grade cervical lesions have been shown. However, data to inform the relationship between quadrivalent HPV vaccination and the subsequent risk of invasive cervical cancer are lacking. METHODS: We used nationwide Swedish demographic and health registers to follow an open population of 1,672,983 girls and women who were 10 to 30 years of age from 2006 through 2017. We assessed the association between HPV vaccination and the risk of invasive cervical cancer, controlling for age at follow-up, calendar year, county of residence, and parental characteristics, including education, household income, mother's country of birth, and maternal disease history. RESULTS: During the study period, we evaluated girls and women for cervical cancer until their 31st birthday. Cervical cancer was diagnosed in 19 women who had received the quadrivalent HPV vaccine and in 538 women who had not received the vaccine. The cumulative incidence of cervical cancer was 47 cases per 100,000 persons among women who had been vaccinated and 94 cases per 100,000 persons among those who had not been vaccinated. After adjustment for age at follow-up, the incidence rate ratio for the comparison of the vaccinated population with the unvaccinated population was 0.51 (95% confidence interval [CI], 0.32 to 0.82). After additional adjustment for other covariates, the incidence rate ratio was 0.37 (95% CI, 0.21 to 0.57). After adjustment for all covariates, the incidence rate ratio was 0.12 (95% CI, 0.00 to 0.34) among women who had been vaccinated before the age of 17 years and 0.47 (95% CI, 0.27 to 0.75) among women who had been vaccinated at the age of 17 to 30 years. CONCLUSIONS: Among Swedish girls and women 10 to 30 years old, quadrivalent HPV vaccination was associated with a substantially reduced risk of invasive cervical cancer at the population level. (Funded by the Swedish Foundation for Strategic Research and others.).

Impact of HPV vaccination on cervical screening performance: a population-based cohort study.

BACKGROUND: Human papillomavirus (HPV) vaccination is predicted to lower the positive predictive value (PPV) of cytology. METHODS: We included 153,250 girls born between 1989 and 1993, resident in Sweden since the introduction of HPV vaccines (October 2006) and attending cervical screening at age 23 years. We assessed their first cytology and following histopathological diagnosis using Swedish National Cervical Screening Registry (NKCx). By linkage with the national Swedish HPV vaccination registry, we determined PPV of abnormal cytology for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and the differences with 95% confidence intervals (CIs) according to vaccination status. RESULTS: The PPV of high-grade cytology for CIN2+ was 69.9% (95% CI, 67.9-71.9), 64.9% (95% CI, 59.8-69.8) and 57.4% (95% CI, 50.9-63.7) among women unvaccinated, initiating vaccination at age 17-22 years and initiating vaccination before age 17 years, corresponding to reduction in PPV by 8% (95% CI, 0-15%) and 17% (95% CI, 7-26%) in vaccinated groups after adjustment for birth cohort, respectively. CONCLUSION: The PPV of cytology for CIN2+ decreased among vaccinated women, and the decrease was stronger for girls vaccinated at younger ages. A switch from cytology to HPV testing might potentially improve the screening performance.

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.

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 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.

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. RESULTS: We obtained blocks from 2932/4254 (69%) of cases. Valid HPV genotyping data was retrieved for 2850 cases (97%). The most common type was HPV16 (60%), followed by HPV18 (19%), HPV45 (7%), HPV31 (3%), HPV33 (2%), HPV52 (2%), HPV39 (1%), HPV70 (1%), HPV56 (1%), HPV35 (1%), HPV58 (1%) and HPV59 (1%). Ninety-six percent of all HPV-positive cases had a single infection. Eighty-nine cases were HPV-positive only when testing for the HPV16/18-E6/E7 region. CONCLUSIONS: We present one of the largest series of HPV-genotyped cervical cancers to date. The systematic collection of cervical cancer HPV genotyping data by the screening registry will facilitate prevention and monitoring of HPV type-specific disease burden.

Use of a new global indicator for vaccine safety surveillance and trends in adverse events following immunization reporting 2000-2015.

Reporting of adverse events following immunization (AEFI) is a key component for functional vaccine safety monitoring system. The aim of our study is to document trends in the AEFI reporting ratio globally and across the six World Health Organization (WHO) regions. We describe the number of AEFI reports communicated each year through the World Health Organization/United Nations Children's Fund Joint Reporting Form on Immunization from 2000 to 2015. The AEFI reporting ratios (annual AEFI reports per 100,000 surviving infants) were calculated to identify WHO countries (n = 191 in 2000 and n = 194 by 2015) that met a minimal reporting ratio of 10, a target set by the Global Vaccine Action Plan for vaccine safety monitoring as a proxy measure for a functional AEFI reporting system. The number of countries reporting any AEFI fluctuated over time but with progress from 32 (17%) in 2000 to 124 (64%) in 2015. In 2015, the global average AEFI reporting ratio was 549 AEFI reports per 100,000 surviving infants. The number of countries with AEFI reporting ratios greater than 10 increased from 8 (4%) in 2000 to 81 (42%) in 2015. In 2015, 60% of countries in the WHO Region of the Americas reported at least 10 AEFI per 100,000 surviving infants, followed by 55% in European Region, 43% in Eastern Mediterranean Region, 33% in Western Pacific Region, 27% in South-East Asia Region and 21% in African Region. Overall, AEFI reporting has increased over the past sixteen years worldwide, but requires strengthening in a majority of low- and middle- income countries. The AEFI reporting ratio is useful for benchmarking and following trends over time; but does not provide information on the quality of the reporting system and does not guarantee capacity to detect and manage a vaccine safety problem at a national level. Additional efforts are required to ensure and improve data quality, AEFI reporting and surveillance of immunization safety in every country.

Permethrin modulates cholinergic mini-synaptic currents by partially blocking the calcium channel.

Pyrethroid insecticide modulation of the voltage-gated sodium channel (VGSC) is proposed to underlie their effects on neuronal excitability by inhibiting channel inactivation and increasing channel open time. However, some in vitro evidences indicate that target sites other than VGSCs could contribute to pyrethroid disruption of neuronal activity. Cholinergic excitability in Drosophila, as in other insects and mammals, is important for activity in the central nervous system. The effects of permethrin, a putative calcium antagonist, on calcium current and cholinergic mini-synaptic transmission were investigated in the Drosophila brain. At concentration of 2.5µM, permethrin significantly decreased the calcium current and cholinergic mini-synaptic current. However, the permethrin could not antagonize the calcium current completely. Removal of calcium from the external solution produced a significant decrease of cholinergic mini-synaptic transmission. The results are consistent with the hypothesis that permethrin may modulate cholinergic mini-synaptic currents by partially blocking the calcium channel.