Recent advances in prophylactic human papillomavirus (HPV) vaccination: a review of key literature published between September 2017 and September 2018.

Prophylactic human papillomavirus (HPV) vaccines represent a revolutionary approach in preventing and potentially eliminating HPV-related cancers. Overwhelming real-life data are confirming the high efficacy and exceptional safety profile of all three prophylactic HPV vaccines currently available, which was previously shown in pivotal clinical trials. In this review, we summarized and discussed in our opinion the most influential peer-reviewed literature published between September 2017 and September 2018; that is, during the 2017/2018 school year in Slovenia. We mainly focus on publications on progress and the development of novel prophylactic HPV vaccines, efficacy clinical trials evaluating various dosing schemes and HPV vaccination of alternative populations, and studies contributing to the mounting evidence for the real-life effectiveness of prophylactic HPV vaccines from several countries with successfully implemented HPV vaccination programs. In addition, we present the most important safety data from large population-based cohorts evaluating potential adverse events, briefly describe the most notable HPV vaccine-related crises, and provide insight into various responses by healthcare authorities that have resulted in markedly different outcomes in the vaccination perception of the general population and, consequently, HPV vaccine uptake. Finally, global disparities in access to HPV vaccines reveal substantial gender and socioeconomic inequity that must be overcome to achieve a large population impact of HPV vaccines worldwide.

Progress in prophylactic human papillomavirus (HPV) vaccination in 2016: A literature review.

Prophylactic human papillomavirus (HPV) vaccine represents a revolutionary step forward in preventing HPV-related cancers, especially cervical carcinoma. Alongside appropriate screening, it has the potential to dramatically reduce cervical cancer incidence and even eradicate it. Following extensive evaluations in clinical trials, the first decade of routine HPV vaccine use provides overwhelming evidence of the vaccines' safety and their real-life effectiveness. In 2016, further clinical trials showed high vaccine efficacy in adult women, especially those that were HPV DNA-negative at baseline, and indicated possible protection from HPV-related diseases after treatment of precancerous cervical lesions. The recommendation for a two-dose schedule in individuals under 15 is further supported for all three licensed vaccines by immunogenicity studies that show non-inferior immune responses and similar clinical efficacy compared to the three-dose schedule. So far, natural competition between HPV types has not been confirmed and therefore vaccine-induced clinically significant type replacement is unlikely. The real-world effectiveness data showed cross-sectional reduction in the prevalence/incidence of vaccine-related HPV types, genital warts and precancerous cervical lesions in countries and regions with HPV vaccination coverage. These declines were evident not only in vaccinated females, but also in unvaccinated females and males, strongly suggesting herd protection. Despite an excellent safety profile consistently demonstrated in clinical trials and confirmed in real-life settings, recently invented controversial syndromes allegedly linked to HPV vaccines temporarily compromised some previously very successful vaccination programs and significantly contributed to the failure of HPV vaccine implementation in some countries with the highest prevalence of cervical cancer. However, several safety studies failed to confirm any association of these syndromes with HPV vaccination in various settings and geographic locations. The main challenges remain implementing HPV vaccination in national vaccination programs, especially in low-and middle-income countries with the highest burden of cervical cancer, and achieving and sustaining high vaccine coverage rates.

Prevalence, genotype distribution, and risk factors for hepatitis C infection among HIV-infected individuals in Slovenia: a 1986-2013 update.

INTRODUCTION: Since the introduction of highly active antiretroviral therapy, chronic hepatitis C has become one of the leading causes of non-AIDS-related morbidity and mortality in patients with HIV infection. Two previous Slovenian nationwide studies published in 2002 and 2009 showed a very low prevalence of hepatitis C virus (HCV) infection among Slovenian HIV-infected individuals (14.5% and 10.7%, respectively). METHODS AND RESULTS: The presence of HCV infection was tested in 579/639 (90.6%) patients that were confirmed as HIV-positive in Slovenia by the end of 2013. Among them, 7.6% (44/579) of HIV-infected individuals were anti-HCV-positive, and 33/44 (75%) anti-HCV-positive patients were also HCV RNA-positive. HCV genotype 1 was most prevalent among HIV-infected patients (68%), followed by genotype 3 (20%), genotype 4 (8%), and genotype 2 (4%). Anti-HCV positivity was significantly higher in those that acquired HIV by the parenteral route (91.8%) than in those that acquired HIV by the sexual route (2.8%). DISCUSSION: Slovenia remains among the countries with the lowest prevalence of HCV infection in HIV-infected individuals. Because the burden of HIV among men who have sex with men in Slovenia is disproportionately high and increasing rapidly, the current favorable situation could change quickly and should be therefore monitored regularly.

Genomic diversity of low-risk human papillomavirus genotypes HPV 40, HPV 42, HPV 43, and HPV 44.

In order to investigate the genomic diversity of low-risk human papillomavirus (HPV) genotypes, a total of 108 isolates of HPV 40, HPV 42, HPV 43, or HPV 44, obtained from anal swabs or tissue specimens of patients with anogenital warts, and cervical swabs of women with cervical intraepithelial neoplasia of different grades, were analyzed. The characterization of genomic variants was established by sequencing one third of the viral genome and analysis of three different genomic regions: L1, LCR, and E6. Maximum variant divergence accounted for 0.4-1.1% of the investigated genomic segments. Several novel, potentially important nucleotide substitutions, deletions, and insertions are described. Altogether, among 14 HPV 40 isolates, a total of nine different genomic variants were identified, composed of eight L1, five LCR, and four E6 genomic variants. Among 49 HPV 42 isolates, a total of 30 genomic variants were identified, composed of 20 L1, 18 LCR, and four E6 genomic variants. Among 10 HPV 43 isolates, distributed into two major genomic variant lineages with clearly defined nucleotide signatures, three genomic variants were identified, composed of three L1, two LCR, and two E6 genomic variants. Among 35 HPV 44 isolates, a total of eight HPV 44 and 11 subtype HPV 44 genomic variants were identified, composed of 13 L1, 14 LCR, and 6 E6 genomic variants. A similar level of genomic diversity of HPV 44 and its subtype was identified in our geographic region as has been reported previously on isolates collected worldwide.

Human papillomavirus prevalence and type-distribution, cervical cancer screening practices and current status of vaccination implementation in Central and Eastern Europe.

We present a review of current cervical cancer screening practices, the implementation status of vaccination against human papillomaviruses (HPV) and available data concerning the burden of HPV infection and HPV type-specific distribution in 16 Central and Eastern European countries: Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Montenegro, Poland, Romania, Serbia, Slovakia, Slovenia and the Former Yugoslav Republic (FYR) of Macedonia. Since published data were relatively scarce, two detailed surveys were conducted during August-October 2011 and in January 2013 to obtain relevant and updated information. The mean prevalence of HPV infection in 8610 women with normal cervical cytology from the region was 12.6%, with HPV16 being the most frequent HPV type. The overall HPV DNA prevalence in women with high-grade cervical lesions was 78.1%. HPV DNA was found in 86.6% of cervical cancers; the combined prevalence of HPV16/18 among HPV positive cases was 87.5%. The overall HPV DNA prevalence in genital warts and laryngeal papillomas was 94.8% and 95.2%, respectively, with HPV6 and HPV11 being the most frequent types. Opportunistic and organized cervical screening, mainly based on conventional cytology, is performed in nine and seven countries in the region, respectively, with the proposed age of the start of screening ranging from 20 to 30 years and the estimated coverage ranging from a few percent to over 70%. At least one of the current HPV prophylactic vaccines is registered in all Central and Eastern European countries except Montenegro. Only Bulgaria, Czech Republic, FYR Macedonia, Latvia, Romania and Slovenia have actually integrated HPV vaccination into their national immunization programme and currently provide routine vaccination free of charge to the primary target population. The key reasons for lack of implementation of HPV vaccination into the national immunization programme are high vaccine cost and negative public perception. This article forms part of a regional report entitled "Comprehensive Control of HPV Infections and Related Diseases in the Central and Eastern Europe and Central Asia Region" Vaccine Volume 31, Supplement 7, 2013. Updates of the progress in the field are presented in a separate monograph entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Human papillomavirus (HPV) prevalence and HPV type distribution in cervical, vulvar, and anal cancers in central and eastern Europe.

INTRODUCTION: High-risk human papillomaviruses (HPV) play the leading etiological role in the development of cervical, anal, and vaginal cancers and a substantial proportion of penile, vulvar, and oropharyngeal (tonsillar) cancers. METHODS: The article summarizes the results of the most important studies that examined tissue specimens of cervical, anal, and vulvar carcinoma from 16 central and eastern European countries for the presence of HPV DNA. RESULTS: Twenty-eight eligible studies were identified. Among 2,531 invasive cervical cancers, 86.6% were HPV-positive. The combined prevalence of HPV-16/18 among HPV-positive cervical cancers was 87.5%. The overall prevalence of HPV DNA in six studies of anal carcinomas (43 cases) and vulvar carcinomas (164 cases) was 90.7% and 32.9%, respectively. HPV-16 DNA was detected in 86% of all anal carcinomas studied, and the proportion of HPV-16 positive vulvar carcinomas varied from 10.9% to 27.5%. HPV-18 DNA was not detected in any anal or vulvar carcinoma studied. CONCLUSIONS: HPV prevalence and type distribution among women with cervical cancer in central and eastern Europe is comparable with other European regions. Several gaps in knowledge exist in the region concerning HPV prevalence and type distribution among women with HPV-related cancers other than cervical cancer and in the general population.

Current status of human papillomavirus vaccination implementation in central and eastern Europe.

We present a review of the current implementation status of vaccination against human papillomaviruses (HPV) and available data concerning the burden of HPV infection and HPV type-specific distribution in 16 central and eastern European countries: Albania, Bosnia and Herzegovina, Bulgaria, Croatia, the Czech Republic, Estonia, Montenegro, Poland, Romania, Serbia, Slovakia, Slovenia, and The Former Yugoslav Republic of Macedonia. At least one current HPV prophylactic vaccine is registered in all central and eastern European countries except Montenegro. Six counties-Bulgaria, the Czech Republic, Latvia, Romania, Slovenia, and Former Yugoslav Republic of Macedonia-have integrated the HPV vaccination into their national immunization program and currently provide routine vaccination free of charge to the primary target population. Ten countries have not integrated HPV vaccination into the national immunization program. The key reasons for lack of implementation of HPV vaccination into the national immunization program are the high vaccine cost and negative public perception. Vaccination of males is not recommended in any country in the region.

Cervical cancer screening practices in central and eastern Europe in 2012.

The burden of cervical cancer in central and eastern Europe is generally higher compared to western or northern Europe due to a history of mostly opportunistic cervical cancer screening practices and due to the strong influence of political and economic changes in post-communist transition. This article describes the current cervical cancer screening practices, organizational plans for the future, and main obstacles that need to be overcome in 16 countries in central and eastern Europe: Albania, Bosnia and Herzegovina, Bulgaria, Croatia, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Montenegro, Poland, Romania, Serbia, Slovakia, Slovenia and The former Yugoslav Republic of Macedonia. Unfortunately, only a few countries have managed to establish an organized and well-functioning cervical cancer screening program in recent years, whereas most countries in the region are still struggling with implementation-related issues of organized cervical cancer screening. Encouragingly, even in the countries where only opportunistic screening is performed, well-prepared plans and strategies have been established for switching to organized screening in the near future.

Short communication: prevalence of HIV type 1 transmitted drug resistance in Slovenia: 2005-2010.

Slovenia is a small European country with a total of 547 HIV-infected individuals cumulatively reported by the end of 2011. However, the estimated incidence rate of HIV infections increased from 7.0 per million in 2003 to 26.8 per million in 2011. In this study, we assessed the prevalence of transmitted drug resistance (TDR) in the past 6 years (2005-2010) and analyzed the time trend of the proportion of men having sex with men (MSM) and HIV-1 subtype B among newly diagnosed individuals in a 15-year period (1996-2010) in Slovenia. Among 150 patients included in the study, representing 63% of HIV-1 newly diagnosed patients in 2005-2010, TDR was found in seven patients (4.7%). The prevalence of TDR to nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, and protease inhibitors was 2% (3/150), 2% (3/150), and 0.7% (1/150), respectively. The majority of patients were infected with subtype B (134/150, 89%), while subtype A was detected in 6.0% (9/150), subtype D in 1.3% (2/150), and subtype G and CRF02_AG in 0.7% (one patient each). Three of 150 sequences could not be typed. Infection with subtype B was found to be significantly associated with male gender, Slovenia being reported as the country of the patient's nationality and origin of the virus, CDC class A, mode of transmission with homosexual/bisexual contact, sex with an anonymous person, and a higher CD4(+) count. Among patients carrying the subtype B virus, an MSM transmission route was reported in 87% of patients. Although the prevalence of TDR in Slovenia is still below the European average, active surveillance should be continued, especially among MSM, the most vulnerable population for HIV-1 infection in this part of Europe.

Identical human papillomavirus (HPV) genomic variants persist in recurrent respiratory papillomatosis for up to 22 years.

Seventy initial and 125 follow-up tissue specimens of laryngeal papillomas, obtained from 70 patients who had had recurrent respiratory papillomatosis for from 1-22 years, were investigated for the presence of human papillomavirus (HPV) DNA and HPV E5a, LCR and/or full-length genomic variants. HPV-6 was found in 130/195, HPV-11 in 63/195, and HPV-6/HPV-11 in 2/195 samples. Within 67/70 (95.7%) patients, all follow-up HPV isolates genetically matched completely initial HPV isolate over the highly variable parts of the genome or over the entire genome. Frequent recurrence of laryngeal papillomas is a consequence of long-term persistence of the identical initial HPV genomic variant.

Comparative evaluation of the Abbott RealTime High Risk HPV test and INNO-LiPA HPV Genotyping Extra test for detecting and identifying human papillomaviruses in archival tissue specimens of head and neck cancers.

INTRODUCTION: The Abbott RealTime is a novel real-time PCR assay designed for concurrent individual genotyping of HPV16 and HPV18 and pooled detection of 12 HPV genotypes: HPV31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68 in cervical swab specimens. In this study, the performance of RealTime for detecting HPV in formalin-fixed, paraffin-embedded tissue specimens of head and neck cancers was compared to the Innogenetics INNO-LiPA assay, which allows identification of 28 HPVs, including all 14 covered by RealTime. METHODS: A total of 60 FFPE tissue specimens obtained from the same number of patients with histologically confirmed cancer of the oral cavity or oropharynx were included in the study. Following DNA extraction using a Qiagen DNA Mini Kit, RealTime and INNO-LiPA were performed on all samples, as instructed by the manufacturers. RESULTS: A 136-bp fragment of human beta-globin serving as an internal control in RealTime was successfully amplified from all 60 tissue samples included in the study. RealTime and INNO-LiPA showed 100% agreement and detected HPV DNA in 5/60 (8.3%) of the cancer samples, which all contained genotype HPV16. CONCLUSIONS: RealTime assay is a reliable, sensitive, and specific diagnostic tool for the detection and partial genotyping of targeted HPV genotypes in FFPE tissue specimens of oral and oropharyngeal cancer.

Classification and nomenclature system for human Alphapapillomavirus variants: general features, nucleotide landmarks and assignment of HPV6 and HPV11 isolates to variant lineages.

BACKGROUND: Papillomaviruses constitute a family of viruses that can be classified into genera, species and types based on their viral genome heterogeneity. Currently circulating infectious human Alphapapillomaviruses (alpha-PVs) constitute a set of viral genomes that have evolved from archaic times and display features of host co-speciation. Viral variants are more recently evolved genomes that require a standardized classification and nomenclature. OBJECTIVES: To describe a system for the classification and nomenclature of HPV viral variants and provide landmarks for the numbering of nucleotide positions. METHODS: The complete 8 kb genomes of the alpha-9 species group and HPV6 and 11 types, collected from isolates throughout the world were obtained from published reports and GenBank. Complete genomes for each HPV type were aligned using the E1 start codon and sequence divergence was calculated by global and pairwise alignments using the MUSCLE program. Phylogenetic trees were constructed from the aligned sequences using a maximum likelihood method (RAxML). RESULTS: Pairwise comparisons of nucleotide differences between complete genomes of each type from alpha-9 HPV isolates (HPV16, 31, 33, 35, 52, 58 and 67) revealed a trimodal distribution. Maximum heterogeneity for variants within a type varied from 0.6%-2.3%. Nucleotide differences of approximately 1.0%-10.0% and 0.5%-1.0% of the complete genomes were used to define variant lineages and sublineages, respectively. Analysis of 43 HPV6 complete genomes indicated the presence of 2 variant lineages, whereas 32 HPV11 isolates were highly similar and clustered into 2 sublineages. A table was constructed of the human alpha-PV landmark nucleotide sequences for future reference and alignments. CONCLUSIONS: A proposed nomenclature system for viral variants and coordination of nucleotide positions will facilitate the comparison of variants across geographic regions and amongst different populations. In addition, this system will facilitate study of pathogenic, tissue tropism and functional differences amongst variant lineages of and polymorphisms within HPV variants.

Pre-vaccination genomic diversity of human papillomavirus genotype 6 (HPV 6): a comparative analysis of 21 full-length genome sequences.

Comparative analysis of 21 full-length genome sequences of human papillomavirus genotype 6 (HPV 6): 18 determined in this study and three sequences available in nucleotide sequence databases, revealed more than 98% nucleotide similarity to the HPV 6 prototype isolate. The minimum and maximum genomic distance between the full-length genomic variants and the prototype sequence was three nucleotide substitutions, and 122 nucleotide substitutions and three insertions, respectively. Detailed sequence analysis of early viral genes E7, E1, E2 and E4, late viral gene L2, and three non-classic non-coding genomic regions (NNCR) revealed the existence of at least four E7, twelve E1, eleven E2, six E4, eleven L2, two NNCR1, two NNCR2, and three NNCR3 genomic variants. In addition, several novel, potentially important amino acid mutations were identified. A phylogenetic tree calculated from viral genome sequences was dichotomic, separating all isolates into HPV 6b (prototypic) and HPV 6a/6vc (non-prototypic) genetic lineages. This study, which contributed the largest number of full-length HPV 6 genome sequences to date, confirmed that HPV 6 diversifies virtually equally across the entire genome by nucleotide (amino acid) exchanges in coding regions and additional nucleotide insertions/deletions in non-coding regions. However, this diversification trend was more evident in non-coding regions LCR and NNCR3 and early viral genes E4, E5a and E5b.

Prevaccination genomic diversity of human papillomavirus genotype 11: a study on 63 clinical isolates and 10 full-length genome sequences.

Prevaccination genomic diversity of human papillomavirus genotype 11 (HPV 11) was established by sequencing 40% of the genome of 63 clinical isolates obtained from an ethnogeographically closed Caucasian cohort, and full-length genome sequencing of the ten most divergent isolates. In the study, which included the largest number of isolates to date, by analyzing pooled L1, LCR, E6, E5a, and E5b sequences (3,217 bp) of an individual isolate, a total of 23 genomic variants were identified, of which three (5 isolates) and twenty (58 isolates) corresponded to prototypic and non-prototypic variant groups, respectively. Several novel, potentially important mutations are described. Full-length genome sequences of ten isolates revealed more than 99% similarity to the HPV 11 prototype isolate. The minimum genomic distance between the full-length sequences of genomic variants and the prototype was 3 point mutations and 2 inserts and the maximum distance 31 point mutations, one insertion and one deletion. Within the ethnogeographically closed cohort investigated in this study, HPV 11 was shown to be less polymorphic in comparison to the majority of HPV genotypes studied to date.

Detection and typing of low-risk human papillomavirus genotypes HPV 6, HPV 11, HPV 42, HPV 43 and HPV 44 by polymerase chain reaction and restriction fragment length polymorphism.

A novel PCR-restriction fragment length polymorphism assay (PCR-RFLP) was developed for sensitive detection and reliable differentiation of five low-risk human papillomavirus (lr-HPV) genotypes: HPV 6, HPV 11, HPV 42, HPV 43 and HPV 44, as well as differentiation of prototypic and non-prototypic HPV 6 genomic variants. The assay is based on the amplification of a 320-bp fragment of the HPV E1 gene and subsequent analysis of PCR-products with BsaJI and HinFI. Testing on plasmid standards showed that PCR-RFLP enabled simple and reliable identification and differentiation of five targeted lr-HPV genotypes and could detect reproducibly down to 10 copies of viral genome equivalents per PCR. The PCR-RFLP showed almost complete agreement with previously obtained genotyping results on 42 HPV-DNA negative samples and 223 HPV-DNA positive samples (45 HPV 6, 34 HPV 11, 35 HPV 42, 10 HPV 43, 24 HPV 44 positive samples and 75 samples containing 28 non-targeted HPV genotypes). The novel assay is simple and robust, does not require any sophisticated equipment and can be of great value for epidemiological studies, particularly in settings in which financial resources are limited.

Human papillomaviruses (HPV) in tissue specimens of oral squamous cell papillomas and normal oral mucosa.

BACKGROUND: The etiology of oral squamous cell papillomas (OSCP) is still unresolved. MATERIALS AND METHODS: The presence of human papillomavirus (HPV) was examined, using PCR and three different consensus primers, in tissue specimens obtained from 49 patients with OSCP and 49 tissue specimens of histologically-normal oral mucosa obtained from the same number of individuals, who matched the patients with OSCP in age, gender and localization of the obtained tissue specimens. RESULTS: Amplifiable DNA was recovered from 44 out of 49 and 45 out of 49 tissue specimens of OSCP and normal oral mucosa, respectively. HPV-6 was detected in three and HPV-16 in one out of 44 OSCP specimens tested. Three tissue specimens of normal oral mucosa were HPV DNA-positive, harboring HPV-6, HPV-11 and HPV-31. CONCLUSION: Since no significant difference in the prevalence of HPV DNA between the patients with OSCP and the control subjects (9.1% vs. 6.7%; p=0.694) was observed, HPV is deemed to play a limited role in the etiology of OSCP, at least in Europe.

Blood-stained letter received by HIV/AIDS reference laboratory in 1993--a historical case report.

We describe an interesting historical case of a blood-stained letter received in 1993 by Slovenian HIV/AIDS Reference Laboratory. According to the statement of the sender, the letter was spotted with HIV-infected blood. The polymerase chain reaction (PCR) amplification with two gag and env primer sets excluded the presence of HIV proviral DNA in the spot punches obtained from the dried blood spots. Although the presence of HV DNA was confirmed in 5 positive control blood spots using the same sets of primers, we still doubted in the accuracy of the HIV negative result. Fortunately, we obtained a serum sample of the author of the letter four months later from a psychiatric institution where he was hospitalized for paranoid schizophrenia. Since no anti HIV-1/2 antibodies were detected in his serum sample, our initial HIV negative findings based on PCR testing of blood spots were confirmed.