Indian Journal of Medical Microbiology

HPV vaccines – A game changer for preventing HPV-related cancers

Human papillomaviruses (HPV) cause almost all cervical cancer cases globally, with the high-risk genotypes 16/18 causing at least 70 % of cancers, of which most cases occur in low-to-middle-income countries. Prophylactic vaccination plays a major role in the prevention of cervical cancer, which could effectively prevent the incidence of HPV infection. The L1 protein, which, when assembled into virus-like particles, induces HPV-type-specific neutralizing antibodies, which form the basis of all currently licensed HPV vaccines. There are six approved prophylactic HPV vaccines. All these vaccines are designed to prevent HPV 16 and 18-associated cervical precancers, thereby preventing approximately 70 % of the cancers. This review looks at the current HPV prophylactic vaccines, their mechanism of action, vaccination schedules, and the cost of different vaccines.

Human papillomavirus infection: Is it associated with epithelial ovarian cancer?

Human papillomavirus (HPV), the causative agent of cervical cancer, is associated with several other epithelial malignancies. Previous reports on HPV infection and its association with ovarian cancer are highly contradicting. Reports on HPV association with ovarian cancer in Indian women are also rare. Hence, the purpose of this study was to screen women with serous epithelial ovarian cancer for possible HPV infection. Tumor samples, collected at the time of surgery from 88 women with serous epithelial ovarian cancer were screened using a specific and sensitive PCR. The PCR results were confirmed with Southern blotting using HPV genome-specific probes, both of high-risk HPV type 16 and 18 and low-risk HPV type 6 and 11. All the samples were again tested for another 14 high-risk HPV genotypes with a commercially available qRT-PCR. All the samples screened and confirmed by various tests did not show presence of either low-risk or high-risk HPV DNA, indicating the absence of HPV infections in these ovarian cancer tissues. The present study shows that HPV infection may not be associated with epithelial ovarian cancer. The result of the current investigation strongly supports the results of earlier research that, HPV is not associated with ovarian cancer.

E6-E7 based nested multiplex PCR assay for genital HPV detection and simultaneous typing of 15 high and low-risk HPV types

Due to a wide range of Human Papillomavirus (HPV) types associated with genital cancers; HPV genotyping remains important for the introduction of an appropriate vaccine, disease diagnosis, follow-up and epidemiological surveys. Currently, available molecular genotyping assays are not only expensive but also requires dedicated and expensive equipment which is not feasible in the majority of low-and-middle-socioeconomic countries. The purpose of the study was to develop and evaluated a cost-effective nested-multiplex polymerase chain reaction (NM-PCR) assay for HPV genotyping. HPV-DNA containing plasmids and cervical scrapings from histologically confirmed cervical cancer cases were used to evaluate the NM-PCR. In the first round PCR, a set of consensus primers were used to amplify 38 mucosal HPV types. HPV Type-specific primers were used in the second-round polymerase chain reaction (PCR) to amplify 15 HPV types in three multiplex cocktails. The assay sensitivity was determined with the control panel containing one to 10 The assay was able to amplify all HPV types and detected as few as 50GE per reaction. A total of 23 endo-cervical samples obtained from healthy, HPV negative subjects and 52 histologically confirmed cervical scrapings were processed for HPV genotyping by NM-PCR. HPV DNA was detected in all histologically confirmed samples. DNA sequencing results showed complete concordance with PCR results. The designed nested PCR based assay had good concordance with clinical histology and sequencing results and appears to be a promising tool for HPV genotyping especially in resource-constrained settings.

HPV genotype prevalence in Indian women with cervical disease and estimation of the potential impact of HPV vaccines on prevention of cervical cancer

Human papillomavirus (HPV) causes genital and oropharyngeal cancers worldwide. There are significant gaps exist in the data on HPV genotype prevalence in this part of the country. HPV vaccination is one of the best preventive methods available currently. HPV genotyping plays an important role in the selection of appropriate vaccines and monitoring vaccine efficacy and coverage. The present study aimed to determine the HPV genotype prevalence and to estimate the potential impact of HPV vaccines on invasive cervical cancer. A total of 204 cervical biopsy samples collected from symptomatic women were subjected to an in-house designed and standardised nested multiplex PCR (NM-PCR) assay. The NM-PCR was designed to detect 38 Mucosal HPV types as a pooled result and genotyping of 15 HPV types. Further, the HPV genotype data was used to estimate the HPV vaccine bivalent, quadrivalent and nonavalent impact on the population using a mathematical formula. Out of 204 samples 188 were subjected to HPV-nested PCR. A total of 163 (86.7%) samples were positive for at least one HPV type. Multiple genotypes were identified in 30% of samples processed. HPV-16 (85.3%) was the most frequently detected genotype followed by HPV-18 (13.5%) and HPV-33 (11.0%). Other genotypes were observed less frequently. Based on the HPV prevalence observed in the study a mathematical model estimated the efficacy of bivalent, quadrivalent and nonavalent vaccines were 76.1%, 76.7%, and 91.1% (average) respectively. HPV-16 was the most prevalent (>85%) genotype detected in this study. Multiple infections observed in 30% of samples were quite high as compared to the majority of national, and global reference (15-25.4%) data. The Mathematical model showed that a nonavalent vaccine would give better protection.

Study on human papillomavirus (HPV) infection, typing, peripheral blood immune factor expression and vaginal microenvironment balance in cervical cancer screening population

Cervical cancer (CC) is a leading cause of cancer-related deaths among women, primarily driven by persistent high-risk human papillomavirus (HPV) infection. This study explores HPV prevalence, genotypes, and their associations with peripheral blood immune factors and vaginal microenvironment balance in a CC screening population. A total of 2467 women undergoing CC screening from January to June 2024 were included. Among these, 227 tested positive for HPV (infection rate: 9.20 %). Using random sampling and propensity score matching, 100 HPV-positive and 100 HPV-negative individuals were selected. The HPV-positive group was further divided into HPV16/18 and other HPV subtypes. Samples from cervical cells, secretions, and peripheral blood were analyzed for HPV genotyping, vaginal microenvironment parameters (pH, cleanliness, Trichomonas, hydrogen peroxide-producing bacteria), Th1/Th2 cytokines (IL-6, IL-10, TNF-α), and T cell subsets (CD4 HPV-positive patients exhibited higher vaginal pH, abnormal vaginal cleanliness, and elevated hydrogen peroxide-producing bacteria compared to HPV-negative patients (P < 0.05). HPV16/18-positive individuals had greater vaginal alterations than other HPV subtypes. CD4 HPV, particularly HPV16/18, is associated with immune imbalance and vaginal microenvironment disruptions, highlighting the need for tailored strategies to improve CC prevention and diagnosis.