Animal experiments show impact of vaccination on reduction of SARS-CoV-2 virus circulation: A model for vaccine development?

BACKGROUND: In the pre-clinical phase, SARS-CoV-2 vaccines were tested in animal models, including exposure trials, to investigate protection against SARS-CoV-2. These studies paved the way for clinical development. The objective of our review was to provide an overview of published animal exposure results, focussing on the capacity of vaccines to reduce/prevent viral shedding. METHOD: Using Medline, we retrieved eighteen papers on eight different vaccine platforms in four animal models. Data were extracted on presence/absence of viral RNA in nose, throat, or lungs, and neutralizing antibody levels in the blood. RESULTS: All vaccines showed a tendency of reduced viral load after exposure. Particularly nasal swab results are likely to give an indication about the impact on virus excretion in the environment. Similarly, the reduction or prevention of viral replication in the bronchoalveolar environment might be related with disease prevention, explaining the high efficacy in clinical trials. DISCUSSION: Although it remains difficult to compare the results directly, the potential for a strong reduction of transmission was shown, indicating that the animal models predicted what is observed in the field after large scale human vaccination. This merits further attention for standardization of exposure experiments, with the intention to speed up future vaccine development.

Correction to: Self-sampling for human papillomavirus testing among rural young women of KwaZulu-Natal, South Africa.

Following publication of the original article [1], one of the authors reported that his name had been spelled incorrectly. It should be Galappaththi-Arachchige, not Galapaththi-Arachchige.

Self-sampling for human papillomavirus testing among rural young women of KwaZulu-Natal, South Africa.

BACKGROUND: Cervical cancer is a major problem in women and it is important to find a suitable and acceptable screening method, especially among young in low-resource areas for future human papillomavirus (HPV) vaccine follow-up investigations. The study sought to test the acceptability of self-sampling as well as the suitability of the specimen collecting devices. METHODS: Ninety-eight young women from rural KwaZulu-Natal were enrolled between March and July 2014. Collected genital specimens were transferred to colour indicator cards for HPV detection. Participants answered a questionnaire where they described their experiences with self-sampling. Samples were tested for high-risk HPV using GP5/6+ PCR. RESULTS: Of the enrolled participants, 91 answered questionnaires and indicated that self-sampling was preferred by 51/91 (56%) women while 40/91 (44%) indicated preference for sampling by a doctor (p = 0.023). The majority, 64% were comfortable using a swab, 22% preferred a brush while 11% were comfortable with both devices. Of the 98 self-sampled specimens 61 were negative for HPV in both specimens while 37 were HPV-positive in either brush or swab. Of the 37, 26 (70%) were HPV-positive in both brush and swab (kappa = 0.743) and 11 (30%) were discordant. CONCLUSIONS: Self-sampling was acceptable to the majority of participants in this rural area. The Dacron swab was the preferred device, and can be used in combination with colour indicator cards for comfortable self-sampling, easy storage and transport of specimens plus detection.

KRAS mutation detection and prognostic potential in sporadic colorectal cancer using high-resolution melting analysis.

BACKGROUND: The development of targeted therapies has created a pressing clinical need for molecular characterisation of cancers. In this retrospective study, high-resolution melting analysis (HRMA) was validated and implemented for screening of 164 colorectal cancer (CRC) patients to detect KRAS hot-spot mutations and to evaluate its prognostic value. Direct sequencing was used to confirm and characterise HRMA results. METHODS: After establishing its sensitivity, HRMA was validated on seven cell lines and inter- and intra-variation were analysed. The prognostic value of KRAS mutations in CRC was evaluated using survival analysis. RESULTS: HRMA revealed abnormal melting patterns in 34.1% CRC samples. Kaplan-Meier survival curves revealed a significantly shorter overall (OS) and disease-free survival (DFS) for CRC patients harbouring a KRAS mutation. In the Cox regression analysis, only when colon and rectal cancer were analysed separately, KRAS mutation was a negative predictor for OS in patients with rectal cancer and DFS in those with stage II colon cancer. CONCLUSIONS: HRMA was found to be a valid screening method for KRAS mutation detection. The KRAS mutation came forward as a negative predictive factor for OS in patients with rectal cancer and for DFS in stage II colon cancer patients.

The effects of genital schistosoma haematobium on human papillomavirus and the development of cervical neoplasia after five years in a Zimbabwean population.

BACKGROUND: High-risk human papillomavirus (HPV) is responsible for cervical cancer and genital Schistosoma haematobium infection has been hypothesized to be an additional co-factor or even an independent risk factor for cervical neoplasia. The present study aimed to investigate the impact of schistosomiasis on HPV persistence and development of cell atypia in a group of rural Zimbabwean women with confirmed high-risk HPV. METHODS: A five-year follow-up was done among women previously included in a study on genital schistosomiasis. Women who had high-risk HPV at baseline were invited after 5 years for examination of cell atypia, genital schistosomiasis, and high-risk HPV. Both vaginal lavage samples (low-cost) and cervix brush samples (high-cost) were obtained for further analysis. RESULTS: Thirty-seven women were re-examined. Genital Schistosoma haematobium of a minimum of five years' duration was associated with the development high-grade squamous intraepithelial neoplasia, but not with persistent high-risk HPV. There was a high concordance between the brush and vaginal lavage (96.3% agreement, kappa 0.93); however, the number of beta-globin negative vaginal lavage samples was unacceptably high. CONCLUSIONS: Findings warrant an exploration in a larger longitudinal study where a vaginal swab should be explored.

Human papillomavirus type distribution among women with cervical pathology - a study over 4 years at Jimma Hospital, southwest Ethiopia.

Over the period 1998-2001 women attending Jimma hospital (southwest Ethiopia) with cervical dysplasia were screened for human papillomavirus (HPV), identifying a prevalence of 67.1% in this population. High-risk HPV types 16 (55.7%), 18 (8.2%), 56 (8.2%), 45 (4.1%), 39 (2.5%), 52 (1.6%), 31 (1.6%), 35 (1.6%), 58 (0.8%), 33 (0.8%), 59 (0.8%) caused severe pathology as single/multiple infection. Strategies need to be envisioned for vaccinating children, young women prior to first sexual contact and preventive screening of HPV high-risk types.

Feasibility of collecting self-sampled vaginal swabs by mail: quantity and quality of genomic DNA.

Vaginal self-sampling may be valuable as an alternative method of cervical cancer screening in areas of poor resources, to enroll women who, otherwise, would not participate in population-based cervical cancer screening and in epidemiological follow-up studies. We assessed the reliability of mailed vaginal samples by evaluating the quantity and quality of genomic DNA in the samples. Mailed swabs (n = 201) were compared with freshly collected samples (n = 200) for DNA concentration (45.1 versus 50.9 ng/microl, respectively) and purity (mean optical density [OD] 260/280 ratio 1.88 versus 1.78, respectively). A small, non-significant, decrease in DNA yield with longer transport time was noted. The DNA yield of mailed samples was significantly lower compared to fresh samples (P < 0.002), but this lower yield had little effect on polymerase chain reaction (PCR) amplification. In conclusion, the large majority of mailed self-sampled vaginal swabs resulted in DNA of adequate purity and concentration for further research.

Microsatellite instability and HPV genotype in Polish women with cervical cancer.

INTRODUCTION: Human papillomaviruses (HPVs) are associated with anogenital cancer. Little is known about the prevalence of microsatellite instability (MSI) in cervical cancer. The aim of this study was to investigate the incidence of microsatellite instability in cervical cancer and to see whether there is a relation between MSI, HPV and clinicopathological characteristics in the study population. RESULTS: Using three assays (pU1M/2R, GP5+/6+ and E6-nested multiplex PCR) HPV was detected in 110 out of 113 patients with histologically confirmed cervical cancer. The presence of MSI was investigated in 95 of the 113 cases using seven microsatellite loci. In total, 12 out of the 95 patients (12.6%) showed MSI. None of clinicopathological parameters showed a significant difference between microsatellite stable and MSI cases. CONCLUSION: In this population of Polish cervical cancer patients, 12.6% showed microsatellite instability. There was no correlation between MSI positivity and clinicopathological parameters and/or survival.

The value of human papillomavirus detection in primary cervical cancer screening.

Human papillomavirus (HPV) is present in the vast majority of high-grade gynecological abnormalities (high-grade squamous intraepithelial lesions and worse) and, therefore, HPV detection has a very high negative predictive value. Nevertheless, introduction of HPV detection into primary screening would result in large numbers of false positives: HPV positive women with normal cytology. The prevalence of HPV in women with cytologically normal smears is age-dependent as has been shown extensively. We hypothesize that women at the age of 50, who are HPV negative and have a cytologically normal smear might be encouraged to refrain from further screening. The data available from the literature on HPV prevalence in elderly women is presented. Data of cohort studies of elderly women with and without HPV infection as well as health-economical analyses to investigate the cost-effectiveness of the proposed hypothesis are still lacking.

Risk factors for cervical cancer development: what do women think?

BACKGROUND: The current cervical cancer prevention strategy is exclusively directed towards screening, without taking into account any relationship with sexual risk factors. The introduction of human papillomavirus (HPV) detection into the screening procedure implicates that we should give attention to this relationship. The aim of this study was to investigate what knowledge women have of the relation between HPV and cervical cancer. METHODS: Rather than asking about HPV specifically, we suggested 20 risk factors for the development of cervical cancer, including viral infection, and asked 73 women visiting their general practitioner, 67 women visiting a lecture on risk factors for cervical cancer and 28 female students in biomedical sciences to rate the importance of these risk factors on a scale of 1-5. RESULTS: Genetic factors were rated highest with a mean score of 4.5. Bacterial infection ranked second highest with a mean score of 3.8. Smoking ranked fourth at a mean score of 3.6, whereas viral infection shared the sixth place with number of sexual partners with a mean score of 3.4. The presence of high voltage power lines and physical activity appropriately scored the last two places at 2.4 and 2.2, respectively. Twenty-one women suggested a role for sexually transmitted agents, but only five women (3.1%) could actually pinpoint HPV. CONCLUSION: This enquiry indicates that the risk factor 'genetic factors' was over-rated, while knowledge of the most important risk factors, i.e. smoking and sexual habits and (sexually transmitted) infections, would appear to be present to a moderate level in our population. However, knowledge of the role of HPV in cervical cancer development is lacking.

Prevalence of human papillomavirus in elderly women with cervical cancer.

To investigate the relation between the prevalence of human papillomavirus (HPV) and age in cervical cancer patients, material from 93 patients with Ia-IIb cervical carcinoma was analyzed for the presence of HPV by both type-specific and general primer polymerase chain reaction. Patients were divided into 2 groups: 64 years or younger, and 65 years and older. There was no statistically significant difference in either the prevalence of HPV DNA or distribution of genotypes amongst the 2 groups. Therefore, HPV detection can be equally well used in the management and follow-up of elderly cervical cancer patients.

Human papillomavirus infection in the female population of Antwerp, Belgium: prevalence in healthy women, women with premalignant lesions and cervical cancer.

Worldwide there is a strong relation between the presence of human papillomavirus (HPV) and the development of cervical cancer. This study investigated the prevalence and genotype of HPV in women with normal smears, women with premalignant lesions and women with cervical cancer in Antwerp, Belgium. Type-specific polymerase chain reaction (PCR) for HPV types 16 and 18 and general primer PCR (GP5+/6+) was performed on DNA extracted from paraffin-embedded tissue from women with lesions or fresh material from controls. HPV was detected in 11% of controls, 61% of women with atypia, 77% of women with CIN lesions and 88% of women with cervical carcinoma (chi2 trend, 273, p<0.001). The odds ratio for high-risk HPV types was 9.3 for atypia (95%CI. 4.3-19.8), 33.6 for CIN lesions (95%CI, 19.3-58.6) and 78.8 for cervical cancer (95%CI, 39.2-158.3). In total, 19 different HPV genotypes were detected, including five low risk HPV types. Seven of the 14 high-risk HPV types were detected in cervical cancer patients. Based on our study it is suggested that a prophylactic vaccine based on a cocktail of a limited number of high-risk HPV types should be considered in order to protect most women from developing cervical cancer.

The importance of biological factors (bcl-2, bax, p53, PCNA, MI, HPV and angiogenesis) in invasive cervical cancer.

OBJECTIVE: The present study was designed to analyse the relationship between apoptosis related proteins (bcl-2 and bax), tumour suppressor protein p53, proliferation markers (PCNA and mitotic index), human papillomavirus (HPV) and angiogenesis in cervical cancer and their impact on clinical outcome. STUDY DESIGN: Tumours from 111 patients were assessed by immunohistochemistry for the expression of bcl-2, bax, p53 and PCNA, by PCR for the presence of HPV-DNA, for the quantification of the mitotic index and the microvessel density (CD 31). The results were correlated with various histopathologic characteristics and survival. RESULTS: The multiple Cox's regression analysis for overall survival of all prognostic variables gave as best model: bcl-2 (P<0.001), lymphovascular permeation (P=0.004), mitotic index (P=0.019), tumour grade (P=0.048) and FIGO stage (P=0.070). Subanalysis was performed for the patients where the lymph node status was known (n=79). Adding the lymph node status gave as best model for overall survival bcl-2 (P=0.001), lymphovascular permeation (P=0.003) and mitotic index (P=0.044). However, they hardly influenced the association. CONCLUSION: In the apoptotic pathway of cervical cancer, bcl-2 is one of most important proteins. It can probably not only mediate cell death but also regulate cell growth. A better understanding of their relations will probably provide the basis for more rational cancer therapies in the future.

Humoral immune response against proteins E6 and E7 in cervical carcinoma patients positive for human papilloma virus type 16 during treatment and follow-up.

To investigate the humoral immune response to transforming proteins E6 and E7 of human papillomavirus type 16 before and after treatment and during follow-up, consecutive serum samples from 36 cervical cancer patients whose tumours were found to contain human papillomavirus type 16 DNA by use of the polymerase chain reaction were tested using in vitro translated proteins E6 and E7 in a radioimmunoprecipitation assay and in an E7 synthetic peptide enzyme immunoassay. Antibody levels against E6 and E7 as measured by radioimmunoprecipitation assay showed a nearly identical pattern. Seronegative patients remained seronegative throughout treatment and follow-up. Seropositive patients showed either a decrease in antibody level or stable antibody levels during treatment. In contrast to patients without evidence of disease at the end of the study, the majority of patients with recurrent disease showed increasing antibody levels during the follow-up period. These results indicate that, in patients who are seropositive before treatment antibody levels against E6 and E7 of human papillomavirus type 16 after treatment are closely linked to treatment response. The use of the more sensitive radioimmunoprecipitation assay did not lead to a better correlation of antibody levels with clinical disease status of the patients than the use of the enzyme immunoassay.

A sero-epidemiological study of the relationship between sexually transmitted agents and cervical cancer in Honduras.

To investigate a possible cause-and-effect relationship between sexually transmitted diseases and cervical cancer, we performed a sero-epidemiological study on the presence of antibodies against a number of sexually transmitted agents (STAs) in patients with cervical cancer and their matched controls. In this study, we used serological techniques to investigate the presence of antibodies to cytomegalovirus, herpes simplex virus type 2, human immunodeficiency virus, Chlamydia trachomatis, Treponema pallidum and human papillomavirus (HPV) early protein E7 in sera from patients with cervical cancer, cervical intra-epithelial neoplasia and individually matched, healthy controls. The presence of antibodies to infectious agents other than HPV appeared not to be associated with risk of cervical neoplasia in either univariate or multivariate analysis. After adjustment for cytology, schooling and presence of HPV DNA in cervical scrapes, there was a significantly higher prevalence of antibodies to HPV-16 E7 protein in sera from patients with cervical cancer (OR = 3.6, 95% CI 1.0-12.9) than in healthy controls. The highest antibody prevalence was found among HPV-16 DNA-positive cervical cancer patients (33%). Our results indicate that in these study groups past infections with the STA considered seems to be of no apparent relevance for cervical carcinogenesis and that the HPV-16 anti-E7 response appears to be associated with cervical cancer.

Relation between HPV-16 serology and clinico-pathological data in cervical carcinoma patients: prognostic value of anti-E6 and/or anti-E7 antibodies.

To investigate the clinical significance of the enhanced sensitivity of antibody detection by radio immunoprecipitation assays (RIPA), using in vitro translated HPV-16 E6 and E7 proteins, over synthetic-peptide enzyme-linked immunosorbent assay (ELISA), RIPA for HPV-16 E6 and E7 were performed. The results obtained with E6 and E7 RIPA were related to clinico-pathological data from cervical carcinoma patients positive for HPV type 16 DNA in their primary tumour. The data obtained with E6 and E7 RIPA were then compared to the results obtained using the E7/6-35 synthetic-peptide ELISA. The prevalence of antibodies to E6, E7, E6 and/or E7 and E6 and E7, as determined by RIPA, was significantly higher in cervical cancer patients than in both controls and cervical intraepithelial neoplasia patients. Odds ratios, calculated for cervical carcinoma patients versus controls, ranged from 7.4 to 15.4. Antibodies to E6 and/or E7 were largely restricted to patients with HPV DNA in their primary tumour. Analysis of the relation between prevalence of antibodies to E6 and E7 and clinico-pathological parameters was limited to 85 patients positive for HPV-16 DNA. The strongest relation with clinico-pathological data, such as lesion size, lymph node involvement, and prognosis, was found for E7 synthetic-peptide ELISA, whereas E6 and E7 RIPA did not reach significance. The significance of these findings is discussed.

Detection of HPV-16 DNA by PCR in histologically cancer free lymph nodes from patients with cervical cancer.

The prognostic value of detection of human papillomavirus (HPV) type 16 DNA in histologically cancer free lymph nodes was assessed in left obturator lymph nodes from cervical cancer patients with HPV-16 positive primary tumours. HPV-16 DNA was detected by polymerase chain reaction in 12 of 35 patients with histologically cancer free lymph nodes. Of these 12 patients, only one developed a recurrence, suggesting HPV-16 DNA detection in cancer free lymph nodes has no prognostic value.

Comprehensive study of several general and type-specific primer pairs for detection of human papillomavirus DNA by PCR in paraffin-embedded cervical carcinomas.

We have compared the efficacies of three general primer pairs for the detection of human papillomavirus (HPV) DNA in formaldehyde-fixed paraffin-embedded carcinomas. The use of these primer pairs leads to underestimates of the HPV prevalence (GP5/6, 61.1%; CPI/IIG, 57.4%; MY09/11, 46.9%; combined, 72.8%). The efficacy of each primer pair seemed to be inversely correlated to the length of the amplimer produced. By using newly developed type-specific primer pairs (amplimer length, approximately 100 bp), an increase in HPV DNA detection (87.6%) was found.