The Incidence of Human Papillomavirus in Tanzanian Adolescent Girls Before Reported Sexual Debut

Approaches to Estimating Clearance Rates for Human Papillomavirus Groupings: A Systematic Review and Real Data Examples

INTRODUCTION

Approaches to estimating clearance rates, an important metric of human papillomavirus (HPV) clearance, for HPV groupings differ between studies. We aimed to identify the approaches used in the literature for estimating grouped HPV clearance rates. We investigated whether these approaches resulted in different estimations, using data from existing studies.

METHODS

In this systematic review, we included articles that reported clearance rates of HPV groupings. We identified approaches to data in the HAVANA cohort, comprising adolescent girls, and the H2M cohort, comprising men who have sex with men. We estimated clearance rates for six HPV groupings (bivalent-, quadrivalent- and nonavalent vaccine-related, and low-risk, high-risk, and any HPV).

RESULTS

From 26 articles, we identified 54 theoretically possible approaches to estimating clearance rates. These approaches varied regarding definitions of clearance events and person-time, and prevalence or incidence of infections included in the analysis. Applying the nine most-used approaches to the HAVANA ( n = 1,394) and H2M ( n = 745) cohorts demonstrated strong variation in clearance rate estimates depending on the approach used. For example, for grouped high-risk HPV in the H2M cohort, clearance rates ranged from 52.4 to 120.0 clearances/1000 person-months. Clearance rates also varied in the HAVANA cohort, but differences were less pronounced, ranging from 24.1 to 57.7 clearances/1000 person-months.

CONCLUSIONS

Varied approaches from the literature for estimating clearance rates of HPV groupings yielded different clearance rate estimates in our data examples. Estimates also varied between study populations. We advise clear reporting of methodology and urge caution in comparing clearance rates between studies.

Prevalence of vaginal HPV infection among adolescent and early adult girls in Jos, North-Central Nigeria

Purpose

Knowledge of the prevalence of HPV infection among adolescent and early adult girls is essential to determining the best age for the introduction of HPV vaccine, monitoring vaccine efficacy, and giving insight into determinants of persistent high-risk HPV infection, a necessary cause of cervical cancer. Yet, there have been limited studies of HPV infection among adolescent and early adult girls in low-and-middle-income countries.

Methods

In this cross-sectional study, we randomly selected 205 girls, aged 9–20 years, from 10 schools in central Nigeria. We obtained informed consent and assent, collected data, and trained participants to self-collect vaginal samples using swab stick. We genotyped HPV using SPF₁₀-DEIA/LiPA₂₅ and analyzed data using Stata 14®.

Results

The mean (SD) age of the girls was 14.9 (2.3) years. We found HPV in 13.2% of vaginal swabs. The earliest age at which anyHPV and hrHPV infections were detected was 10 and 12 years respectively. The prevalence of any HPV peaked at 16 and 17 years, hrHPV at 16 years, lrHPV at 17 and 18 years and multiple hrHPV 18 years of age. The prevalence of hrHPV infection was 1.5% among the 9–12 years age group, 2.9% among 13–16 years and 3.4% among 17–20 years old. The commonest hrHPV types detected were 52 (3.9%), 18 (1.5%) and 51 (2.4%). The most common lrHPV types was 6 (2.9%).

Conclusion

The prevalence of HPV infection in these urbanized young girls in Nigeria is high and commences after 9 years of age. HPV vaccination in this population should start at 9 years of age or younger to prevent the establishment of persistent HPV infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07215-7.

The prevalence of HPV was 13.2% among adolescent girls in Jos, North-Central Nigeria.

The earliest age at vaginal HPV infection was 11 years of age.

The most predominant hrHPV type in vaginal swab was HPV 52.

These findings point to the need for introduction of HPV vaccine starting at 9 years of age among girls in Nigeria to give maximum protection.

Adolescent Health Series: HPV infection and vaccination in sub-Saharan Africa: 10 years of research in Tanzanian female adolescents - narrative review

Cervical cancer is the leading cause of cancer-related morbidity and mortality in many sub-Saharan African (SSA) countries, including Tanzania. Most cervical cancer cases worldwide are attributable to infection of the cervix with Human Papillomavirus (HPV), a vaccine-preventable sexually transmitted infection (STI). Over the past 10 years, we have conducted a programme of HPV research in pre-adolescents and adolescents in Mwanza, the second-largest city in Tanzania, which is situated in a malaria-endemic region. In this narrative review article, we summarise the contribution of our work, alongside work of others, to improve the understanding of HPV epidemiology in SSA and development of setting-appropriate, evidence-based intervention strategies. We present evidence for very high prevalence and incidence of HPV infection among female SSA adolescents around the time of sexual debut, describe risk factors for HPV acquisition, and discuss associations between HPV, HIV and other STIs, which are also highly prevalent within this population. We summarise findings from early clinical trials of HPV vaccines in SSA, the first of which was an immunogenicity and safety trial conducted in Mwanza, Tanzania, and Dakar, Senegal. Within the trial, we evaluated for the first time the potential impact of malaria and helminth infection on vaccine-induced antibody responses in Tanzanian girls. We describe research evaluating optimal HPV vaccine delivery strategies within this setting, perceived requirements for and barriers to vaccine implementation among key informants from LMIC, vaccine acceptability among girls and parents, and opportunities for co-delivery of interventions alongside HPV vaccination to an adolescent population. Finally, we discuss country-level barriers to vaccine uptake in LMIC, and ongoing studies in Tanzania and other SSA countries of reduced-dose HPV vaccination schedules that may alleviate cost and logistical barriers to vaccine implementation.

Incident detection of human papillomavirus - a prospective follow-up study among Tanzanian women with a focus on HIV status

BACKGROUND

The causative role of human papillomavirus (HPV) in cervical carcinogenesis is well established; however, prospective studies examining high-risk(HR)-HPV acquisition among adult women in HIV-prevalent settings are limited.

METHODS

We conducted a prospective study among women (25-60 years) attending cervical cancer screening in Tanzania. Cervical specimens obtained at enrolment and follow-up were tested for HPV. Participants were interviewed on lifestyle and tested for HIV.

RESULTS

Among 3805 eligible women, 3074 (80.8%) attended follow-up (median time between the 2 examinations, 17.3 months); 307 had missing HPV results at enrolment or follow-up, leaving 2767 study participants. Among 2253 women initially HR-HPV negative, 184 acquired HR-HPV-incidence: 54.5 per 1000 person-years (95% CI:47.1-62.9); among HIV-positive women 75.2 per 1000 person-years (95% CI:54.5-103.7), HIV-negative 50.9 per 1000 person-years (95% CI:43.3-60.0). HPV52 and HPV16 were the most frequently acquired types. In multivariable regression analysis, HIV positivity, low CD4 count, younger age, and multiple sexual partners were associated with increased odds of HPV acquisition.

CONCLUSION

HPV acquisition was higher among HIV-positive than HIV-negative women, especially women with low CD4 counts. Improvement of immune status among HIV-positives may decrease HPV acquisition. Nonavalent HPV vaccination should be considered given the pattern of HR-HPV types acquired.

A dose-reduction HPV vaccine immunobridging trial of two HPV vaccines among adolescent girls in Tanzania (the DoRIS trial) - Study protocol for a randomised controlled trial

BACKGROUND

Human papillomavirus (HPV) infection is the primary cause of cervical cancer. In 2018, the World Health Organization (WHO) Director General announced his commitment to eliminate cervical cancer, with HPV vaccination as a priority. However, the costs of setting up a multi-dose HPV vaccination programme remain a barrier to its introduction.

METHODS/DESIGN

We are conducting a randomised-controlled trial of reduced dose schedules of HPV vaccine in Tanzania to establish whether a single dose produces immune responses that will be effective in preventing cervical cancer. 930 girls aged 9-14 years in Mwanza, Tanzania, were randomised to one of 6 arms, comprising 3 different dose schedules of the 2-valent (Cervarix) and 9-valent (Gardasil-9) HPV vaccines: 3 doses; 2 doses given 6 months apart; or a single dose. All participants will be followed for 36 months; those in the 1 and 2 dose arms will be followed for 60 months. Trial outcomes focus on vaccine immune responses including HPV 16/18-specific antibody levels, antibody avidity, and memory B cell responses. Results will be immunobridged to historical cohorts of girls and young women in whom efficacy has been demonstrated.

DISCUSSION

This is the first randomised trial of the single dose HPV vaccine schedule in the target age group. The trial will allow us to examine the quality and durability of immune responses of reduced dose schedules in a population with high burden of malaria and other infections that may affect vaccine immune responses. Initial results (24 months) are expected to be published in early 2021.

Human papilloma viruses infection among adolescent females perinatally infected with HIV in Côte d'Ivoire

BACKGROUND

Cervical cancer prevention strategies recommend human papilloma virus (HPV) vaccination for female adolescents prior to their sexual debut. While HIV is a major risk factor for HPV infection in women of childbearing age, its prevalence among HIV-infected adolescent female is mostly unknown. This study aimed to describe the HPV prevalence and correlates among perinatally HIV-infected adolescent females prior to HPV immunisation.

METHODS

A cross-sectional survey was conducted from January to June 2016, in the four major paediatric HIV clinics of Abidjan, Côte d'Ivoire. All HIV-infected females aged 11-16 years were approached to participate in the study. A questionnaire assessing sexual behaviours and genital hygiene practices was administered to participants completed with a systematic vaginal swab collection. HPV genotyping was performed using the Anyplex II HPV28 Detection (Seegene). A logistic regression analysis was performed to identify factors associated with the presence of HPV infection. HPV immunisation was proposed free of charge to all participants.

RESULTS

A total of 250 participants were included, with a median age of 13 years (IQR 11-14). Among them, 237 (94.8%) were on antiretroviral treatment with a median CD4 count of 660 (IQR 439-914) cells/mm³. The overall prevalence of at least one HPV was 3.6% (95% CI 1.6 to 6.7) and the prevalence of at least one carcinogenic HPV was 2.8% (95% CI 0.7 to 4.8). Vaginal cleansing was reported by 75 (30%) of participants, with a median age at initiation of 12 years (IQR 10-13). Sexual activity was self-reported by 12 (4.8%) participants with a median age at sexual debut of 11 years (IQR 10-14). HPV infection was associated with vaginal cleansing (adjusted OR=7.0 (95% CI 1.4 to 31.6)).

CONCLUSION

The reported low prevalence of carcinogenic HPV infections supports the appropriateness of HPV immunisation in this population. The reported association between cleansing practices and HPV infection deserves further prospective longitudinal studies.

Estimating incidence rates of grouped HPV types: A systematic review and comparison of the impact of different epidemiological assumptions

BACKGROUND

Some studies on human papillomavirus (HPV) provide not only type-specific incidence rates (IR), but also IRs of HPV groupings (e.g. the nonavalent grouping). We made an inventory of the different approaches used to calculate such IRs and assessed their impact on the estimated IRs of HPV groupings.

METHODS

We performed a systematic review assessing all approaches used in literature to estimate IRs. Subsequently we applied these approaches to data of a Dutch cohort study on HPV in men who have sex with men (H2M). IRs were estimated for six different HPV groupings.

RESULTS

The systematic review yielded six different approaches (A-F) for estimating the IRs, varying in exclusion criteria at baseline, and the definitions of an incident event and person-time. Applying these approaches to the H2M dataset (n = 749), we found differences in the number of participants at risk, number of incidents events, person-time, and IR. For example, for the nonavalent grouping, depending on the approach chosen, the IR varied between 3.09 and 6.54 per 100 person-months.

CONCLUSION

In published studies different epidemiological assumptions are used to estimate IRs of grouped HPV types, leading to widely differing estimates of IRs. IRs between different studies may therefore not be comparable.

Cervical cancer in Tanzania: A systematic review of current challenges in six domains

Cervical cancer is the most common cancer in Tanzania. After excluding human immunodeficiency virus, lower respiratory infections, malaria, diarrheal diseases, and tuberculosis, cervical cancer kills more women than any other form of illness in the country. Unfortunately, Tanzania has a low doctor-to-patient ratio (1:50,000) and nearly 7000 women die each year from this disease. The clinical problem is further magnified by the country's lack of resources and prevailing poverty, sporadic cervical cancer screening, prevalence of high-risk oncogenic human papillomavirus subtypes, and relatively high rates of human immunodeficiency virus co-infection. In recent years, addressing the cervical cancer problem has become a priority for the Tanzanian government. In this systematic review of 39 peer-reviewed publications that appeared in the PubMed/MEDLINE (NCBI) database from 2013 to 2018, we synthesize the growing body of literature to capture current trends in Tanzania's evolving cervical cancer landscape. Six domains were identified, including risk factors, primary prevention, barriers to screening, treatment, healthcare worker education, and sustainability. In addition to traditional risk factors associated with sexual behavior, acetowhite changes observed during visual inspection of the cervix with acetic acid, lower education, rural setting, and HIV positivity also have a noteworthy clinical impact.

HPV prevalence around the time of sexual debut in adolescent girls in Tanzania

OBJECTIVES

Cervical cancer is the leading cause of cancer-related mortality among women in sub-Saharan Africa (SSA). Data on human papillomavirus (HPV) epidemiology in adolescent girls in SSA are essential to inform HPV vaccine policy recommendations for cervical cancer prevention. We assessed the burden of HPV infection, and risk factors for infection, among adolescent girls around the time of sexual debut.

METHODS

Cross-sectional study of secondary school girls aged 17-18 years in Tanzania. Consenting participants provided samples for HPV and STI testing. Vaginal swabs were tested for 37 HPV genotypes by Roche Linear Array. Logistic regression was used to identify factors associated with HPV infection. Y chromosome was tested as a marker of recent condomless sex.

RESULTS

163/385 girls (42.3%) reported previous penetrative sex. HPV was detected in 125/385 (32.5%) girls, including 84/163 (51.5%) girls reporting previous sex and 41/222 (18.5%) reporting no previous sex. High-risk (HR) genotypes were detected in 70/125 (56.0%) girls with HPV infection. The most common HR genotype was HPV-16 (15/385; 3.9%). The prevalence of other HR HPV vaccine genotypes was between 0.8% and 3.1%. Among 186 girls who reported no previous sex, were negative for Y chromosome, and had no STI, 32 (17%) had detectable HPV. Lactobacillus sp and bacterial vaginosis-associated bacteria were negatively and positively associated, respectively, with HPV.

CONCLUSIONS

HPV prevalence among adolescent girls around the time of sexual debut was high. However, prevalence of most vaccine genotypes was low, indicating that extending the age range of HPV vaccination in this region may be cost-effective.

Acquisition, Persistence, and Clearance of Human Papillomavirus Infection Among Male Virgins Residing in Brazil, Mexico, and the United States

Background

Little is known about the natural history of human papillomavirus (HPV) infection in male virgins. This study estimated the incidence and clearance of genital HPV infection and the factors associated with these measures among men who denied at baseline ever having penetrative sex.

Methods

A cohort of 4123 men residing in Brazil, Mexico, and the United States were followed every 6 months for up to 10 visits. Genital exfoliated cells were collected and genotyped for 36 HPV types. Eighty-seven men were classified as virgins and included for analysis. Cox proportional hazards models identified factors associated with the incidence and clearance of genital HPV infection.

Results

The incidence rates for any HPV infection among virgins who did and those who did not initiate sex during follow-up were 26.2 and 14.6 cases/1000 person-months, respectively. After penetrative sex initiation, 45.5% of men acquired HPV within 24 months. Younger age, current smoking, no recent female sex partners, and prevalent HPV infection were associated with high-risk HPV clearance.

Conclusion

Virgins who did not initiate sex during follow-up still acquired HPV infection, possibly through nonpenetrative sexual contact. Further prospective cohort studies are needed to better understand factors associated with HPV acquisition and clearance in male virgins and recent nonvirgins.

Cervical cancer in sub-Saharan Africa: a preventable noncommunicable disease

INTRODUCTION

Infections caused by high-risk human papillomavirus (HPV) are responsible for 7.7% of cancers in developing countries, mainly cervical cancer. This disease is steadily increasing in sub-Saharan Africa, with more than 75,000 new cases and 50,000 deaths yearly, further increased by HIV infection. Areas covered: The current status of cervical cancer associated with HPV in sub-Saharan Africa has been systematically revised. The main issues discussed here are related to the public health burden of cervical cancer in sub-Saharan Africa and predictions for the coming decades, including molecular epidemiology and determinants of HPV infection in Africa, and promising prevention measures currently being evaluated in Africa. Expert commentary: By the year 2030, cervical cancer will kill more than 443,000 women yearly worldwide, most of them in sub-Saharan Africa. The increase in the incidence of cervical cancer in Africa could counteract the progress made by African women in reducing maternal mortality and longevity. Nevertheless, cervical cancer is a potentially preventable noncommunicable disease, and intervention strategies to eliminate cervical cancer as a public health concern should be urgently implemented.

Associations of Human Papillomavirus (HPV) genotypes with high-grade cervical neoplasia (CIN2+) in a cohort of women living with HIV in Burkina Faso and South Africa

Objective

To describe associations of high-risk human papillomavirus (HR-HPV) with high-grade cervical intraepithelial neoplasia (CIN2+) in women living with HIV (WLHIV) in Burkina Faso (BF) and South Africa (SA).

Methods

Prospective cohort of WLHIV attending HIV outpatient clinics and treatment centres. Recruitment was stratified by ART status. Cervical HPV genotyping using INNO-LiPA and histological assessment of 4-quadrant cervical biopsies at enrolment and 16 months later.

Results

Among women with CIN2+ at baseline, the prevalence of any HR-HPV genotypes included in the bi/quadrivalent (HPV16/18) or nonavalent (HPV16/18/31/35/45/52/58) HPV vaccines ranged from 37% to 90%. HPV58 was most strongly associated with CIN2+ (aOR = 5.40, 95%CI: 2.77–10.53). At 16-months follow-up, persistence of any HR-HPV was strongly associated with incident CIN2+ (aOR = 7.90, 95%CI: 3.11–20.07), as was persistence of HPV16/18 (aOR = 5.25, 95%CI: 2.14–12.91) and the additional HR types in the nonavalent vaccine (aOR = 3.23, 95%CI: 1.23–8.54).

Conclusion

HR-HPV persistence is very common among African WLHIV and is linked to incident CIN2+. HPV vaccines could prevent between 37–90% of CIN2+ among African WLHIV.