A Nationwide Evaluation of the Prevalence of Human Papillomavirus in Brazil (POP-Brazil Study): Protocol for Data Quality Assurance and Control.

BACKGROUND: The credibility of a study and its internal and external validity depend crucially on the quality of the data produced. An in-depth knowledge of quality control processes is essential as large and integrative epidemiological studies are increasingly prioritized. OBJECTIVE: This study aimed to describe the stages of quality control in the POP-Brazil study and to present an analysis of the quality indicators. METHODS: Quality assurance and control were initiated with the planning of this nationwide, multicentric study and continued through the development of the project. All quality control protocol strategies, such as training, protocol implementation, audits, and inspection, were discussed one by one. We highlight the importance of conducting a pilot study that provides the researcher the opportunity to refine or modify the research methodology and validating the results through double data entry, test-retest, and analysis of nonresponse rates. RESULTS: This cross-sectional, nationwide, multicentric study recruited 8628 sexually active young adults (16-25 years old) in 119 public health units between September 2016 and November 2017. The Human Research Ethics Committee of the Moinhos de Vento Hospital approved this project. CONCLUSIONS: Quality control processes are a continuum, not restricted to a single event, and are fundamental to the success of data integrity and the minimization of bias in epidemiological studies. The quality control steps described can be used as a guide to implement evidence-based, valid, reliable, and useful procedures in most observational studies to ensure data integrity. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/31365.

Behavioral factors associated with multiple-type HPV genital infections: data from a cross-sectional study in young women in Brazil.

OBJECTIVES: To investigate the pattern of multiple human papillomavirus (HPV) infections and associated factors in young women who access the Brazilian public health care system to better understand the characteristics of multiple HPV infections, a critical issue in this era of multivalent vaccines. METHODS: This was a cross-sectional, multicenter study with sexually active unvaccinated women (16-25 years old) from 119 primary Brazilian healthcare centers between September 2016 and November 2017. Cervical samples were collected by trained health professionals, and HPV detection was performed in a central laboratory by Linear Array. RESULTS: Of the 5268 women, 33.00% (95% CI 31.07-34.92) had multiple infections. At least one type of high-risk HPV was present in 85.50% of all multiple infections. All HPV types were detected more frequently in association with other types than alone. Young individuals who were single or in a casual relationship and those who had more than one sexual partner in the past year were more likely to have multiple infections. CONCLUSIONS: In this work, a high rate of multiple HPV infections among unvaccinated young adults tended to increase due to certain risk factors. Such data can provide insight for decision makers in the development of public policies regarding HPV prevention.

Understanding the characteristics of multiple infections is critical in the era of HPV multivalent vaccines for the prevention of cervical carcinomas. Therefore, in this cross-sectional study, we aimed to investigate the pattern of multiple HPV infections and associated factors in 5,268 sexually active unvaccinated women (16­25 years old) who access the Brazilian public health care system. Cervical samples were collected by trained health professionals, and HPV detection was performed in a central laboratory by Linear Array. A total of 33.00% (95% CI 31.07­34.92) had multiple infections (60.43% of the HPV-positive sample). The number of HPV types in a multiple infection ranged from 2 to 14 different types. The viral types more frequently identified were HPV 16 and 52. All HPV types were detected more frequently in association with other types than alone. The incidence of multiple infections was 1.29 times higher in single than in married or cohabitating participants. Women who had two or more partners in the last year also had higher rates of multiple infections than those who had fewer than two sexual partners. In conclusion, a high prevalence of multiple infections prior to the national HPV immunization program was observed, especially with the increase in less safe behavior factors.

Study protocol: epidemiological and clinical characteristics of acute viral hepatitis in Brazilian health services.

INTRODUCTION: Acute viral hepatitis is a disease of great clinical importance. This study proposes actions to better characterise cases of acute hepatitis in Brazil and to provide relevant information to institutionalised health policies within the Unified Health System. Available data on acute hepatitis in Brazil need to be re-evaluated regarding the different hepatotropic agent (hepatitis A to E virus) frequencies, as well as other agents that can cause similar clinical conditions, such as Herpes Simplex Virus 1 and 2(HSV1, HSV2), Varicella Zoster Virus (VZV), Cytomegalovirus (CMV), Epstein Barr Virus (EBV), Human Herpes Virus 6 and 7 (HHV6, HHV7), arbovirus (yellow fever, dengue, chikungunya, Zika), parvovirus B19, adenovirus, parechovirus, enterovirus, HIV, leptospirosis, toxoplasmosis and syphilis, in addition to autoimmune hepatitis. In this context, the primary aim of this study is the clinical-epidemiological and molecular characterisation of acute viral hepatitis in Brazilian health services from all geographical regions of the country. The present article describes the study protocol. METHODS AND ANALYSIS: This study will evaluate 2280 patients with symptoms and/or signs suggestive of acute liver disease in Brazilian health institutions in all five geographic Brazilian regions. Demographic, epidemiological and clinical data will be collected, as well as blood samples to be analysed at Hospital Israelita Albert Einstein Clinical Laboratory. ETHICS AND DISSEMINATION: Ethics approval was obtained at the national research ethics committee (Conselho Nacional de Ética em Pesquisa- CONEP-CAAE 00952818.4.1001.0071) and at all participating sites. Results will be published in journals and presented at scientific meetings.

Effectiveness of a universal vaccination program with an HPV quadrivalent vaccine in young Brazilian women.

We examined human papillomavirus (HPV) vaccine effectiveness in a nationwide sample of women aged 16 to 25 years who utilized the public health system in Brazil. This was a cross-sectional, multicentric survey conducted between September 2016 and November 2017 (POP-Brazil Study). A total of 5,945 young adult women were recruited from 119 public primary care units from all 27 federative units of Brazil by trained health professionals. The participants participated in a face-to-face interview and provided biological samples for genital HPV analysis. HPV genotyping was performed using a Linear Array HPV genotyping test in a central laboratory. Sampling weights were applied to the data. Overall, 11.92% (95% CI 10.65, 13.20) of the participants reported having been vaccinated. The frequency of vaccination was highest in 16- to 17-year-old women, with a decreasing vaccination rate with increasing age, and vaccinated women were more likely to belong to the high socioeconomic status group. The use of a quadrivalent vaccine decreased the HPV types 6, 11, 16, and 18 by 56.78%, from 15.64% in unvaccinated women to 6.76% in vaccinated women (P < 0.01), even after adjustment for age. Those who received the vaccine had lower HPV 16 (2.34% in vaccinated vs 8.91% in unvaccinated, P < 0.01) and 6 rates (2.06% vs 5.77%, P < 0.01). Additionally, a higher rate of high-risk HPV types other than HPV 16 and 18 (40.47% in vaccinated vs 32.63% in unvaccinated, P < 0.01) was observed. In conclusion, the results of this study support the effectiveness of HPV vaccination in Brazil. Continuous surveillance must be assured to monitor the HPV infection rate in the vaccination era.

Sexual behavior and its association with persistent oral lesions: analysis of the POP-Brazil study.

OBJECTIVES: To investigate whether the presence of persistent self-reported oral lesions (PSOLs) is associated with sexual behaviors and with the presence of sexually transmitted infections (STIs) in individuals aged 16-25 years in the state capitals of Brazil. MATERIALS AND METHODS: Data from the POP-Brazil study were analyzed. An association analysis was performed by Poisson regression with the presence of PSOLs as the outcome. The exposure variables were the age at first sexual intercourse, the number of partners, oral sex practice, and aspects of condom use for model 1, and the presence of a self-reported STI or a positive rapid test for HIV/syphilis and the presence of genital human papillomavirus (HPV) for model 2. The results were adjusted for socioeconomic variables. RESULTS: The prevalence of PSOLs was 76% higher among individuals who had two or more sexual partners in the past year (p = 0.046) and 68% higher in those who reported not using condoms for contraception (p = 0.032). The group with HIV/syphilis or self-reported STI had a 140% higher PSOL prevalence (p = 0.003). CONCLUSIONS: The self-report of oral lesions in adolescents and young adults may suggest risky sexual behavior and the presence of STI. CLINICAL RELEVANCE: It is necessary to contextualize the reality of the young person to optimize oral health care.

Sex differences in the prevalence and determinants of HPV-related external genital lesions in young adults: a national cross-sectional survey in Brazil.

BACKGROUND: External genital lesions (EGL) are the most common sexually transmitted infections (STIs). We aimed to evaluate the prevalence, determinants and sex differences in EGL among young adults from Brazil. METHODS: Overall, 7694 participants (aged 16 to 25 years) underwent an interview, genital examination and sampling for HPV genotyping. RESULTS: The prevalence of EGL was 4.08% (234) and is more frequent in men (5.72%) than women (2.31%) (p <  0.001). Genital lesions were significantly associated with male sex, infection by high-risk and multiple HPV types, having more than two sexual partners in the last year, smoking status and the presence of other STI. While alcohol use was associated with a higher prevalence of EGL in women, same-sex sexual relationship increase the prevalence in men. In the EGL group, 67.79% (p = 0.032) were positive for HPV infection and the types HPV6 and HPV11 were the most prevalent ones. CONCLUSION: The prevalence of EGL in young adults was consistently high, and most cases were associated with genital HPV infection and STIs. Although men have a higher prevalence, both sexes share most genital lesion determinants. The promotion of sexual education and vaccination especially focus in young men, who are usually outside the targets of primary health care programmes, can prevent EGL in Brazilian young adults.

STOP HPV study protocol: a nationwide case-control study of the association between oropharyngeal cancer and human papillomavirus (HPV) infection in Brazil.

INTRODUCTION: Human papillomavirus (HPV) is the most common sexually transmitted infection and is associated with several types of cancer. The number of cases of HPV-associated head and neck squamous cell carcinomas (HNSCCs), especially oropharyngeal carcinomas, has increased significantly in recent years despite decreased tobacco smoking rates. Currently, no data concerning the risk factors and prevalence of HPV in HNSCC patients in all regions of Brazil are available, making it difficult to promote advances in this field of public health. Therefore, our goal is to determine the impact of infection by HPV, including HPVs with different genotypes, on head and neck cancer and the risk factors associated with the development of head and neck cancer in all regions of Brazil. METHODS AND ANALYSIS: This is a case-control study that will include 622 patients and 622 controls from all regions of Brazil. A questionnaire will be applied to gather information on sociodemographic, behavioural and health factors. Oral, cervical or penile/scrotal, and anal specimens and serum samples will be collected from all participants. Formalin-fixed paraffin-embedded tissue from tumour biopsies will be analysed only in the case group. Molecular and serological analyses will be performed to evaluate the presence and role of HPV in the development of head and neck cancer. ETHICS AND DISSEMINATION: This project was approved by the research ethical committee of the proposing institution (Hospital Moinhos de Vento, number 2.852.060). Ethical approval from the collaborators is currently under evaluation and is not yet complete. The results of this study will be presented at meetings with the Brazilian Ministry of Health through technical reports and to the scientific community at national and international events, with subsequent publication of scientific articles.

Adequacy of prenatal care, diagnosis and treatment of syphilis in pregnancy: a study with open data from Brazilian state capitals / Adequação de atendimento pré-natal, diagnóstico e tratamento da sífilis gestacional: um estudo com dados abertos de capitais brasileiras / Adecuación de la atención prenatal, diagnóstico y tratamiento de la sífilis en el embarazo: un estudio con datos abiertos en siete capitales brasileñas

Abstract: To assess the adequacy of prenatal care offered in the Brazilian capital cities and the diagnosis of gestational syphilis through public data from health information systems. The modified Kotelchuck index for adequacy of prenatal care was built using Brazilian Information System on Live Births (SINASC) data. Data on gestational syphilis, congenital syphilis, estimated population coverage by the Family Health Strategy (FHS), the Municipal Human Development Index (MHDI) and data from National Program for Access and Quality Improvement in Primary Care (PMAQ-AB) were accessed in public sites. The profile of pregnant women associated with inadequate care was assessed by logistic regression. In total, 685,286 births were analyzed. Only 2.3% of women did not attend prenatal appointments. The mean adequacy was 79.7%. No correlation was found between adequacy of prenatal care and FHS coverage (p = 0.172), but a positive correlation was found with the MHDI (p < 0.001). Inadequacy of prenatal care was associated with age below 20 years old, schooling less than 4 years, non-white skin color and not having a partner. Among the congenital syphilis cases, 17.2% of mothers did not attend prenatal care. Gestational syphilis more often affected vulnerable women, including a higher proportion of adolescents, women with low schooling, and women of non-white color. The PMAQ-AB showed a median availability of 27.3% for syphilis rapid tests, 67.7% for benzathine penicillin, and 86.7% for benzathine penicillin administration by health teams. The use of public data showed a low adequacy of prenatal care in Brazilian capitals, denoting insufficient quality for the diagnosis and treatment of gestational syphilis, despite the availability of supplies. Continuous monitoring can be carried out using public data, indicating to local strategies to eliminate congenital syphilis.

Resumo: O estudo buscou avaliar a adequação do atendimento pré-natal oferecido nas capitais brasileiras e o diagnóstico da sífilis gestacional através de dados públicos dos sistemas de informação de saúde. Foi construído o indicador de Kotelchuck modificado para adequação do atendimento pré-natal, usando dados do Sistema de Informações sobre Nascidos Vivos (SINASC). Foram acessados em sites públicos os dados sobre sífilis gestacional, sífilis congênita, estimativa da cobertura populacional pela Estratégia Saúde da Família (ESF), Índice de Desenvolvimento Humano (IDH) municipal e dados do Programa Nacional de Melhoria do Acesso e da Qualidade da Atenção Básica (PMAQ-AB). O perfil das gestantes associado ao atendimento inadequado foi avaliado com base na regressão logística. Foram analisados um total de 685.286 nascimentos. Apenas 2,3% das mulheres não receberam atendimento pré-natal. A taxa média de adequação foi de 79,7%. Não foi encontrada correlação entre a adequação do pré-natal e a cobertura pela ESF (p = 0,172), mas houve correlação com o IDH municipal (p < 0,001). A inadequação da assistência pré-natal mostrou associação com a idade < 20 anos, escolaridade < 4 anos, raça/cor não-branca e situação conjugal sem companheiro. Entre os casos de sífilis congênita, 17,2% das mães não haviam recebido atendimento pré-natal, e a sífilis gestacional afetava mais as gestantes vulneráveis, incluindo uma proporção maior de adolescentes, mulheres com baixa escolaridade e mulheres não brancas. O PMAQ-AB mostrou uma disponibilidade mediana de 27,3% de testes rápidos para sífilis, 67,7% para penicilina benzatina e 86,7% para administração de penicilina benzatina pela equipe de saúde. O uso de dados públicos revelou baixa adequação do atendimento pré-natal nas capitais brasileiras, denotando qualidade insuficiente para o diagnóstico e tratamento da sífilis gestacional, apesar da disponibilidade de insumos. O monitoramento contínuo pode ser realizado com o uso de dados públicos, indicando estratégias locais para eliminar a sífilis congênita.

Resumen: El objetivo de este trabajo ha sido evaluar la adecuación de la atención prenatal que se ofreció en capitales brasileñas, y el diagnóstico de sífilis gestacional, mediante datos públicos de los sistemas de información de salud. El indicador modificado de Kotelchuck para la adecuación de la atención prenatal se construyó usando datos del Sistema de Información sobre Nacidos Vivos (SINASC). La información sobre sífilis gestacional, sífilis congénita, así como la cobertura de población estimada por la Estrategia Salud de Familia (ESF), Índice de Desarrollo Humano (IDH) municipal y datos del Programa Nacional para el Acceso Mejorado y Calidad de la Atención Básica (PMAQ-AB) se recabaron de sitios web públicos. El perfil de las mujeres embarazadas asociado con el cuidado inadecuado fue evaluado mediante regresión logística. En total, se analizaron 685.286 nacimientos. Solamente un 2,3% de las mujeres no atendieron a citas prenatales. La adecuación media fue de un 79,7%. No se encontró correlación entre la adecuación del cuidado prenatal y la cobertura de la ESF (p = 0,172), pero se encontró una correlación positiva con el MHDI (p < 0,001). La inadecuación del cuidado prenatal estuvo asociada con una edad < 20 años, escolaridad < 4 años, raza no blanca y no tener pareja. Entre los casos de sífilis congénita, un 17,2% de las madres no asistieron a la atención prenatal. La sífilis gestacional afectó más a menudo a las mujeres vulnerables, incluyendo una más alta proporción de adolescentes, mujeres con baja escolaridad, y mujeres de color no blanco. La PMAQ-AB mostró un promedio de disponibilidad de un 27,3%, en el caso de test rápidos de sífilis, un 67,7% para la penicilina benzatínica, y un 86,7% para la administración penicilina benzatínica por equipos de salud. El uso de los datos públicos mostró una baja adecuación del cuidado prenatal en capitales brasileñas, denotando una insuficiente calidad para el diagnóstico y tratamiento de la sífilis gestacional, a pesar de la disponibilidad de suministros. La supervisión continua se puede llevar a cabo usando datos públicos, apuntando a estrategias locales para eliminar la sífilis congénita.

Evaluating sexual health in sex workers and men who have sex with men: the SMESH cross-sectional protocol study.

INTRODUCTION: Human papillomavirus (HPV) infection is transmitted through skin-to-skin contact, and vaginal and anal sex are the most common transmission routes. Sex workers and men who have sex with men (MSM) are more exposed to the virus, and therefore, a higher frequency of this infection would be expected. The prevalence of HPV infection types and the forms and factors of transmission must be investigated to control infection-related outcomes. This protocol study will be the first nationwide study with a uniform methodology to evaluate HPV prevalence of and infection types among sex workers and MSM in Brazil. METHODS AND ANALYSIS: This multicentre cross-sectional study will be conducted with a respondent-driven sampling method to recruit 1174 sex workers and 1198 MSM from all regions of Brazil. The study will consist of preliminary interviews to verify the eligibility criteria and characterise the network size as well as a second questionnaire to obtain sociodemographic, behavioural and sexual information. Specimens from the oral cavity and anal and cervical or penile/scrotal sites will be collected. All HPV samples will be processed in a certified central laboratory. Other sexually transmitted infections will be evaluated by interview and by rapid testing for HIV and syphilis. Strict quality control will be conducted using different procedures, including the training and certification of the health professionals responsible for acquiring data and monitoring visits. ETHICS AND DISSEMINATION: The project was approved by the research ethics committee of the main institution and the corresponding ethics committees of the recruitment sites. Due to the literature gap on the sexual health of sex workers and MSM and the intense stigma surrounding these populations, a critical analysis of the study results will contribute to epidemiological knowledge and will be useful for the development of strategies against virus morbidities.

Factors associated with HPV and other self-reported STI coinfections among sexually active Brazilian young adults: cross-sectional nationwide study.

OBJECTIVES: To analyse factors associated with genital human papillomavirus (HPV) and other self-reported sexually transmitted infection (STI) coinfections among women and men aged 16-25 years from Brazil. DESIGN: A cross-sectional, nationwide, multicentre study. SETTING: 119 primary healthcare centres between September 2016 and November 2017. PARTICIPANTS: 6388 sexually active young adults were enrolled by trained health professionals. PRIMARY OUTCOME MEASURE: Genital HPV and other self-reported STI coinfections. RESULTS: Of 3512 participants with valid data for genital HPV and (STI)-positive status, 276 (9.60%, 95% CI 7.82% to 11.36%) had HPV/STI coinfection. Among men, HPV/STI coinfection was more prevalent than HPV infection alone. Among HPV-positive participants, the percentage of subjects who reported having another STI was highest for gonorrhoea at 4.24% (95% CI 2.67% to 5.81%), followed by syphilis, herpes and HIV. Smoking, drug use and ever having a same-sex sexual experience were risk factors that were uniquely associated with HPV/STI coinfection compared with HPV infection alone. CONCLUSIONS: The results identified a low prevalence of self-reported STIs, but in participants with at least one STI, the prevalence of HPV was high. These results reinforce the importance of implementing strategies to prevent risky behaviours among Brazilian young adults.

Adequacy of prenatal care, diagnosis and treatment of syphilis in pregnancy: a study with open data from Brazilian state capitals.

To assess the adequacy of prenatal care offered in the Brazilian capital cities and the diagnosis of gestational syphilis through public data from health information systems. The modified Kotelchuck index for adequacy of prenatal care was built using Brazilian Information System on Live Births (SINASC) data. Data on gestational syphilis, congenital syphilis, estimated population coverage by the Family Health Strategy (FHS), the Municipal Human Development Index (MHDI) and data from National Program for Access and Quality Improvement in Primary Care (PMAQ-AB) were accessed in public sites. The profile of pregnant women associated with inadequate care was assessed by logistic regression. In total, 685,286 births were analyzed. Only 2.3% of women did not attend prenatal appointments. The mean adequacy was 79.7%. No correlation was found between adequacy of prenatal care and FHS coverage (p = 0.172), but a positive correlation was found with the MHDI (p < 0.001). Inadequacy of prenatal care was associated with age below 20 years old, schooling less than 4 years, non-white skin color and not having a partner. Among the congenital syphilis cases, 17.2% of mothers did not attend prenatal care. Gestational syphilis more often affected vulnerable women, including a higher proportion of adolescents, women with low schooling, and women of non-white color. The PMAQ-AB showed a median availability of 27.3% for syphilis rapid tests, 67.7% for benzathine penicillin, and 86.7% for benzathine penicillin administration by health teams. The use of public data showed a low adequacy of prenatal care in Brazilian capitals, denoting insufficient quality for the diagnosis and treatment of gestational syphilis, despite the availability of supplies. Continuous monitoring can be carried out using public data, indicating to local strategies to eliminate congenital syphilis.

Tuberculosis burden on AIDS in Brazil: A study using linked databases.

OBJECTIVES: To estimate the burden of tuberculosis (TB) in reported AIDS cases, to compare the characteristics of TB/HIV subjects with those without TB and to evaluate survival with or without TB in Brazil. METHODS: The data source was the linked database between AIDS (2011-2014) and TB (2011-2014) databases from the Notifiable Diseases Information System (SINAN). The sociodemographic, clinical, laboratory results and use of antiretroviral therapy (ART) data were compared by TB occurrence or not. Survival probability was estimated using the Kaplan-Meier method and associated factors were sought using Cox regression. RESULTS: The proportion of TB diagnosed from 2011 to 2014 among AIDS cases reported between 2006 and 2014 was 6.3%. Subjects coinfected with TB were predominantly male, older, with lower schooling, with lower CD4 count, higher viral load, and higher proportion of ART initiation than those without TB. 57.5% were diagnosed with HIV before TB, 38.2% as concurrent TB/HIV and 4.3% with TB before HIV. 16,466 reported TB cases were not found in the AIDS database, although registered as HIV-infected in the SINAN TB database between 2011 and 2014. Median survival for PLHIV was 581 days, with 582 for those without TB, significantly higher than 547 for those with TB (log-rank teste, p = 0,001). In the Cox multivariate analysis, male gender [aHR = 1.27 (CI 95% 1.22-1.33)], older age [aHR = 1.020 (CI 95% 1.019-1.022)] and TB coinfection [aHR = 1.97 (CI 95% 1.88-2.07)] were positively associated with adjusted hazard of death, whereas CD4 count 200-499 cells [aHR = 0.21 (CI 95% 0.20-0.22)] and receiving ART [aHR = 0.2 2(CI 95% 0.21-0.23)] reduced the risk of death. CONCLUSIONS: HIV-infected subjects should be screened for TB at care entry, to minimize diagnosis and treatment delays when active TB is present or to increase the odds of being offered latent TB infection therapy to prevent TB. On the other hand, TB cases should be promptly tested for HIV. All those will contribute to reduce mortality among people living with AIDS.

Sexual behavior across the transition to adulthood and sexually transmitted infections: Findings from the national survey of human papillomavirus prevalence (POP-Brazil).

The sexual behaviors of 15- to 24-year-olds increase the risk of this population to acquire sexually transmitted infections (STIs). The present study aimed to describe the sexual behavior in the transition to adulthood Brazilian population and its association with STI history.We analyzed cross-sectional data collected from 8562 sexually active women and men who participated in the National Survey of Human Papillomavirus Prevalence (POP-Brazil). This large-scale survey enrolled participants from 26 Brazilian capitals and the Federal District. Professionals from primary care facilities were trained to collect data utilizing a standardized questionnaire with questions on sociodemographic, sexual behavior, and drug use. We constructed a Poisson model with robust variance for both crude and adjusted analysis to investigate the associations between the variables. To adjust the distribution of the sample to the study population, we weighted the measures by the population size in each city and by gender.There were differences in several aspects from sexual behavior between genders. The majority of men reported an early sexual initiation, more sexual partners, and a different practice in sexual positions when compared with women. Women reported use of contraception more frequently than men (P < .001). The use of alcohol and drugs and the use of drugs before sexual intercourse impact in STIs equally between the genders. Exclusive for women, the presence of any STI was associated with the practice of vaginal sex and other types of intercourse (adjusted prevalence ratio [APR] 1.43, 95% CI 1.08-1.88). For men, the number of sexual partners in the last year (APR 1.02, 95% CI 1.01-1.04), not having vaginal sex (APR 3.25, 95% CI 1.78-5.92) and sexual experience with someone of the same sex (APR 4.05, 95% CI, 2.88-5.70) were associated with a higher presence of STIs.This is the first report regarding sexual behavior in a nationally representative population sample in Brazil. This study provides more valid estimates of sexual behavior and associated STIs, identifying important differences in sexual behavior and identifying predictors for referred STIs among females and males.

POP-Brazil study protocol: a nationwide cross-sectional evaluation of the prevalence and genotype distribution of human papillomavirus (HPV) in Brazil.

INTRODUCTION: Human papillomavirus (HPV) is associated with the development of genital warts and different types of cancer, including virtually all cervical cancers and a considerable number of penile, anal and oropharyngeal cancers. Data regarding the prevalence of HPV infection in Brazil are limited and fragmented. We aim to determine HPV prevalence in sexually active women and men aged 16-25 years and to investigate regional differences in virus prevalence and types. METHODS AND ANALYSIS: This is a nationwide, multicentric, cross-sectional, prospective study that will include participants aged 16-25 years from all Brazilian capital cities. Recruitment will occur in primary health units by trained health professionals who will be responsible for collecting biological samples and interviewing the volunteers. After signing informed consent, all participants will answer a questionnaire that will collect sociodemographic and behavioural data. All samples will be processed in a certified central laboratory, and strict quality control will be performed by many different procedures, including double data entry, training and certification of primary care health professionals responsible for data collection, simulation of interviews, and auditing and monitoring of visits. The sample size will be standardised based on the population distribution of each capital using SAS and R statistical software. ETHICS AND DISSEMINATION: The project was approved by the research ethics committee of the main institution and the corresponding ethics committees of the recruitment sites. This will be the first Brazilian nationwide study to determine overall HPV prevalence and to examine regional differences and social, demographic and behavioural factors related to HPV infection. Critical analysis of the study results will contribute to epidemiological knowledge and will set a baseline for future evaluation of the impact of the National HPV Vaccination Program.