ARTICLE
Knowledge of Human Papillomavirus, cervical cancer, and anti-HPV vaccine among students from a university in Goiás, Brazil

INTRODUCTION

Human papillomavirus (HPV) is the most common sexually transmitted infection⁽¹⁾. Therefore, HPV infection is the most studied as it is the main specifc cause of 99.7% of cases of cervical cancer worldwide⁽²⁾.

There are several risk factors for cervical cancer. The main risk factor is the HPV infection, followed by age and early onset of sexual activity among women under 25 years of age. High number of sexual partners, continuous use of oral contraceptives, immunosuppression (caused by infection with the human immunodefciency virus – HIV – or use of immunosuppressants), and smoking may be related to HPV infection⁽³⁾.

There are nearly 200 sequenced HPV genotypes. Of these, approximately 40 types can infect the genital mucosa and evolve to cancer. Genetically identifed types are classifed as high risk and low risk, according to their oncogenic potential⁽⁴⁾. Twelve HPV types, namely, HPV-16, HPV-18, HPV-31, HPV-33, HPV-35, HPV-39, HPV-45, HPV-51, HPV-52, HPV-56, HPV-58, and HPV-59 are known as high-risk types, and 11 HPV types, namely, HPV-6, HPV-11, HPV-40, HPV-42, HPV-43, HPV-44, HPV-54, HPV-61, HPV-72, HPV-81, and HPV-CP6108 are know as low-risk types. Another group considered as intermediate-risk type is composed of 8 HPV types categorized as probable high-risk (HPV-26, HPV-53, HPV-66, HPV-67, HPV-68, HPV-70, HPV-73 and HPV-82)^(5,6).

According to the World Health Organization (WHO), cervical cancer is the fourth most common cancer worldwide, excluding nonmelanoma skin cancer, with approximately 530,000 new cases per year. Cervical cancer is the main cause of death of 265,000 women per year⁽⁷⁾. In Brazil, cervical cancer is the third most common among the Brazilian population, excluding nonmelanoma skin cancer. The estimate for 2016 is 16,340 new cases with a risk of 15.85 cases per 100,000 women⁽⁸⁾.

The Pap smear is the most common gynecological exam for cancer prevention. It enables the early detection of precursor lesions in asymptomatic women and may prevent the disease progression with appropriate monitoring and treatment⁽⁹⁾. The gynecological examination is quick, sensitive, and does not cause discomfort to the patient, which characterizes it as a safe screening method. The Pap smear is recommended by the WHO as the main prevention method to be included in programs to combat cervical cancer in several countries. According to the WHO, with a target population coverage of at least 80% and proper diagnosis and treatment of abnormal cases, the incidence of invasive cervical cancer may decline by 60 to 90% in average⁽¹⁰⁾.

Two prophylactic HPV vaccines have been approved with the aim of strengthening cervical cancer prevention: Gardasil^® (Merck Sharp & Dohme, Whitehouse Station, New Jersey, United States of America) and Cervarix^® (Glaxo Smith & Kline Biologicals, Rixensart, Belgium). These two vaccines were approved by the Food and Drug Administration (FDA) in June 2006 and October 2009, respectively⁽¹¹⁾.

In 2014, the FDA approved a 9-valent HPV vaccine. Gardasil 9^® vaccine prevents cervical, vulvar, vaginal, and anal cancers caused by HPV types 16, 18, 31, 33, 45, 52, and 58; and genital warts caused by HPV types 6 or 11. In addition, it provides protection against cervical cancer with up to 90% effcacy. Until the publication of this paper, the tetravalent vaccine had not yet been replaced by the 9-valent vaccine in all health programs worldwide. Only in some developed countries the vaccine was implemented, but not in the health services^(12,13,14).

In clinical studies, Gardasil^® vaccine shown to be highly effective against cancer in the anal and genital area, showing 100% eff-cacy against precancerous lesions and vaginal/vulvar cancers, 95% effcacy against cervical intraepithelial neoplasm, and 99% eff-cacy against genital lesions caused by HPV types 6, 11, 16, and 18. The duration of immunity of this vaccine is at least fve years^(15,16).

OBJECTIVE

To evaluate the perception and knowledge of the main aspects related to HPV infection, its implications in the development of cervical cancer, and the HPV vaccine among undergraduate biomedicine students at the Pontifícia Universidade Católica de Goiás (PUC Goiás).

METHODS

This was a descriptive study carried out in the undergraduate biomedicine program at PUC Goiás. This study included the administration of a questionnaire which was elaborated based on a literature review of similar studies carried out in other countries^{(17,18,19,20)} and on studies that have been developed in medical and nursing programs at the referred university. In these studies, content included HPV infection, cervical cancer, and the HPV vaccine.

The total number of students enrolled in the undergraduate biomedicine program at PUC Goiás was 378 in 2015. Initially, 268 students were studied, with a participation rate of 70.9%. The sample was considered representative; however, only 266 students were included in the study because two participants did not respond to most questions.

After reading and signing the informed consent form (ICF), the subjects who agreed to be part of the research received the questionnaire.

Sample group was defned according to the following inclusion criteria: to be properly enrolled in the undergraduate program in Biological Sciences (medical/biomedicine modality) of the institution, age over 18 years, be present when questionnaires were administered, agreed to participate in this research after explanation of the study objectives, and have signed the consent form.

The research project was approved by the Research Ethics Committee of PUC Goiás under the opinion number 1,227,310. Data were collected by means of a questionnaire containing 38 multiple choice questions, which were distributed as follows: 5 aimed at sample characterization, 12 assessed knowledge of HPV, 15 tested knowledge of cervical cancer, and the remaining 6 were about the anti-HPV vaccine. The topics covered in the survey included defnitions, routes of transmission and prevention of the virus infection, cancer development risks, administration and use of the vaccine, among others.

The questionnaires were administered at the beginning or end of regular classes of the course. Students had enough time to answer the questions.

Participants’ knowledge was evaluated based on the percentage of correct answers for each question on the three themes: knowledge of HPV, cervical cancer, and anti-HPV vaccine.

Score averages obtained for each group of questions were classifed into “satisfactory,” when scores were greater than 80%; “reasonable,” when they were between 70 and 80%; and “insuffcient,” when they were below 70%.

Information was collected and organized in a database, whose data were inputted in Microsoft Offce Excel^® 2013 spreadsheets (Microsoft Corporation, Redmond, Washington, United States of America). For statistical analysis, data were transferred to the program R Core Team 2012 and were analyzed by descriptive and comparative statistical methods using the chi-square test (χ²), with 95% confdence interval and signifcant value below 0.05. Results were shown in graphs and tables using the program R Commander (Rcmdr), 2005.

RESULTS

Biomedicine student’s characteristics that were evaluated in this study are shown in Table 1. The questionnaires that were administered to the 266 undergraduate biomedicine students were analyzed. Among the students, 81.6% (n = 217) were female and 18.4% (n=49) were male. The ages of the participants ranged from 18 to 42, and the majority (n=237; 89.1%) were aged 18–23 years. Among the participants, 242 (91.0%) were single or divorced, and 166 (62.4%) reported having an active sex life.

Table 1:

Sample characterization of biomedicine students at the Pontifícia Universidade Católica de Goiás (PUC Goiás), in 2015.

Source: School of Medical, Pharmaceutical, and Biomedical Sciences.

NI: not informed.

With regard to the participants’ knowledge of HPV infection, the overall mean score was 75.7%. The highest scores were obtained on questions pertaining to knowledge of HPV existence (99.6%) and awareness of HPV as a sexually transmitted disease (96.2%). However, when the knowledge of HPV transmission through kissing was evaluated, the percentage of correct answers was 23.3%. This was the lowest score of participants’ knowledge of HPV.

A statistically signifcant difference was observed (p=0.026) on the question that investigated the knowledge of a possible transmission of HPV from mother to child. Male participants answered correctly 81.6% of questions, whereas female participants answered correctly 67.7% of questions (Table 2).

Table 2:

University students’ knowledge of the Human Papillomavirus (HPV) Infection, Pontifícia Universidade Católica de Goiás (PUC Goiás), 2015.

Source: School of Medical, Pharmaceutical, and Biomedical Sciences.

NI: not informed; HPV: Human Papillomavirus.

The overall mean score on participants’ knowledge of cervical cancer was 68.9%. The highest scores were obtained on the question that assessed knowledge of HPV infection as main agent of cervical cancer (98.1%) and awareness of sex with multiple partners as a risk factor for such cancer (92.1%). Statistically signifcant differences were found on the questions on the association of some foods with cervical cancer (p=0.037) and early onset of sexual intercourse as a risk factor for the same type of cancer (p=0.008); in these two questions female participants stood out in relation to male participants, with scores equivalent to 81.6 % and 74.2%, respectively (Table 3).

Table 3:

University students’ knowledge of the cervical cancer, Pontifícia Universidade Católica de Goiás (PUC Goiás), 2015.

Source: School of Medical, Pharmaceutical, and Biomedical Sciences.

NI: not informed; HPV: Human Papillomavirus; IUD: intrauterine device.

With regard to the assessment of participants’ knowledge of the anti-HPV vaccine, mean score was 69.3%. Male participants achieve a slightly higher score (71.8%) compared to the mean score of female participants (69.5%) (Table 4).

Table 4:

University students’ knowledge of anti-HPV vaccine, Pontifícia Universidade Católica de Goiás (PUC Goiás), 2015.

Source: School of Medical, Pharmaceutical, and Biomedical Sciences.

NI: not informed; HPV: Human Papillomavirus.

The highest rate of correct answers was related to the question on knowledge of the existence of anti-HPV vaccine (97.4%), and the lowest score was on the vaccination recommended age range (14.3%). This question showed a statistically signifcant difference (p=0.000393). Another statistically signifcant difference was identifed on the question on the recommended sex for anti-HPV vaccine (p=0.005), with male participants obtaining higher scores, equivalent to 65.3% (Table 4).

In the assessment of overall performance concerning HPV infection – including cervical cancer and anti-HPV vaccine – the highest level of knowledge demonstrated by the highest scores was related to HPV (75.7%), and the lowest scores were related to cervical cancer (68.9%) (Table 5).

Table 5:

Average of correct responses according to variables of the biomedicine students from the Pontifícia Universidade Católica de Goiás (PUC Goiás), 2015.

Source: School of Medical, Pharmaceutical, and Biomedical Sciences.

NI: not informed; HPV: Human Papillomavirus.

DISCUSSION

In this study, the majority of participants were single/divorced (91.0%) and had active sexual life (62.4%). Most of them were aged 18 to 23 years (89.1%). These data show that the participants have a high degree of exposure to the main risk factors for HPV infection and cervical cancer⁽³⁾.

When questioned about the HPV infection, most participants were aware of the virus and identifed the infection as a sexually transmitted disease. This is an important fnding which indicates the students’ concern about avoiding exposure to risk factors in the sexual intercourse. An overall mean score equivalent to 75.7% showed that the participants have reasonable level of knowledge of the pathogenesis of HPV. However, when assessing the HPV transmission through kissing, only 23.3% of participants responded correctly. This is worrying, as similar oral and genital lesions caused by the HPV have been discovered, which suggested their inclusion in the development of oral cancer. In such cases, association of open-mouth (“French”) kissing with oral HPV infection and also the transmission of genital HPV positive to the oral tract through oral sex were revealed^(21,22).

A statistically signifcant difference in relation to female participants (74.2%) compared to male participants (55.1%) was observed (p=0.008). This allowed us to infer that women in this study have concerns about the HPV transmission and probably adhere to other preventive measures, as women under 25 years of age are a risk group with less chance of developing cervical cancer⁽³⁾.

The male population is primarily responsible for the transmission of HPV to women, because they act as reservoirs, transmitting oncogenic types more easily to women than the opposite – from women to men⁽²³⁾. Most of these infections are asymptomatic and transient, and usually undetectable within one or two years; however, persistent infection favors the development of future neoplasms⁽²⁴⁾.

When the students were asked about the existence of vertical transmission of HPV, 70.3% of them were aware of this type of transmission, with signifcant frequency (p=0.026) and greater knowledge score among male participants (81.6%); women presented 67.7% of correct responses. However, 27.4% of students did not consider this possibility. In fact, during the passage of the fetus through the birth canal, the HPV infected mucosa of the mother can infect and stimulate the proliferation of the virus in the upper airways, which can evolve to recurrent respiratory papillomatosis with lung involvement^(25,26).

With regard to the assessment of the HPV cure, an unsatisfactory level of knowledge was observed (65.4%). This is an important fact that suggests strengthening the knowledge of this peculiarity of HPV infection is necessary, as the natural history of the problem is the spontaneous healing. However, the presence of oncogenic types associated with multiple risk factors can lead to persistent infection, which in turn can lead to neoplastic lesions and evolve to cervical cancer^(24,27). Nevertheless, when cervical cancer is early detected, it is possible to delay the development of invasive cancer or even cure it by means of clinical interventions such as colposcopy and biopsy, local excision, conization, and hysterectomy⁽²⁸⁾.

Participants’ knowledge of cervical cancer was considered unsatisfactory and corresponded to the worst score found in the study. However, most of the students in this study were aware of the main risk factors for cervical cancer, such as genetic predisposition, bacterial infection, early onset of sexual intercourse, and multiple sexual partners.

A signifcant number of students were unaware of smoking as a risk factor for the development of cervical cancer (49.2%). Tobacco is capable of exposing the DNA in cervical epithelial cells to nicotine, cotinine, and its metabolites, and of promoting mutagenesis, genomic damage, and proliferation of these cells. In addition, it can induce immunosuppression, facilitating the occurrence of lesions and HPV persistence. Brazilian studies have shown greater probability of cancer in women who smoke; it was estimated that smoking at least 100 cigarettes during their lifetime would be a potential risk factor for the development of cervical cancer^(29,30).

In general context, students know the signs and symptoms of cervical cancer. This type of cancer grows slowly and it is usually asymptomatic in the early stage; however, the evolution of the disease may lead to intermittent vaginal bleeding, pain after intercourse, abnormal vaginal discharge, and abdominal pain⁽³¹⁾.

Cervical cancer is a preventable and curable disease; however, early detection of precursor lesions by means of the Pap test, which is the main strategy to control this cancer, is necessary. Primary prevention, which is obtained through HPV vaccines that provide protection for the main HPV types is also essential^(6,11,16,18).

Regarding the anti-HPV vaccine as a new prevention method for HPV infection and cervical cancer, students’ knowledge score showed a low average. In this study, most participants heard about the vaccine (97.4%) and know that it is already included in the National Immunization Program (82.3%), which may be explained by the media coverage of the vaccination campaign promoted by the Ministry of Health in 2014⁽³¹⁾. Results of a research carried out in hospitals located in Bangkok, Thailand⁽²⁰⁾, revealed that nurses (63%) and physicians (73%) respondents believed that the vaccine is introduced for both boys and girls before the onset of sexual activity.

The period that the participant was attending had no signifcant infuence on the knowledge of the cervical cancer and anti-HPV vaccine; however, in this study, increased knowledge of HPV infection was found among participants who were enrolled at “Immunology” and “Virology” (4th period), and mainly at “Cytopathology” (6th period), which had a strong impact. However, the level of knowledge of the subject was relatively stable until the last period of the biomedicine program.

The biomedical scientist contributes to the promotion of health of the population, especially in the prevention of diseases, since he or she is a professional who can work in several areas⁽³²⁾. This study results suggested that there is lack of adequate knowledge of the key themes peculiarities. A greater coverage of the subject is relevant for these students, so they may promote adequate health care to the population, as future biomedical scientists.

CONCLUSION

In view of the results obtained in this study, the overall performance of students was considered reasonable, suggesting that the knowledge acquired by students during the biomedicine program was not sufficient. These data corroborate other studies carried out in different locations and health fields^{(17,18,19,20)} which have addressed similarly HPV infection, cervical cancer, and anti-HPV vaccine.

The need for a broader coverage of this particular theme in the classroom should be highlighted, in addition to the development of new continuing education strategies, such as courses, symposiums, and workshops, conducted by people responsible to inform the students about HPV, its complications and prevention, as well as the encouragement of academic leagues and advertising campaigns.