Revista Adolescência e Saúde

Revista Oficial do Núcleo de Estudos da Saúde do Adolescente / UERJ

NESA Publicação oficial
ISSN: 2177-5281 (Online)

Vol. 14 nº 3 - Jul/Sep - 2017

Original Article Imprimir 

Páginas 38 a 45

Immunization against HPV: level of adolescents' knowledge

Inmunización contra HPV: nivel de conocimiento de los adolescentes

Imunização contra HPV: nível de conhecimento dos adolescentes

Autores: Maria Regina Orofino Kreuger1; Luiza Soster Lizott2; Henrique de Almeida Friedrich3

1. Post-Doctoral Pupil, Ghent University, (UGENT). Ghent, Belgium. PhD in Experimental and Comparative Pathology , São Paulo University (USP). São Paulo, São Paulo State,Brazil. Tenured Lecturer, Health Sciences Center, Vale do Itajaí University (UNIVALI). Itajaí, Santa Catarina State, Brazil
2. Graduand in Medicine, Health Sciences Center, Vale do Itajaí University (UNIVALI). Itajaí, Santa Catarina State, Brazil
3. Graduand in Medicine, pelo Health Sciences Center, Vale do Itajaí University (UNIVALI). Itajaí, Santa Catarina State, Brazil

Maria Regina Orofino Kreuger
Universidade do Vale do Itajaí, Centro Ciências da Saúde
Rua Uruguai, 458, Centro
Itajaí, SC, Brasil. CEP: 88302-202

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How to cite this article

Keywords: Papillomaviridae, vaccination, communicable disease control.
Descritores: Papillomaviridae, vacinação, controle de doenças transmissíveis.

OBJECTIVE: Evaluate the adolescent's knowledge about vaccines against HPV and determine the number of youngsters vaccinated against it.
METHODS: Cross-sectional unicentric study with 390 students (ages between 12 and 17 years old) in Itajaí-SC. Data collection made through an objective questionnaire. In addition to the descriptive analysis, the chi-square test (X2) was used and the level of significance was set at p <0.05.
RESULTS: Among the 390 participants, 188 were female (average age 14.41 years). 86,92% have reported to know about the vaccine, emphasizing that the frequency of male individuals who said they have never heard about the vaccine was higher than the female (p <0.05).
CONCLUSION: Most of the youngsters have heard about the vaccine, but less than half knows that both sexes can be vaccinated. Nearly half of female participants reported having had the vaccine, while only 5% of male participants reported the same. Male gender presented a level of knowledge below the female. In addition, the information from the physicians was mostly cited by female participants.

OBJETIVO: Evaluar el nivel de conocimiento de los adolescentes sobre las vacunas contra el HPV y determinar el número de jóvenes vacunados.
MÉTODOS: Estudio transversal unicéntrico, hecho con 390 escolares (edades entre 12 y 17 años) de Itajaí-SC. Relección de datos hecha a través de cuestionario objetivo. Además del análisis descriptivo, el test Chi-Cuadrado (X²) fue utilizado y el nivel de significancia fue de p<0,05.
RESULTADOS: De los 390 participantes, 188 eran del sexo femenino (edad Promedio de 14,41 años). Un 86,9% indicó ya haber oído hablar sobre la vacuna, siendo la frecuencia de individuos masculinos que no conocían la vacuna superior al género femenino (p<0,05).
CONCLUSIÓN: La mayoría de los jóvenes ya escuchó hablar sobre la vacuna, sin embargo, menos de la mitad sabe que ambos sexos pueden ser vacunados. Aproximadamente la mitad de las niñas indicó haber realizado la vacuna, mientras solamente el 5% de los niños relataron lo mismo. El sexo masculino presentó un nivel de conocimiento inferior al femenino. Además, la información a través de médicos fue citada principalmente por las niñas.

OBJETIVO: Avaliar o nível de conhecimento dos adolescentes sobre as vacinas contra o HPV e determinar o número de jovens vacinados.
MÉTODOS: Estudo transversal unicêntrico, feito com 390 escolares (idades entre 12 e 17 anos) de Itajaí-SC. Coleta de dados feita através de questionário objetivo. Além da análise descritiva, o teste qui-quadrado (X2) foi utilizado e o nível de significância foi de p<0,05.
RESULTADOS: Dos 390 participantes, 188 eram do sexo feminino (idade média de 14,41 anos). 86,9% referiram já ter ouvido falar sobre a vacina, sendo a frequência de indivíduos masculinos que não conheciam a vacina foi superior que a feminina (p<0,05).
CONCLUSÃO: A maioria dos jovens já ouviu falar sobre a vacina, contudo menos da metade sabe que ambos os sexos podem ser vacinados. Aproximadamente metade das meninas referiu ter realizado a vacina, enquanto somente 5% dos meninos relataram o mesmo. O sexo masculino apresentou um nível de conhecimento inferior ao feminino. Além disso, a informação através de médicos foi citada principalmente pelas meninas.


Worldwide, HPV infection is rated as the main risk factor for cervical cancer, which is the second most common among women, particularly in developing countries such as Brazil1. In a single year, HPV accounts for around 500,000 new cases of cervical neoplasia2 around the world.

Due to high HPV rates, prophylactic vaccines appeared as an efficacious way of preventing viral infections, preferably before becoming sexually active, in order to avoid contacts with the virus prior to vaccination3. It is stressed that for children between 9 and 13 years old, parents are still in the habit of making sure that they receive other vaccines, particularly as this is the stage of life when vaccination provides antibody levels that are far
higher than the natural immunity resulting from HPV infection4.

The bivalent form of this vaccine acts against the 16 and 18 serotypes, while the quadrivalent acts against these and the 6 and 11 subspecies5. These serotypes account for 90% of warts, 70% of carcinomas and high-grade pre-cancerous lesions, and 35% to 50% of low-grade anal-genital lesions6.

The vaccine currently used by Brazil´s Ministry of Health for HPV is human papillomavirus 6, 11, 16 and 18 (recombinant), with the quadrivalent form offering protection against HPV with low oncogenic risk (HPV 6 and 11) and also high risk (HPV 16 and 18)4.

Thus, aware that prophylactic HPV vaccines constitute a major protection factor against the development of cervical cancer and diseases associated with HPV, with adolescence being the time of greatest risk for viral infections3, the objective of this study was to assess the level of knowledge about HPV vaccines among adolescents.


To assess the level of knowledge about HPV vaccines among adolescents and define the number of vaccinated youngsters.


In order to conduct this study, approval was obtained from the Ethics and Research Committee at the Vale do Itajaí University (UNIVALI). The data were kept completely confidential, used in compliance with the rules laid down by Resolution CNS Nº 466/12 issued by the National Health Council (CNS).

This was a cross-sectional study lasting a full year (2015), with the sample consisting of pupils properly regularly enrolled at the UNIVALI Laboratory School (CAU) from 6th grade of primary school through to the final year of high school, with ages between 11 and 18 years old. Data were collected after Deeds of Informed Consent had been signed by parents or guardians, in addition to Deeds of Assent signed by the young respondents.

The data were collected through completing a questionnaire approved in advance by the CAU Coordination Office through signature of the Deed of Assent. This Office assigned some ten minutes of time for each class between March through to June 2015, with the teachers remaining in the room as the data were collected. The questionnaire consisted of objective questions such as: "Have you ever heard about the HPV vaccine?", "Who can be vaccinated (men, women or both)?", and "Are you vaccinated?", completed individually. The results were then computed, excluding those who were not there on the data collection day, as well as those not signing a deed of assent or without parental permission to participate. In addition to the descriptive analysis, the chi-square test (X²) was used to establish the homogeneity of the proportions with a significance level of p<0.05.


The findings of this study were drawn from the questionnaires completed by primary and high school pupils at the CAU Laboratory School, consisting of 390 youngsters between 11 and 18 years of age, of whom 188 were girls (48.2%) and 202 were boys (51.7%). The mean age of these adolescents was 14.41 years old, at 14.39 years of age for girls and 14.44 for boys.

The purpose of the questionnaire was to assess knowledge about HPV vaccine among these adolescents, with 86.9% of them stating that they had already heard about the vaccine at some point, with 94.1% of the total being girls and 80.2% boys.

This survey population was asked about where or from whom they heard about the HPV vaccine, with the data presented in Table 1. The source of information mentioned most frequently by these youngsters was school (34.8%), followed by television (22.3%). It is also stressed that 13% of them stated that they had never heard about the HPV vaccine, of whom 40 were boys and 11 were girls. In a gender comparison, the number of boys who had never heard about or did not recall the vaccine is statistically superior to the number of girls at p<0.05. Furthermore, the number of girls who stated that they had received information from physicians and parents is also statistically higher than the number of boys.

Table 2 offers an analysis of knowledge among pupils of who can be vaccinated against HPV, with 57.4% stating that only girls can be vaccinated against HPV, while 39.2% said that both boys and girls could take the vaccine.

The number of youngsters already vaccinated against HPV with at least one dose is shown in Table 3. Out of the total number of adolescents, 25.3% stated that they had been vaccinated with at least one dose, of whom 10 were boys and the remaining 89 were girls. Nevertheless, 21.7% of these adolescents stated that they did not know whether or not they had been vaccinated. The difference between the number of boys and girls who had been vaccinated was statistically significant at p<0.05.

The remaining items in the questionnaire were directed only to youngsters who had already had at least one dose of vaccine, consequently totaling 99 adolescents. Table 4 presents data on the number of doses that these youngsters had received so far: among these 99 pupils, 43.4% said that they had taken only the first dose; 43.4% had taken both doses; and 10.10% said they had already taken all three doses. The mean age of the pupils was 12.2 years old for the first dose, with the lowest and the highest ages found being 10 and 17 years old respectively. Among the girls, the mean age was 12.2 years, and 12.6 for the boys.

Table 5 shows that the main sources of incentives prompting these youngsters to be vaccinated were their parents, mentioned by 45.4% of the 99 vaccinated youngsters, followed by school (40.4%), and healthcare practitioners in third place (10.1%).


Education programs targeting adolescents are important for preventing specific problems during this life stage, including infection by HPV and other sexually transmitted diseases (STD), which require specialized knowledge7 for successful implementation. Consequently, this study encompassed 390 adolescents (188 girls and 202 boys) between 11 and 18 years of age.

Other studies exploring knowledge on HPV and its vaccines, such as that conducted in Piauí State with 218 respondents, the age bracket addressed was between 17 and 34 years of age, with 78% women8. The study conducted in Ribeirão Preto addressed a population of women between 17 and 19 years old9, while a study at a private university in Pernambuco State encompassed respondents between 21 and 25 years of age, of whom 65.7% were female10. Contrasting with these studies, this paper focused on a younger age bracket because young adolescents today are rated as top priority for HPV vaccination. It is also during this stage of life that sexual exploration begins, coming into contact for the first time with STDs, meaning that it is vital to focus on this age group.

With regard to knowledge about the HPV vaccine among these youngsters, 86.9% stated that they had heard about the vaccine, while in other studies, only 36% and 36.5% of students knew about the vaccine8, 10. More alarmingly, in a study of 538 users of Brazil's Unified National Health System (SUS), less than 9% of the respondents stated that they had heard about HPV vaccines11. This indicates a massive divergence between the results of this study and other projects, which may be due to the fact that the other studies were conducted with university students and adults who may well have not acquired much knowledge on this subject during their schooldays8. The absence of awareness-heightening campaigns about the consequences of HPV infections and vaccines targeting these age brackets may also be the reason for the lack of knowledge in these groups.

It was noted that schools and media were actively disseminating information about HPV vaccines, as 34.8% and 22.3% of the students respectively mentioned them as their main sources of information. The above-mentioned study of SUS users found the media to be the source of information mentioned most frequently by the respondents, with this study not encompassing schoolchildren11. It is thus clear that the media and particularly the school for adolescents, are of crucial importance for sex education, encouraging preventive attitudes among young people.

Still regarding sources of information on HPV vaccine mentioned by these youngsters, when the replies were compared by gender, it was clear that more boys stated that they had never heard about the HPV vaccine. Moreover, the girls mentioned physicians and parents as their main sources of information more frequency than the boys. This may have been due to the fact that only 8.5% of the boys see an urologist each year while 41.1% of the women mentioned annual visits to a gynecologist10. Another justification for this might be the fact that the mothers of teenage girls are more aware of cervical cancer and would thus encourage them to see a gynecologist7 at younger ages.

When asked about who could take the HPV vaccine (only girls, boys or both), 57.4% stated that only girls could be vaccinated, while 39.2% stated that both boys and girls could be vaccinated. The high error level for the belief that only girls could be vaccinated was probably due to the rapid spread of information on the consequences of HPV among women, including cervical cancer. Furthermore, the fact that the SUS made the vaccine available initially only to adolescent girls4 may have contributed to this misunderstanding. Probably for the same reasons, this study showed that girls are significantly more vaccinated than boys, with less than 5% of adolescent males vaccinated. Nevertheless, male vaccination is justified by the benefit of protection against the consequences of infection, while speeding up protection processes for women11. It is thus vital that adolescent boys are aware of the virus and ways of avoiding it.

Among the 188 female respondents, 47.3% stated that they had taken at least the first dose of the vaccine. The Brazilian Ministry of Health set a goal of vaccinating 80% of the target public (4.94 million youngsters) for 2015, which represents around 3.95 million girls between 9 and 11 years of age4.

Among the 25.3% (99 youngsters) who said that they had been vaccinated, 43.4% stated that they had taken only the first dose, 43.4% said that they had taken two doses, with 10.1% confirming that they had taken all three doses. It is vital that these adolescents are aware of the importance of completing all three doses of the HPV vaccine. Healthcare practitioners involved in vaccination proceedings must advise these youngsters properly on taking each dose, with the respective schedules. The original vaccine schedule established by Brazil´s Ministry of Health consisted of three doses administered at 0, 6 and 60 months4, by 2017, when it then introduced a two-dose vaccine scheme (0 and 6 months), maintaining the three-dose scheme (0, 2 and 6 months) for immune-compromised youngsters of both genders between 9 and 26 years of age.

The 89 vaccinated girls posted a mean age of 12.2 years of age for the first dose of the vaccine, with 10 and 17 years old being the minimum and maximum ages found, respectively. According to the Brazilian Ministry of Health, the priority target population for 2015 consisted of girls between 9 and 11 years old4, expanding to encompass girls between 9 and 14 years old in 2017, as well as boys, initially between 12 and 13 years old, with a two-dose vaccine scheme (0 and 6 months).

Among the 99 vaccinated youngsters, 45.4% stated that their parents were the main source of encouragement for vaccination, with 40.4% mentioning school. Once again, it is thus quite clear that school is one of the main sources for disseminating information and incentives, stressing that enlightened parents and guardians play a significantly influential role in teen vaccination. In counterpart, it may be noted that a lack of knowledge and enlightenment among the parents and guardians of these youngsters may have negative effects of vaccination. After all, the use of the vaccine depends not only on its acceptance among physicians, but also society as a whole, which may run up against religious and moral hurdles that could be handled through campaigns highlighting the risks associated with HPV infections and the benefits of vaccination13. It is thus vital for healthcare practitioners, schools and the media to adopt a pro-active stance towards running campaigns and dealing assertively with social prejudices that might hamper young people´s access to vaccines.

As this is the time when youngsters become sexually active, with higher risks of infection, it is vital that these youngsters be properly informed about sexually transmitted diseases (STD), their transmission and prevention, especially infections such as HPV that may have severe consequences such as cervical, penile, anal and oropharyngeal cancers 14. Furthermore, it is also crucially important to run campaigns that encompass the male public because, as demonstrated in this study, their knowledge levels are lower than among their female counterparts, seemingly unaware of the risks of infection and their possible role in spreading the virus.


Most youngsters had already heard about the vaccine, although less than half of them knew that both boys and girls may be vaccinated. About half of the female respondents mentioned that they had already been vaccinated, with only 5% of the boys reported that they had done so. Furthermore, information from physicians was mentioned mainly by the female segment.

As boys presented lower levels of knowledge than girls, this indicates that healthcare policies must encompass both genders, striving to provide information and heighten awareness among the population of the importance of HPV vaccination.


We offer our thanks to the directors, teachers and employees of the UNIVALI Laboratory School (CAU), as well as the parents and pupils involved directly or indirectly in this research project.


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