Principale Preventive Medicine Knowledge about infection with human papillomavirus: A systematic review

Knowledge about infection with human papillomavirus: A systematic review

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Volume:
46
Anno:
2008
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english
DOI:
10.1016/j.ypmed.2007.09.003
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Available online at www.sciencedirect.com

Preventive Medicine 46 (2008) 87 – 98
www.elsevier.com/locate/ypmed

Knowledge about infection with human papillomavirus: A systematic review
Stefanie J. Klug ⁎, Meike Hukelmann, Maria Blettner
Institute of Medical Biostatistics, Epidemiology and Informatics, Hospital of the University of Mainz, 55101 Mainz, Germany
Available online 14 September 2007

Abstract
Objective. Human papillomavirus (HPV) is a necessary cause of cervical cancer and genital warts. The aim of this systematic literature review
was to provide an overview of knowledge about HPV infection among the public, students, patients and health professionals.
Method. PubMed searches were performed and the results of studies were reported by age, gender, study population, country, recruitment score
and year of study conduct. The recruitment score covered the mode of recruitment, study size and response rate.
Results. We included 39 studies published between 1992 and 2006 covering a total of 19,986 participants. The proportion of participants who
had heard of HPV varied from 13% to 93%. Understanding that HPV is a risk factor for cervical cancer depended on whether the question was
closed (8–68%) or open (0.6–11%). Between 5% and 83% knew about the association of HPV and (genital) warts. HPV was often mistaken with
other sexually transmitted viruses. Health professionals and women had better knowledge about HPV than other participants.
Conclusion. Overall, the knowledge of the general public about HPV infection is poor. Efforts should be increased to give sufficient and
unbiased information on HPV infection to the general public.
© 2007 Elsevier Inc. All rights reserved.
Keywords: Health knowledge; Attitudes; Practice; Papillomavirus; Human; Cervical cancer; Genital warts; Vaccines; Review

Introduction
Infection with human papillomavirus (HPV) is one of the
most common sexually transmitted infections (Braly, 1996).
More than 100 different HPV types have been described, about
30 of which infect the genital;  system (de Villiers et al., 2004).
High-risk types of HPV are a necessary cause of cervical cancer
(zur Hausen, 1991; Munoz et al., 1992; Schiffman et al., 1993;
Walboomers et al., 1999; Munoz et al., 2003; Cogliano et al.,
2005), which is the second commonest cancer in women worldwide (Ferlay et al., 2004). Additionally, some low-risk HPV
types cause considerable morbidity by causing benign genital
warts (Trottier and Franco, 2006).
In the USA in 2000, only 2% of persons aged 18 and older
named “HPV” or “human papillomavirus” when asked what
sexually transmitted diseases they knew, and only 28% had heard
of HPV (The Kaiser Family Foundation, 2000). We performed a
population-based survey in Bielefeld, Germany, in 2000 and found
that knowledge about the risk factors for cervical cancer was poor.
Only 3.2% of the participants (women aged 25–75) named
⁎ Corresponding author. Fax: +49 6131 172968.
E-mail address: klug@imbei.uni-mainz.de (S.J. Klug).
0091-7435/$ - see front matter © 2007 Elsevier Inc. All rights reserved.
doi:10.1016/j.ypmed.2007.09.003

“HPV”, “papillomavirus” or “virus” as a risk factor, and only 1.5%
had heard of “HPV” or “papillomavirus” (Klug et al., 2005).
A quadrivalent vaccine against HPV 6, 11, 16 and 18 has been
approved in 2006 by the US Food and Drug Administration, the
European Medicines Agency and other official agencies around the
world. Avaccine that protects against HPV 16 and 18 is expected to
be licensed in the near future (Arbyn and Dillner, 2007). Both
prophylactic vaccines against HPV have been assessed in large
clinical trials and have been shown to be well tolerated and
efficacious (Koutsky et al., 2002; Harper et al., 2004; Villa, 2005;
Arbyn and Dillner, 2007; Kaufmann and Schneider, 2007).
There is evidence that acceptance of HPV vaccination is
increased when parents or young women were well informed
about the risks and benefits (Kahn et al., 2003; Davis et al.,
2004), although this was not found consistently (Dempsey et al.,
2006). If women are tested for HPV infection in the frame of
cervical cancer screening, it is important that they receive
adequate information on HPV and that they understand the
implications of an HPV infection (Cuzick et al., 2006).
We performed a systematic review of various literature
databases to determine knowledge about HPV infections and
HPV as a risk factor for cervical cancer. The results of all the
studies included are presented by age and gender, by study

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S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

population, by country, by recruitment score and by year of
study conduct in order to determine further needs for education
on and prevention of HPV infection.

ages (15 years and above). In addition, studies were categorized according to the
selection of participants: the general public, students, patients and health professionals, the latter including physicians, nurses, nurse practitioners and teachers of
health courses. An attempt was made to analyze physicians separately.

Methods

Response rate

Search strategy

Information on participation was abstracted from each publication. For
comparison, the response rate in each study was recalculated, when possible,
with the formula of Slattery et al. (1995). In some publications, however, the
numbers for non-participation (refusal, not eligible, not contacted) were not
listed separately or remained unclear. If the data necessary for recalculation were
not available, the participation rates given in the publication were extracted. If
no proportion for participation was given or could be recalculated, the response
rate was classified as missing.

Literature searches in PubMed (last updated April 2007) were conducted
with 11 combinations of keywords: “HPV attitudes”, “HPV attitude”, “HPV
knowledge”, “HPV health knowledge”, “HPV education”, “HPV practice”,
“HPV health practice”, “HPV health education”, “HPVawareness”, “HPVethnic
groups” and “HPV health behavior”. Replacing the term “HPV” by
“papillomavirus” yielded additional publications. In total, 108 publications
were identified from PubMed, and six further publications were found in the
reference lists of these publications. The psychological database PsyDok was
searched with the keywords “HPV” and “papillomavirus”, but no publications
were found.

Inclusion criteria
All studies of knowledge about the existence of HPV, about HPV as a risk
factor for cervical cancer, about the symptoms of an HPV infection and about
transmission of HPV were included if published before January 2007. No
limitations were applied on study size, study population or country in which they
were conducted.

Recruitment score
We attempted to assess the quality of recruitment of the study sample and
also used this information as a surrogate for potential selection bias on the basis
of strict epidemiological criteria. Scores were calculated for three categories:
recruitment of participants, response rate and number of study subjects (Fig. 1).
The scores from the three categories were added, yielding scores classified as:
low, zero to four points; medium, five to eight points; and high, nine to twelve
points. No recruitment score was assigned to studies based on health professionals or focus groups.

Statistical methods
Exclusion criteria
We excluded case reports, general reviews, letters to the editor, editorials and
articles in languages other than English. Studies in which participants were
given basic information before they answered the questionnaire and studies that
resulted in general knowledge scores were also excluded.

Linear regression was performed to examine the association between year of
study conduct and knowledge of HPV infection. Spearman's correlation
coefficient and the corresponding p value were calculated. All p values were
two-sided and considered statistically significant if below 0.05. This was an
exploratory analysis.

Categorization of studies

Results

The studies were divided into four groups according to the age and gender of
the study subjects. Group 1 comprised all studies of women up to the age of
30 years, also including studies of female students with no indication of age and
some female students over 30. Group 2 comprised studies of women of all ages
(13 years and above). Group 3 comprised studies of young men and women up to
the age of 30 years, also including studies of students with no indication of age
and some students over 30. Group 4 comprised studies of men and women of all

Overall, 114 articles dealing with knowledge about HPV
were identified, of which 75 were excluded for the following
reasons: knowledge questions not fitting our inclusion criteria
(eight); focus groups without quantitative data (13); general
reviews, reports of another publication, letters to the editor or
editorials without original data (23); case report (one); language

Fig. 1. The recruitment score consists of three items: mode of recruitment, response rate and study size.

Table 1
Characteristics of 39 studies on knowledge about HPV infection published between 1992 and 2006 involving 19,986 total participants
Reference

Study region, country

Year(s) of study Age (years)
conduct

Gender

Ethnicity

Survey instrument

Number of
participants

Study population

Recruitment

Response rate

Vail-Smith and
White (1992)
Linnehan et al.
(1996)

Southeast, USA

1989

Mostly 18–23

Female

100%

≥ 25

Female
and male

All eligible college-based
health centers

53%

Martinez et al. (1997)

Orange County, USA

1991–1992

42 (mean)

30

1995

≥ 25

Questionnaire assumed
to be sent by mail

444

Ramirez et al. (1997)

Not specified, USA

1992

18–22

Female

Eastern Cape,
South Africa

1997 a

15–40

Female

Questionnaire filled
in at appointment or
dormitory floor meeting
Questionnaire distributed
in residences

110

Buga (1998)

54% Caucasian,
16% Asian,
13% Hispanic
Not specified

260

University students

Hasenyager (1999)

Not specified, USA

1996–1997

18–57

Female

Not specified

Questionnaire filled
in at doctor's visit

154

Yacobi et al. (1999)

Florida, USA

1996

25 (median)

81% Caucasian

Questionnaire sent by mail

289

Baer et al. (2000)

New England, USA

1996 a

≥ 18

76% Caucasian, 16% Asian

Questionnaire sent by mail

322

Dell et al. (2000)

Toronto, Canada

1999 a

≥ 15

Mixed

Hoover et al. (2000)
Mays et al. (2000)

New Jersey, USA
Chicago and
Indianapolis, USA

1998
1998 a

Questionnaire filled
in during class
Face-to-face interview
Face-to-face interview

Lambert (2001)

New York, USA

Not available

15–28
14–18
(Indianapolis)
20–50
(Chicago)
≥ 18

Female
and male
Female
and male
Female
and male
Female
Female

Patients at university health center;
students, eligible if presenting
for yearly gynecological examinations
University students

Apparently
convenience sample
Random sample from
Australian Medical
Publishing Company
national database
All eligible students,
additional
convenience sample
Convenience sample
(every second, but
next one if person refused)
Not clearly stated

Not available

Victoria, Australia

60% Caucasian,
20% Asian, 10% Latino
Not specified

Face-to-face interview

Mulvey et al. (1997)

Female
and male
Female
and male

University students enrolled
in health courses
Physicians or nurse practitioners able to
diagnose and treat HPV, working at
college-based health center with an
undergraduate population of at least
3400; physician assistants excluded
Physicians based at University of
California, Irvine, and community of Irvine
Registered general practitioners,
excluded if over the retirement age
of 65 or with fewer than 1500
consultations per year
University students

Random sample

1994 a

Questionnaire answered
on computer sheet
Questionnaire by mail

263

Not specified, USA

90% Caucasian,
8% African American
Not specified

Not specified

Lazcano-Ponce
et al. (2001)
Wardle et al. (2001)

Cuernavaca, Mexico

1998

15–49

Female
and male
Female

3.2% or 35% b,c

99%

First-year university students

523

Senior high school students

Convenience sample

Not available

60
20 Indianapolis,
20 Chicago

Young women at the beach
Patients in waiting rooms at health
clinics, low socioeconomic status

Convenience sample
Convenience sample

Not available
Not available

60

Students at private college

Convenience sample

100% e

Not specified

Questionnaire filled in
during class
Face-to-face interview

880

Population-based sample of households

Population-based random sample

86%

Not specified

Interview

3693

Population-based sample

Population-based random sample

Not available

95% Caucasian
Not specified

Questionnaire sent by mail
Questionnaire sent by mail

400
108

All eligible employees
Not stated

41%
Not available

Mainly Caucasian

Questionnaire
sent by mail
Questionnaire
sent by mail
Questionnaire filled
in at doctor's visit

163

University employees
Teachers and nurses from high
school and middle school
Population-based sample

54%

222

University students

Population-based random
sample
Random sample

1032

Women attending a clinic

About 80% d

Questionnaire filled
in at focus group

48

Low-income and minority women

Women during a certain
time period in selected clinic
sessions, unclear if
consecutive
Focus group

Questionnaire filled in
during routine
gynecological check-up,
before lecture on
risk factors for cervical
cancer or during class

162

Women presenting to general
practitioners for a routine
gynecological check-up; women
attending lecture on risk factors for
cervical cancer, class of students in
third year of biomedical science

Convenience sample

Not available

97% Caucasian
75% Caucasian (Indianapolis);
95% African
American (Chicago)

1999
2000
2000

a

Gudmundsdottir
et al. (2003)
Philips et al. (2003)

Reykjavik, Iceland

2001

18–23

Female
and male
Female
Female
and male
Female

Nottingham, England

Not available

18–23

Female

94% Caucasian

Waller et al. (2003)

London, England

2000–2002

≥ 16

Female

84% Caucasian

Anhang et al. (2004)

Not specified, USA

2002

18–81

Female

Baay et al. (2004)

Antwerp, Belgium

2003

39.6 (mean)

Female

40% Caucasian,
44% Hispanic,
13% African American
Not available

22% b

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

74% d

58% b

Not specified,
United Kingdom
Pitts and Clarke (2002) Northwest England
Beatty et al. (2003)
Vermont, USA

19–64
Not available

79% b,c

Random sample provided
by registrar's office
All eligible students

a

16 and above

143

44% b

Not applicable

89

(continued on next page)

90

Table 1 (continued)
Reference

Study region, country

Year(s) of study
conduct

Age (years)

Gender

Ethnicity

Survey instrument

Number of
participants

Study population

Recruitment

Response rate

Boardman et al.
(2004)

Providence, USA

2001

13–63

Female

Face-to-face interview

250

Patients at colposcopy clinic, cancer
patients excluded

Consecutive patients

Not available

Holcomb et al.
(2004)
Lai et al. (2004)

Not specified, USA

2001

≥18
Not available

Patients at local university health
service and family practice clinics
Vietnamese physicians in northern
California invited to education seminar

Convenience sample of
consecutive patients
Not clearly stated

About 80% d

2001

Questionnaire filled in
at doctor's visit
Questionnaire filled in
at education seminar

289

Northern California,
USA

Female
and male
Female
and male

44% Caucasian,
28% Hispanic,
17% African American
71% Caucasian,
12% African American
100% Asian

Le et al. (2004)

Ottawa, Canada

2003 a

18–75

Female

Not specified

Face-to-face interview

100

Consecutive patients

Waller et al. (2004)

2002

≥16

Face-to-face interview

1937

1999

15–85

Female
and male
Female

93% Caucasian

Ackermann
et al. (2005)

Not specified,
United Kingdom
Düsseldorf area,
Germany

Mainly Caucasian

Questionnaire filled
in at doctor's visit

2108

Chingang et al.
(2005)

Port-of-Spain,
Trinidad and Tobago

2003 a

Not available

Female
and male

Not specified

Face-to-face interview

63

Klug et al. (2005)
Philips et al. (2005)

Bielefeld, Germany
East-central England

2000
Not available

25–75
20–64

Female
Female

Mainly Caucasian
98% Caucasian

Questionnaire sent by mail
Questionnaire
distributed at doctor's
visit or sent by mail

532
1244

Pruitt et al. (2005)

Texas, USA

2002–2003 a

18–79

Female

Face-to-face interview

175

Sharpe et al. (2005)

Southern Carolina,
USA

2002–2003

19–63

Female

46%
34%
17%
32%
68%

Women with Pap smear result of
ASCUS or LSIL seen at clinic
Population-based sample
of households
Patients at routine visit at gynecologist,
patients with known gynecological or
breast malignancy excluded
General practitioners and gynecologists
in inner Port of Spain offering
Pap smears
Population-based sample
Women eligible for cervical screening
during routine (non-screening)
consultations and women called for
screening by Nottingham
screening service
Patients and community volunteers
with abnormal Pap smear

Face-to-face interview

44

Baay et al. (2006)

Antwerp, Belgium

2004 a

Not available

Female
and male

Not available

Questionnaire distributed
during post-academic
training session and during
education at university

88

Daley et al. (2006)

Not specified, USA

2005

48 (mean)

Not available

Victoria, Australia

2004 a

18–30

Not specified, USA

2004

47 (mean)

Male
Not available
and female

Questionnaire sent
by mail or Internet
Questionnaire distributed
at doctor's visit
Questionnaire sent by mail

294

Giles and Garland
(2006)
Irwin et al. (2006)

Female
and male
Female

Massad et al. (2006)

Illinois, USA

2003–2004 a

19–65

Female

71% Caucasian, 4% Hispanic,
25% African American

Questionnaire distributed
at doctor's visit

178

Moreira et al. (2006)

Salvador City, Brazil

2002

16–23

Female

2% white, 26% black,
73% mixed

Face-to-face interview

204

Not available

All information was taken from original publications, except response rate which was recalculated wherever possible.
a

Information obtained from authors.

b

Number of subjects excluded because of incomplete questionnaire unknown.

c

Number of ineligible subjects unknown.

d

From publication.

e

100% response rate was achieved because questionnaires were distributed in a classroom and filled in directly.

f

Number of subjects who could not be contacted unknown.

60
2980

Patients at primary health clinics,
diagnosed high-risk HPV positivity,
abnormal Pap smear
General practitioners during
post-academic training session
not concerning cervical cancer, general
practitioners still in training coming
back to university for further education
US pediatrician network, excluded if
spending b 50% of their time in primary care
Women attending a local university health
service or cervical dysplasia clinic
US clinician database (physicians,
nurse midwives, nurse practitioners,
physician assistants) in specialties that
often offer Pap screening (gynecology
and obstetrics; family, general,
internal or adolescent medicine)
Women attending colposcopy clinics for
evaluation of abnormal cytology;
low socioeconomic status
Women in waiting room of
gynecological clinic; low
socioeconomic status

Population-based
random sample
Women visiting 23
office-based gynecologists

Not available
(only those attending
education seminar)
75% d
71%
73% c

All eligible

100% (of those who
could be reached) f

Population-based random sample
Women visiting 20
general practitioners
and random sample of
women called for screening

36%
28% b,c

Convenience sample

Not available

Convenience sample

Not available

Convenience sample

100% e

All eligible

68% b

Convenience sample

Not available

Random sample

70%

Consecutive patients

Not available

Consecutive sample

86%

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

Caucasian,
Hispanic,
African American
Caucasian,
African American

34

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

91

other than English (four); basic information about HPV given to
participants before or during filling in the questionnaire (seven);
data presentation inadequate for our review (eight); no
examination of knowledge items (nine); and second publication
on the same study (two). A total of 39 articles published
between 1992 and 2006 met the inclusion criteria, did not fulfill
any of the exclusion criteria and were therefore included in this
systematic review (Table 1). In total, 19,986 participants were
surveyed. The size of the studies differed substantially, and
different modes of recruitment were used. The response rate
varied from 3% to 100%. Most of the studies were conducted in
the USA (20) and the United Kingdom (6).

participants had heard of HPV, of women of all ages (group 2),
15–31% had heard of HPV. Between 10 and 85% of the study
participants knew that infection with HPV can be asymptomatic. More than two thirds of young women (group 1) knew that
HPV is a sexually transmitted infection.
Three studies were identified in which the results presented
were restricted to participants who had heard of HPV (Baer
et al., 2000; Waller et al., 2003; Holcomb et al., 2004) (data not
shown). In these studies, 40% of women of all ages (group 2)
confirmed the statement that HPV is the main cause of cervical
cancer (Waller et al., 2003), and 18–72% knew that HPV is
sexually transmitted.

Knowledge about HPV infection

Knowledge about HPV and cervical cancer

Knowledge about HPV infection varied widely within the
groups and according to the questions asked (Table 2). In
studies including young women (group 1), 13–93% of study

The association between HPV and cervical cancer was
known by 8% to 68% of study participants of different age and
gender (group 1 to group 4) if different possible answers were

Table 2
Knowledge about HPV infection by age and gender (health professionals excluded), reported in 25 studies
Question

Heard of HPV…

HPV as a risk factor for cervical
cancer was known by…
(closed question)

Young women
(group 1)

Women of all ages
(group 2)

Young men and women
(group 3)

Men and women of all
ages (group 4)

% (reference)

% (reference)

% (reference)

% (reference)

13 (Vail-Smith and White, 1992)
20 (Mays et al., 2000)
23 (Hoover et al., 2000)
25 (Waller et al., 2003)
31 (Philips et al., 2003)
73 (Giles and Garland, 2006) a
93 (Giles and Garland, 2006) b
8 (Vail-Smith and White, 1992) c
10 (Moreira et al., 2006) c
16 (Baer et al., 2000)
33 (Giles and Garland, 2006) a
34 (Gudmundsdottir et al., 2003)
44 (Ramirez et al., 1997)
49 (Hasenyager, 1999)
51 (Philips et al., 2003)
55 (Boardman et al., 2004)
57 (Giles and Garland, 2006) b
68 (Buga, 1998)

15 (Mays et al., 2000)
27 (Anhang et al., 2004)
30 (Pitts and Clarke, 2002)
31 (Waller et al., 2003)

13 (Dell et al., 2000)
38 (Yacobi et al., 1999)

47 (Pruitt et al., 2005)
51 (Philips et al., 2005)
57 (Boardman et al., 2004)

13 (Baer et al., 2000)
27 (Yacobi et al., 1999)
53 (Lambert, 2001)

HPV as risk factor for cervical
cancer was named by…
(open question)

Participants who knew that HPV
can be asymptomatic

Participants who knew that HPV
is sexually transmitted

a

10 (Vail-Smith and White, 1992)
27 (Ramirez et al., 1997)
63 (Giles and Garland, 2006) a
73 (Giles and Garland, 2006) b
47 (Boardman et al., 2004)
63 (Gudmundsdottir et al., 2003)
67 (Moreira et al., 2006)
83 (Giles and Garland, 2006) b
84 (Ramirez et al., 1997)
87 (Giles and Garland, 2006) a

0.9 (Waller et al., 2004)
1.5 (Klug et al., 2005) d
1.9 (Lazcano-Ponce et al., 2001)
3.1 (Baay et al., 2004)
11 (Pitts and Clarke, 2002)
17 (Pitts and Clarke, 2002)
66 (Pruitt et al., 2005)

39 (Holcomb et al., 2004)

0.6 (Waller et al., 2004)

10 (Yacobi et al., 1999)
85 (Lambert, 2001)

30 (Pitts and Clarke, 2002)
47 (Boardman et al., 2004)
70 (Pruitt et al., 2005)

Women attending local university health service.
Women attending cervical dysplasia clinic.
c
Closed question assumed, but not clearly stated.
d
In the publication, 3.2% was given which also included the word “virus”. Here, only “HPV” and “papillomavirus” were considered for comparability with the other
studies.
b

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S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

pregiven and there was multiple choice (closed questions)
(Table 2). When this knowledge was assessed using an open
question, it was consistently lower (0.6–11%).
Le and colleagues (2004) reported that 75% of women with
an abnormal Pap smear had no or minimal knowledge of the
role of HPV in the development of cervical cancer (data not
shown).
When study results were grouped by study population, a
wide range of knowledge was found within the groups of
students and patients (Table 3). Of the four studies with a
population base, three used an open question to assess knowledge on HPV as a risk factor for cervical cancer (Lazcano-Ponce
et al., 2001; Waller et al., 2004; Klug et al., 2005), and
knowledge in the population was low (0.6–1.9%). Gudmundsdottir and colleagues used a closed question and 34% of the
study population knew that HPV is a risk factor for cervical
cancer (Gudmundsdottir et al., 2003).
Nine studies addressed the knowledge of physicians, nurses
and teachers of health courses about HPV infections (Table 1).
Health professionals had considerably more knowledge than the
other groups (Table 3). Between 82–100% and 59–87% of
physicians knew that HPV is a risk factor for cervical cancer when
a closed and open question was used, respectively (Linnehan

et al., 1996; Martinez et al., 1997; Lai et al., 2004; Chingang et al.,
2005; Irwin et al., 2006; Baay et al., 2006). The 100% knowledge
was obtained in a group of motivated physicians right before
attending a seminar on cervical cancer topics (Lai et al., 2004).
Additionally, 96% of experienced general practitioners with more
than 1500 consultations per year knew that HPV is the sexually
transmitted infection most commonly associated with cervical
cancer (Mulvey et al., 1997). Half of these general practitioners
saw patients with an STD at least once a month. In a study of US
pediatricians, 68% knew that almost all cervical cancers are
caused by HPV infection, while only 20% knew that genital warts
are not caused by the same HPV types that cause cervical cancer
(Daley et al., 2006).
Teachers and nurses in middle and high schools in the USA
had less knowledge than physicians. Only half approved the
sentence that HPV was found in the cervices of most women
with cervical cancer, and only 33% denied that most women
with HPV will develop cervical cancer (Beatty et al., 2003).
Knowledge about HPV by country
Most studies have been performed in the USA and there was
a wide range of knowledge (Table 4). No differences between

Table 3
Knowledge about HPV infection by participant group, reported for 28 studies
Question

Heard of HPV…

Students

Patients

Physicians

Population-based

% (reference)

% (reference)

% (reference)

% (reference)

13 (Vail-Smith and White, 1992)
13 (Dell et al., 2000)
31 (Philips et al., 2003)
38 (Yacobi et al., 1999)
73 (Giles and Garland, 2006) a
HPV as a risk factor for cervical 8 (Vail-Smith and White, 1992) b
cancer was known by…
13 (Baer et al., 2000)
(closed question)
27 (Yacobi et al., 1999)
33 (Giles and Garland, 2006) a
44 (Ramirez et al., 1997)
49 (Hasenyager, 1999)
51 (Philips et al., 2003)
53 (Lambert, 2001)
68 (Buga, 1998)
HPV as a risk factor for cervical
cancer was named by…
(open question)
Participants who knew that HPV 10 (Vail-Smith and White, 1992)
can be asymptomatic
10 (Yacobi et al., 1999)
27 (Ramirez et al., 1997)
63 (Giles and Garland, 2006) a
85 (Lambert, 2001)
Participants who knew that HPV 84 (Ramirez et al., 1997)
is sexually transmitted
87 (Giles and Garland, 2006) a

a

18 (Mays et al., 2000)
31 (Waller et al., 2003)
93 (Giles and Garland, 2006)

10 (Moreira et al., 2006) b
39 (Holcomb et al., 2004)
47 (Pruitt et al., 2005)
51 (Philips et al., 2005)
57 (Boardman et al., 2004)
57 (Giles and Garland, 2006)

82 (Chingang et al., 2005) b, c 34 (Gudmundsdottir et al., 2003)
92 (Chingang et al., 2005) b, d
97 (Linnehan et al., 1996) e
98 (Irwin et al., 2006)
100 (Lai et al., 2004)

59 (Baay et al., 2006)
87 (Martinez et al., 1997)

0.6 (Waller et al., 2004)
1.5 (Klug et al., 2005) f
1.9 (Lazcano-Ponce et al., 2001)

66 (Pruitt et al., 2005)
83 (Daley et al., 2006)
73 (Giles and Garland, 2006) 97 (Irwin et al., 2006)

47 (Boardman et al., 2004)
67 (Moreira et al., 2006)
70 (Pruitt et al., 2005)
83 (Giles and Garland, 2006)

63 (Gudmundsdottir et al., 2003)

Women attending local University Health service.
Closed question assumed, but not clearly stated.
c
General practitioners.
d
Gynecologists.
e
Including nurse practitioners.
f
In the publication, 3.2% was given which also included the word “virus”. Here, only “HPV” and “papillomavirus” were considered for comparability with the other
studies.
b

Table 4
Knowledge about HPV infections in different countries (health professionals excluded), reported for 25 studies
Question

Heard of HPV…

United Kingdom

Australia

Canada

Brazil

Iceland

South Africa

Germany

Mexico

Belgium

% (reference)

% (reference)

% (reference)

% (reference)

% (reference)

% (reference)

% (reference)

% (reference)

% (reference)

13 (Vail-Smith and
White, 1992)
18 (Mays et al., 2000)

30 (Pitts and
Clarke, 2002)
31 (Philips
et al., 2003)
31 (Waller
et al., 2003)

73 (Giles and
Garland, 2006) a
93 (Giles and
Garland, 2006) b

13 (Dell et al., 2000)

51 (Philips
et al., 2005)
51 (Philips
et al., 2003)

33 (Giles and
Garland, 2006) a
57 (Giles and
Garland, 2006) b

10 (Moreira
et al., 2006) c

34 (Gudmundsdottir
et al., 2003)

68 (Buga, 1998)

1.5 (Klug et al., 2005) d

1.9 (Lazcano-Ponce
et al., 2001)

3.1 (Baay
et al., 2004)

23 (Hoover et al., 2000)

HPV as a risk factor for
cervical cancer was
known by…
(closed question)

27 (Anhang et al., 2004)
38 (Yacobi et al., 1999)
8 (Vail-Smith and
White, 1992) c
13 (Baer et al., 2000)
27 (Yacobi et al., 1999)
39 (Holcomb
et al., 2004)
44 (Ramirez et al., 1997)
47 (Pruitt et al., 2005)
49 (Hasenyager, 1999)
53 (Lambert, 2001)
57 (Boardman
et al., 2004)

HPV as risk factor for
cervical cancer
was named by…
(open question)
Participants who knew
that HPV can be
asymptomatic

10 (Vail-Smith
and White, 1992)
10 (Yacobi et al., 1999)

Participants who knew
that HPV is sexually
transmitted

27 (Ramirez et al., 1997)
66 (Pruitt et al., 2005)
85 (Lambert, 2001)
47 (Boardman
et al., 2004)
70 (Pruitt et al., 2005)

0.6 (Waller
et al., 2004)
11 (Pitts and
Clarke, 2002)
17 (Pitts and
Clarke, 2002)

30 (Pitts and
Clarke, 2002)

63 (Giles and
Garland, 2006) a
73 (Giles and
Garland, 2006) b

83 (Giles and
Garland, 2006) b
87 (Giles and
Garland, 2006) a

67 (Moreira
et al., 2006)

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

USA
% (reference)

63 (Gudmundsdottir
et al., 2003)

84 (Ramirez et al., 1997)
a
b
c
d

Women attending local university health service.
Women attending cervical dysplasia clinic.
Closed question assumed, but not clearly stated.
In the publication, 3.2% was given which also included the word “virus”. Here, only “HPV” and “papillomavirus” were considered for comparability with the other studies.

93

94

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

countries were observed, however, no formal statistical test was
performed since the numbers of studies were small for most
countries, except USA and United Kingdom.

Table 6
Results from three studies on knowledge about HPV infection, stratified for
women and men
Question

Women Men All p value for difference
(%)
(%) (%) between men and
women (χ2 test) a

Heard about HPV infection of the
cervix… (Baer et al., 2000)
HPV as risk factor for cervical
cancer was selected by…
(closed question)
(Baer et al., 2000)
HPV as risk factor for cervical
cancer was named by… (open
question) (Waller et al., 2004)
Viruses or infection as risk factor
for cervical cancer were named
by… (Wardle et al., 2001)
Participants who knew that HPV
is transmitted by skin-to-skin
contact during intercourse
(Baer et al., 2000) b

35

29

33

16

5

13

Knowledge about HPV and genital warts
Knowledge about HPV and genital warts was examined in
13 studies (Table 5). The existence of genital warts was well
known among most study participants. More than 88% had
heard of genital warts (Ramirez et al., 1997; Mays et al.,
2000; Baer et al., 2000; Holcomb et al., 2004), and 5–42%
of study participants knew that HPV can cause them (Baer
et al., 2000; Holcomb et al., 2004; Boardman et al., 2004;
Pruitt et al., 2005; Moreira et al., 2006). Sharpe et al. (2005)
found that 45% of women with high-risk HPV infection
confirmed that some types of HPV cause genital warts. When
asked if there is a relation between genital warts and cervical cancer, 34% answered “no” (Waller et al., 2003), while
2% (Waller et al., 2004) or 10% (Baer et al., 2000) named
genital warts or “wart virus” as a risk factor for cervical
cancer.

a
b

0.9

0.2

Not statistically
significant
p b 0.05

0.6 Not statistically
significant

31

26

29

Not available

23

4

18

p b 0.05

Information in this column was taken from the publications.
Only of those who had heard of HPV.

Knowledge of women and men
Table 5
Knowledge about HPV and genital warts, reported for 13 studies (health
professionals excluded)
Question

Answer

Heard of genital warts… Yes
No
Which STDs can
you recall?
Does HPV cause
genital warts?

Genital warts
Yes

Some types of HPV
Yes
cause genital warts
What are the symptoms Warts in women
of HPV?
Warts in men
Genital warts

What do you know
about HPV?

How can genital warts
be transmitted?

a
b
c
d

% of subjects
88 (Mays et al., 2000)
96 (Baer et al., 2000)
8 (Ramirez et al., 1997)
12 (Holcomb et al., 2004)
15 (Mays et al., 2000)
5 (Moreira et al., 2006)
9 (Baer et al., 2000) a
38 (Holcomb et al., 2004)
42 (Boardman et al., 2004)
42 (Pruitt et al., 2005)
45 (Sharpe et al., 2005) b

83 (Ramirez et al., 1997)
56 (Ramirez et al., 1997)
5 (Vail-Smith and White, 1992)
5 (Pitts and Clarke, 2002)
70 (Giles and Garland, 2006) d
83 (Giles and Garland, 2006) c
Warts/warty growth 28 (Holcomb et al., 2004)
30 (Yacobi et al., 1999)
Genital warts
8 (Pitts and Clarke, 2002)
22 (Gudmundsdottir
et al., 2003)
Warts
3 (Pitts and Clarke, 2002)
Skin-to-skin contact 63 (Baer et al., 2000) a
during intercourse
Oral sex
49 (Baer et al., 2000) a
Exchange of bodily 42 (Baer et al., 2000) a
fluid (blood, semen)

Only students who had heard of genital warts.
High-risk HPV positive women only.
Women attending local university health service.
Women attending cervical dysplasia clinic.

The results of three studies were reported stratified by gender
(Baer et al., 2000; Wardle et al., 2001; Waller et al., 2004).
Women had better knowledge about HPV than men and knew
significantly more often that HPV is a risk factor for cervical
cancer (Table 6). Women had heard about HPV infections of the
cervix more often and knew significantly more often that HPV
is transmitted by skin-to-skin contact (Baer et al., 2000).
Knowledge by education
Four studies addressed the issue of whether knowledge about
HPV infection depends on the educational level (data not
shown). The results were inconsistent: while one study found no
significant difference (Waller et al., 2003), three others did
(Waller et al., 2004; Philips et al., 2005; Moreira et al., 2006).
Knowledge and quality of recruitment
The recruitment score was applied to 29 studies so that the
results could be stratified by quality of recruitment (Fig. 1). A
low score for quality of recruiting was found for 12 studies, a
medium score for 14 and a high score for 3. Studies with the
highest percentage of knowledge scored lower in the recruitment score than the other studies regarding the respective
question (Table 7).
Knowledge by year of study conduct
Linear regression was performed to examine the influence of
the year of study conduct on knowledge of HPV infection
(Fig. 2). We included six studies of knowledge about HPV as a
risk factor for cervical cancer (closed question), which were

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

95

Table 7
Knowledge about HPV infection stratified by recruitment score, reported for 24 studies (health professionals and focus group studies excluded)
Question

Heard of HPV…

HPV as a risk factor for cervical
cancer was known by…
(closed question)

HPV as risk factor for cervical
cancer was named by…
(open question)
Participants who knew that HPV
can be asymptomatic

Participants who knew that HPV
is sexually transmitted

Low score

Medium score

High score

% (reference)

% (reference)

% (reference)

13 (Dell et al., 2000)
18 (Mays et al., 2000)
23 (Hoover et al., 2000)
73 (Giles and Garland, 2006) a
93 (Giles and Garland, 2006) b
33 (Giles and Garland, 2006) a
39 (Holcomb et al., 2004)
44 (Ramirez et al., 1997)
47 (Pruitt et al., 2005)
49 (Hasenyager, 1999)
53 (Lambert, 2001)
57 (Giles and Garland, 2006) b
68 (Buga, 1998)
3.1 (Baay et al., 2004)

13 (Vail-Smith and White, 1992)
30 (Pitts and Clarke, 2002)
31 (Philips et al., 2003)
31 (Waller et al., 2003)
38 (Yacobi et al., 1999)
8 (Vail-Smith and White, 1992) c
10 (Moreira et al., 2006) c
13 (Baer et al., 2000)
27 (Yacobi et al., 1999)
34 (Gudmundsdottir et al., 2003)
51 (Philips et al., 2003)
51 (Philips et al., 2005)
57 (Boardman et al., 2004)
1.5 (Klug et al., 2005) d
11 (Pitts and Clarke, 2002)

0.6 (Waller et al., 2004)
1.9 (Lazcano-Ponce et al., 2001)

27 (Ramirez et al., 1997)
63 (Giles and Garland, 2006) a
66 (Pruitt et al., 2005)
73 (Giles and Garland, 2006) b
85 (Lambert, 2001)
70 (Pruitt et al., 2005)
83 (Giles and Garland, 2006) b
84 (Ramirez et al., 1997)
87 (Giles and Garland, 2006) a

10 (Vail-Smith and White, 1992)
10 (Yacobi et al., 1999)
17 (Pitts and Clarke, 2002)

30 (Pitts and Clarke, 2002)
47 (Boardman et al., 2004)
63 (Gudmundsdottir et al., 2003)
67 (Moreira et al., 2006)

The recruitment score was applied to 29 studies; however, only the results of 24 studies fitted into the tabular presentation.
a
Women attending local university health service.
b
Women attending cervical dysplasia clinic.
c
Closed question assumed, but not clearly stated.
d
In the publication, 3.2% was given which also included the word “virus”. Here, only “HPV” and “papillomavirus” were considered for comparability with the
other studies.

assigned a medium recruitment quality score, the highest score
available in this category. Two studies were excluded due to
missing values for year of study conduct (Philips et al., 2003,
2005). The year of study conduct was positively correlated with
knowledge, but the correlation was poor (Spearman's correlation coefficient = 0.38) and the p value showed no statistical
significance (p = 0.45).

women at a beach, 47% were willing to participate in a trial with
three vaccinations (Hoover et al., 2000). In population-based
studies, 61% of women were willing to participate (Gudmundsdottir et al., 2003), and 84% of women would allow their
adolescent daughter to be immunized in a trial after they had
learned of the possibility of preventing cervical cancer (LazcanoPonce et al., 2001).

Confusion with other sexually transmitted infections

Discussion

There was substantial mixing up of HPV with human
immunodeficiency virus (HIV) and herpes simplex virus (data
not shown) (Ramirez et al., 1997; Yacobi et al., 1999; Dell et al.,
2000; Baer et al., 2000; Holcomb et al., 2004; Pruitt et al.,
2005). Only 47% and 64% of the participants denied that HPV
was related to the “AIDS virus” (HIV) (Ramirez et al., 1997;
Pruitt et al., 2005). In two other studies, 20% of the participants
thought that herpes was a symptom of an HPV infection and
67% were unsure about it (Yacobi et al., 1999; Holcomb et al.,
2004).

In the 39 studies in this systematic review, 13–93% of
participants had heard of HPV. Three predictors for knowledge
about HPV infections were identified.
The first was the type of question asked: in multiple choice
(closed) questions, HPV was identified as a risk factor for cervical
cancer by 8–68% of participants, while in open questions in
which participants were asked to name risk factors for cervical
cancer, only 0.6–11% answered “HPV” or “papillomavirus”. The
long controversy on use of open or closed questions in surveys
was largely resolved in practice in favor of the closed form, which
are more efficient for interviewing, coding and analysis (Schuman
and Presser, 1979). There are, however, good arguments against
closed questions as study subjects are likely to be influenced by
the alternative answers given and prone to guessing (Schuman
and Presser, 1979; Vinten, 1995). Open questions are preferable if

Willingness to participate in an HPV vaccination trial
Willingness to participate in an HPV vaccination trial was
examined in three studies. In a convenience sample of young

96

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

Fig. 2. Linear regression was performed for knowledge about “HPV as risk
factor for cervical cancer” (closed question) by year of study conduct for six
studies with medium level recruitment score.

a group of subjects whose knowledge is unknown or highly
variable is investigated (Vinten, 1995). A more valid picture of
knowledge is obtained if the subjects must produce an answer
themselves (Schuman and Presser, 1979). In this review, only
physicians showed a high percentage of knowledge in response to
an open question (Martinez et al., 1997; Baay et al., 2006).
The second predictor was gender. In three studies in which
the results were reported stratified by gender, women had better
knowledge about HPV. Additionally, Conaglen et al. (2001)
showed that, on a general HPV knowledge score, women scored
better than men (p b 0.001). In general, gender differences in
health knowledge seem to depend on the topic. In an investigation on a specifically female topic like breastfeeding, women
had better knowledge than men (Kang et al., 2005), while men
living with HIV in the USA had better knowledge about HIV/
AIDS than women with HIV (Whetten et al., 2004).
The third predictor of HPV knowledge was profession since
59–100% of physicians knew about the relation between HPV
and cervical cancer. In some of those studies, however, the
physicians were selected from large, college-based health centers
with an undergraduate student population of at least 3400
(Linnehan et al., 1996) and from among experienced general
practitioners with more than 1500 consultations per year, half of
them diagnosing patients with sexually transmitted diseases at
least monthly (Mulvey et al., 1997). In a study of US clinicians,
most knew that HPV infection is common, chronic and often
asymptomatic, but many “were unaware of information useful for
counseling, e.g. most HPV infections clear spontaneously and
wart-and cancer-related HPV genotypes usually differ” (Irwin
et al., 2006). In a survey of general practitioners in Norway, most
considered it important to inform women about HPV and its
involvement in cervical carcinogenesis, but more than half
admitted that they had limited knowledge about HPV and did not
know where to get up-to-date information (Havnegjerde and

Thoresen, 2004). Moreover, a study among Mexican physicians
showed that only 19% knew that HPV types 16, 18, 31, 38 and 45
do not cause genital warts (Aldrich et al., 2005). Selection bias
could have led to the high knowledge level of physicians in the
studies included in this review, and there may still be a need to
provide adequate, up-to-date information about HPV to health
professionals globally, especially as they are important mediators
of knowledge.
Age was not a predictor of knowledge about HPV infection.
The results for young women (group 1) and for young men and
women (group 3) did not differ from the results for women of all
ages (group 2) or women and men of all ages (group 4). Large
differences in knowledge were found within the groups of
students and patients. However, the group of students consists
largely of young people (group 1 and group 3).
The response rates of the studies differed from 3% to 100%.
In two studies with highest response rates, questionnaires were
distributed during class, although there was one populationbased study with a response rate of 86% (Lazcano-Ponce et al.,
2001). The response rate is part of the recruitment score, which
was applied to examine methodological differences between
studies. Several studies with high percentage rates of knowledge had low recruitment scores, and selection bias, due to
study design or response rate, might be responsible for some of
those high rates. Selection bias might vary between studies,
which could explain the large difference in knowledge between
studies.
The year in which the studies were conducted ranged from
1989 to 2005. As knowledge about HPV infection in the
scientific community has increased considerably during this
time, knowledge about HPV in the general population might
have increased as well. For knowledge about HPV as a risk
factor for cervical cancer, year of study conduct was positively
associated with the level of knowledge. However, this did not
reach statistical significance and the correlation was poor. The
analysis was restricted to six studies of medium recruitment
score using a closed question.
Study limitations and strengths
This is, to our knowledge, the first systematic literature review
on the topic of knowledge about HPV infection. Our results are
important in the era of HPV testing and vaccination. Three
predictors of knowledge about HPV infection were identified, and
knowledge in different study populations was examined. A
recruitment score was assigned to assess the quality of recruitment, and knowledge within different subgroups was investigated. A large number of studies including 19,986 participants were
included.
The literature search was limited to PubMed and PsyDok
databases. Some articles might have been missed because they
were published in journals not listed in PubMed or were published in a language other than English. There was a frequent
lack of detailed information on response rate, study population
and other information in the publications.
Some studies showed that willingness to participate in an
HPV vaccination trial was quite high; however, we did not

S.J. Klug et al. / Preventive Medicine 46 (2008) 87–98

perform a systematic review on the issue and therefore cannot
give a conclusive statement on this topic.
The results of the studies were heterogeneous, and the study
designs, participants, methods, type of questions and study sizes
differed considerably. This might also explain some of the
differences in results. These large differences in study designs
and knowledge as well as the amount of missing values kept us
from calculating pooled estimates, as planned a priori.
Conclusions
This review shows that public knowledge about HPV
infection requires improvement. Providing adequate information to the general public is an important public health issue.
HPV vaccination has been taken up, and the introduction of HPV
testing into cervical cancer screening is ongoing in some
countries. Therefore, it is important that women and men
understand the implications of an HPV infection. Schools, the
media and health professionals are the main mediators for
distributing information about the prevention of cervical cancer,
and efforts should be made to improve the quality and frequency
of information given to the general public. As men have less
knowledge about HPV than women, efforts should be made to
include men in educational programs. In the future, better
knowledge on the issue is expected because of media coverage
of the introduction of HPV vaccination. There is a need for welldesigned, carefully planned and well conducted epidemiological
studies in this interdisciplinary area of research.
Acknowledgment
We thank Dr. Jochem Koenig for discussion of statistical
issues.
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