Acceptability of HPV vaccine among a national sample of gay and bisexual men.

TL;DR: HPV vaccine acceptability was high among gay and bisexual men, and these findings identify potentially important beliefs and attitudes for future communication efforts about HPV and HPV vaccine among gay or bisexual men.

Abstract: Objective: Due to higher rates of human papillomavirus (HPV) infection and anal cancer among gay and bisexual men, we aimed to characterize their willingness to get HPV vaccine and identify correlates of vaccine acceptability. Methods: We surveyed a national sample of men aged 18 to 59 who self-identified as either gay (n 236) or bisexual (n 70) during January 2009. We analyzed data using multivariate logistic regression. Results: Most men had heard of HPV vaccine (73%, 224/306) and were willing to get it (74%, 225/306). HPV vaccine acceptability was higher among men who believed their doctor would recommend getting the vaccine (OR 12.87, 95% CI: 4.63‐35.79) and those who were unsure (OR 3.15, 95% CI: 1.47‐6.76), as compared to men who believed their doctor would not recommend it. Acceptability was also higher among men who reported 5 or more lifetime sexual partners (OR 3.39, 95% CI: 1.34‐8.55), perceived greater severity of HPVrelated disease (OR 1.92, 95% CI: 1.18‐3.14), perceived higher levels of HPV vaccine effectiveness (OR 1.97, 95% CI: 1.27‐3.06), or reported higher levels of anticipated regret if they did not get vaccinated and later developed an HPV infection (OR 2.39, 95% CI: 1.57‐3.61). Conclusions: HPV vaccine acceptability was high among gay and bisexual men. These findings identify potentially important beliefs and attitudes for future communication efforts about HPV and HPV vaccine among gay and bisexual men.

Summary

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• Images are produced from the best available original document.
• Extraction into chloroform of the lanthanides, using 2,5-dimethyl-2hydroxyhexanoic acid .
• The extracted metal species is highly aggregated.

II. LANTHANIDE EXTRACTIONS

• A variety of extracting agents have been investigated for use in the solvent extraction separation of the rare earths.
• These agents can be roughly placed into the following classifications: 1) neutral phosphates, 2) acidic phosphates, 3} amines, 4) carboxylic acids, and 5) other.
• For this reason this chapter, in addition to reviewing lanthanide extractions, will discuss some of the more pertinent applications to nuclear waste processing.
• Extractant, is the liquid phase that extracts.
• Distribution ratio (D), is the ratio of the total equilibrium concentration of all f'orms o!' the substance in the e..v..taac t to total equilibrium concentration of all forms in the aqueous phase.

A. Neutral Phosphorus Agents

• Tributylphosphate (TBP) has been one of the most thoroughly studied extracting agents for the lanthanides.
• At higher acidities partial anion coextraction occurs, which lowers the separation factors (14, 15) .
• Its lanthanide separation factors are better than those of HDEHP, but problems with the coextraction of other metals has prevented its use in waste reprocessing (27) .
• Monoacidic phosphinates are also strong extracting agents.

III. CARBOXYLIC ACID LANTHANIDE EXTRACTION

• This chapter is divided into two sections.
• The first section concerns itself with the mechanisms and equilibria involved in extractions using carboxylic acids.
• The second section reviews lanthanide carboxylate extractions in detail.
• Some of the equilibria discussed in the first section have been em~loyed in the evaluation of such extractions.

A. Extraction Equilibria

• Extraction of metals by carboxylic acids involves the formation of metal carboxylates and can be represented by: (1) where the subscripts a and o denote the aqueous and organic phases, respectively.
• This assumption is not valid if: 1) the acid is appreciably soluble in the aqueous phase; 2) the acid dimerizes in the organic phase; or 3) the initial metal concentration is of the same order of magnitude as the organic acid concentration.
• When the value of x obtained from a log D vs pH plot is The extraction of a single aggresated species (MAx)J(HA)n yields the following expression: K = D[Mx+Jl-J.l[H+].
• As applied to extraction, the method consists of varying the proportions of two reacting species while keeping the s~m of the two concentrations constant and measuring the amount of extraction.
• Though useful for simple systems, the molar ratio method suffers from similar drawbacks as those inherent in the isomolar series method.

B. Extraction of Lanthanides

• In the previous chapter, a variety of extracting agents for the lanthanides was reviewed.
• In the latter, the ketone probably helps to solvate the complex.
• In a series of papers Korpusov et al. (56) and Danilov et al. (57, 58) have reported on extractions using a,adisubstituted carboxylic acids, usually containing eight or nine carbons.
• With an increase in solvent polarity, KD 0 decreased and PHA increased.
• Applying these constants , in analyzing lanthanide extractions, the extracting species were all found to be LnA 3 (HA) 3.

Comparison of log

• The hydrate number varied between one and two, but approached one at increasing lanthanide salt concentrations.
• At salt concentrations greater than 10-3 M, the extracting species may be aggregated.
• For lanthanide separations, these a,adisubstituted carboxylic acids showed better selectivity than either the naphthenic or normal carboxylic acids.
• Have been noted by Mikhailichenko" et al.
• About 300 g of crude product (45% yield) were kindly provided by the above and were recrystallized from a 1:1.

C. Acid Anion Protonation Constant

• The acid anion protonation constant was obtained from pH measurements on a series of independently prepared DMHHA c solutions, each containing a different amount of added KOH.
• This KN0 3 amount was calculated from an estimated protonation .
• In one method, the metal was re-extracted into J M HCl and then titrated with EDTA.
• Gave reasonably good analyses, but neither was well~suited for small samples.
• In some of the distribution experiments, the acid content of the aqueous phase was needed.

C. Acid Distribution Studies

• The distribution behavior of DMHHA between chloroform and water is depicted in Figure 1 , where E is defined as the ratio of the concentrations of total unionized organic acid to total unionized aqueous acid.
• As can be seen, The typical infrared spectrum of DMHHA displayed a sharp band at 2960 cm-l on top of a broad but not intense band ranging from 3~bo to 28bo ~m-1.

A. Neodymfum-DMHHA Stability Constants

• The main point of interest in most metal extraction studies is the means by which the metal extracts, that is, the nature of the extracting species.
• The aqueous phase interaction between the metal and the extracting agent should be invP.Rt1iated.
• X X Rather than studying all of the lanth~nides, one was chosen for detailed analysis in this investigation.
• The stability constant calculations will now be discussed.
• 0 X All of the quantities except the 8's are known or directly measurable.

•ment and the equation [A]= ([H]tot-[H])/~[H]. Measuring

• The pH valu~ unde~ i different conditions givea i equations.
• (At this point for further simplification, the. value of x is made equal to 3).
• This .system of i equations and 3 unknowns is solved by a least-squares multiple linear regression.
• The least-squares analysis proceeds by minimizing the sum of the squares of the individual residuals Ei.
• In a series of experiments holding the pH constant, the distribution ratios were measured.

Full text

Acceptability of HPV Vaccine Among a National Sample of Gay
and Bisexual Men
Paul L. Reiter, PHD
*,†
, Noel T. Brewer, PHD
*,†
, Annie-Laurie McRee, MPH
*
, Paul Gilbert,
MSPH
*
, and Jennifer S. Smith, PHD
*,†
*
UNC Gillings School of Global Public Health, Chapel Hill, NC
†
Lineberger Comprehensive Cancer Center, Chapel Hill, NC
Abstract
Objective—Due to higher rates of human papillomavirus (HPV) infection and anal cancer
among gay and bisexual men, we aimed to characterize their willingness to get HPV vaccine and
identify correlates of vaccine acceptability.
Methods—We surveyed a national sample of men aged 18 to 59 who self-identified as either gay
(n = 236) or bisexual (n = 70) during January 2009. We analyzed data using multivariate logistic
regression.
Results—Most men had heard of HPV vaccine (73%, 224/306) and were willing to get it (74%,
225/306). HPV vaccine acceptability was higher among men who believed their doctor would
recommend getting the vaccine (OR = 12.87, 95% CI: 4.63–35.79) and those who were unsure
(OR = 3.15, 95% CI: 1.47–6.76), as compared to men who believed their doctor would not
recommend it. Acceptability was also higher among men who reported 5 or more lifetime sexual
partners (OR = 3.39, 95% CI: 1.34–8.55), perceived greater severity of HPV-related disease (OR =
1.92, 95% CI: 1.18–3.14), perceived higher levels of HPV vaccine effectiveness (OR = 1.97, 95%
CI: 1.27–3.06), or reported higher levels of anticipated regret if they did not get vaccinated and
later developed an HPV infection (OR = 2.39, 95% CI: 1.57–3.61).
Conclusions—HPV vaccine acceptability was high among gay and bisexual men. These
findings identify potentially important beliefs and attitudes for future communication efforts about
HPV and HPV vaccine among gay and bisexual men.
Human papillomavirus (HPV) infection is widespread among males, with recent prevalence
estimates ranging up to 73%.
1-4
HPV-infected men face potentially severe health
consequences, although most infections resolve spontaneously. An estimated 63% of
oropharyngeal cancers, 93% of anal cancers, and 36% of penile cancers in the United States
(US) are attributable to infection with oncogenic HPV types (mainly types 16 and 18).
5
Nononcogenic HPV types (types 6 and 11) cause anogenital warts.
6
Copyright © 2010 American Sexually Transmitted Diseases Association All rights reserved.
Correspondence: Paul L. Reiter, PhD, Department of Health Behavior and Health Education, University of North Carolina Gillings
School of Global Public Health, 323D Rosenau Hall, CB 7440, Chapel Hill, NC 27599-7440. preiter@email.unc.edu..
NIH Public Access
Author Manuscript
Sex Transm Dis. Author manuscript; available in PMC 2014 May 12.
Published in final edited form as:
Sex Transm Dis. 2010 March ; 37(3): 197–203. doi:10.1097/OLQ.0b013e3181bf542c.
NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript

HPV-related disease is of particular concern for gay and bisexual men. The estimated
prevalence of anal HPV infection among gay and bisexual men is about 60% among human
immunodeficiency virus (HIV)-negative individuals and even higher among HIV-positive
individuals, perhaps over 90%.
7-9
Men who have sex with men (MSM) are also at greater
risk for anal cancer compared with the general population,
10-12
with incidence rates
increasing over the last few decades.
13
While a quadrivalent HPV vaccine is currently approved for use in females aged 9 to 26
years in the United States,
14
studies have also shown the vaccine to be efficacious in males.
Early results have shown reductions in persistent HPV infection and genital warts among
vaccinated young men, including MSM.
15-17
Although some men may not derive full
benefit due to previous exposure to HPV types in the vaccine, it may offer them important
protection against HPV vaccine types they have not been exposed to. As with females, HPV
vaccination likely offers the greatest benefit to males if administered before sexual
debut.
18,19
Several countries have licensed HPV vaccine for use in males, though the United
States is not currently one of them.
20
Austria is the only country to currently recommend
HPV vaccination for young males.
20
In the event of approval of prophylactic HPV vaccine for use among males in the United
States, it is important to examine vaccine acceptability and potential correlates such as
knowledge and beliefs. Most studies that have addressed these topics in men have included
no or very few gay and bisexual men.
21-26
The limited research conducted among gay and
bisexual men (primarily using convenience samples recruited at community events or sexual
health centers) found low levels of awareness and knowledge about HPV,
27,28
as well as
moderate interest in receiving the vaccine.
29
In this report, we aimed to characterize correlates of acceptability among a national sample
of gay and bisexual men. We examine modifiable beliefs as potential correlates of HPV
vaccine acceptability among this high-risk population, focusing on constructs from health
behavior theory and previous research on HPV vaccine among adult women, parents, and
adolescent females.
30-32
MATERIALS AND METHODS
Study Design
We interviewed men aged 18 to 59 years who were members of an existing national panel of
US households maintained by Knowledge Networks (Menlo Park, CA) in January 2009,
oversampling men who self-identified as gay or bisexual for our study. Knowledge
Networks identified prospective panel members using list-assisted, random-digit dialing.
Households containing one or more panel members receive free internet access in exchange
for panel members completing multiple internet-based surveys each month. Panel members
in households with existing computer and internet access accumulate points as they
complete surveys, which can then be redeemed for small cash payments at regular intervals.
Of 874 men invited to participate, 609 (70%) completed our cross-sectional, online
survey.
33
We report data collected from men who self-identified as either gay (n = 236) or
bisexual (n = 70), excluding 12 men who indicated that they were not heterosexual but did
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not label their sexual orientation as either gay or bisexual. The Institutional Review Board at
the University of North Carolina approved the study.
Measures
The University of North Carolina Men’s Health Survey is available online at http://
www.unc.edu/~ntbrewer/hpv.htm. We developed survey items based on our previous HPV
vaccine research involving females, parents, and healthcare providers.
31,32,34
We
cognitively tested the survey with 28 gay and bisexual men and further refined it with 8
additional men (including 5 gay and bisexual men) before the study.
The survey measured HPV vaccine acceptability using 5 items assessing how willing a
participant would be to get HPV vaccine if it were approved for use in males (α = 0.97).
Response options were “definitely not willing,” “probably not willing,” “not sure,”
“probably willing,” and “definitely willing.” We classified each participant as either “willing
to get HPV vaccine” (responded probably or definitely willing to 3 or more items) or “not
willing to get HPV vaccine.”
The survey measured HPV awareness by asking participants if they had ever heard of HPV
before the survey. We calculated an HPV knowledge score by summing correct responses to
9 individual items (each correct answer was 1 point) asked only of men who had heard of
HPV (Fig. 1). For analyses, we classified participants as “unaware of HPV” if they had
never heard of HPV, aware of HPV with “low knowledge” if they had heard of HPV but
answered 4 or less knowledge items correctly, or aware of HPV with “high knowledge” if
they had heard of HPV and answered at least 5 knowledge items correctly.
After providing informative statements about HPV and HPV vaccine, the survey assessed
awareness of the vaccine by asking participants if they had ever heard of it before the
survey. The statements informed participants that HPV is a common sexually transmitted
infection (STI), about diseases associated with HPV, and that a vaccine exists to protect girls
and young women against cervical disease. Participants indicated whether they had ever
received any doses of HPV vaccine, attempted to get HPV vaccine but were unsuccessful,
talked to a doctor about getting HPV vaccine for themselves, whether any family members
or friends had received HPV vaccine, and where they would most likely go to get HPV
vaccine (if it were approved for males). The survey also assessed whether participants
thought their healthcare providers would recommend they get the vaccine if it were
approved for males.
The survey used multi-item scales to measure perceived knowledge of HPV-related disease
(3 items, possible range = 1–4, α = 0.74), level of concern about getting HPV-related
disease (3 items, possible range = 1–4, α = 0.53), perceived severity of HPV-related disease
(3 items, possible range = 1–4, α = 0.69), and anticipated regret of not getting HPV vaccine
and later developing genital warts or an HPV infection that could lead to cancer (2 items,
possible range = 1–4, α = 0.88). HPV-related diseases addressed in the perceived
knowledge, concern, and perceived severity scales were genital warts, anal cancer, and oral
cancer. Perceived knowledge response options ranged from “nothing at all” to “quite a lot,”
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while concern, perceived severity, and anticipated regret items had response options ranging
from “not at all” to “quite a lot.”
The survey measured perceived potential barriers to obtaining HPV vaccine with a 4-item
scale (possible range = 1–5, α = 0.65) that addressed adverse effects of HPV vaccination,
cost of HPV vaccine, and difficulty in finding a health care provider with the vaccine
available for males (if approved for use). For each perceived potential barrier, response
options ranged from “not at all” to “extremely.” The survey also assessed perceived
effectiveness of the vaccine against HPV-related disease (4 items, possible range = 1–5, α =
0.94) and perceived likelihood of getting HPV-related disease (4 items, possible range = 1–
5, α = 0.85) using multi-item scales. HPV-related diseases addressed in these scales were
genital warts, anal cancer, oral cancer, and penile cancer. Response options ranged from “no
protection” to “complete protection” for effectiveness items and “no chance” to “certain I
will get (HPV-related disease)” for likelihood items.
Participants provided information on demographic variables and health behaviors (Table 1).
We defined “urban” as living in a metropolitan statistical area and “rural” as living outside
of an metropolitan statistical area.
35
The survey also collected information on reported
history of STIs and cancer (oral, anal, or penile) or lesions (anal or penile).
Data Analysis
We used logistic regression models to examine bivariate correlates of HPV vaccine
acceptability. Statistically significant bivariate predictors (P < 0.05) were entered into a
multivariate logistic regression model. We analyzed unweighted data using SPSS version
16.0 (SPSS Inc., Chicago, IL). All statistical tests were 2-tailed, using a critical α of 0.05.
RESULTS
Participant Characteristics
Most participants were non-Hispanic white (81%), less than 50 years old (60%), reported an
income of at least $60,000 (60%), employed (80%), had health insurance (86%), and lived
in an urban area (93%) (Table 1). A majority of participants were nonsmokers (72%) and
had either not received or were unsure if they had received one or more doses of hepatitis B
vaccine (56%). Most men reported that they had not initiated sex before age 16 (65%) and a
history of 5 or more sexual partners during their lifetime (89%) (median number of reported
lifetime sexual partners = 25). Seventeen percent of men reported a history of HIV infection,
32% reported a history of other STIs, and 2% indicated a history of cancer (oral, anal, or
penile) or lesions (anal or penile).
HPV and HPV Vaccine Awareness and Knowledge
Most men (79%) reported hearing of HPV before the survey, but knowledge levels about
HPV tended to be low among those who had. Men, on average, answered 49% of the 9
knowledge questions correctly (mean = 4.39, median = 4 of 9 items correct). Most
participants knew that HPV is an STI (74%) and that it is a common infection (74%) (Fig.
1). Only 58% thought HPV causes health problems for males, with even fewer knowing
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HPV can cause genital warts (46%) and cancer (anal cancer = 32%, penile cancer = 28%,
oral cancer = 25%). Knowledge items with the highest percentage of incorrect responses
concerned whether HPV causes genital herpes (33%), oral cancer (25%), or penile cancer
(24%). In terms of HPV vaccine, most men (73%) reported hearing of it before the survey.
Beliefs About HPV and HPV Vaccine
Men expressed relatively low levels of perceived knowledge about HPV-related disease
(mean = 1.80, SD = 0.63) and concern about getting HPV-related disease (mean = 1.55, SD
= 0.54), as well as moderate levels of perceived likelihood of getting HPV-related disease
(mean = 2.19, SD = 0.55). Participants generally perceived HPV-related disease to be severe
(mean = 3.32, SD = 0.66). Participants also perceived HPV vaccine to be moderately
effective in protecting against HPV-related disease (mean = 3.03, SD = 0.82), some barriers
to getting HPV vaccine if it were available for males (mean = 2.67, SD = 0.85), and high
levels of anticipated regret if they did not get vaccinated and later got an HPV infection
(mean = 3.39, SD = 0.84). While about one-third of men (34%) thought their doctor would
recommend they get HPV vaccine if it were approved for males, almost half were unsure
(48%).
HPV Vaccine Uptake and Acceptability
No men had received HPV vaccine, 3% reported talking to a doctor previously about getting
the vaccine for themselves, and 8% reported a family member or friend had been vaccinated.
Three men reported trying to get HPV vaccine but were unsuccessful in doing so, indicating
that affordability of the vaccine (n = 2) and the doctor not giving HPV vaccine to males (n =
1) prevented them from getting it. If approved for males, men indicated they would most
likely go to a primary healthcare provider’s office (78%) or gay health center (8%) to get
HPV vaccine.
Approximately 74% (225/306) of men were willing to receive HPV vaccine. Multiple
variables were associated with acceptability of HPV vaccine in bivariate analyses (Tables 1
and 2). Men who either thought or were unsure if their doctor would recommend HPV
vaccine, had received one or more doses of hepatitis B vaccine, or reported 5 or more
lifetime sexual partners were more willing to get HPV vaccine (all P < 0.05). Furthermore,
men willing to get vaccinated reported higher levels of concern about getting HPV-related
disease, perceived severity of HPV-related disease, perceived likelihood of getting HPV-
related disease, perceived effectiveness of HPV vaccine, and anticipated regret if they did
not get vaccinated and later became infected with HPV (all P < 0.05).
In multivariate analysis (Table 3), acceptability was higher among men if they either thought
(OR = 12.87, 95% CI: 4.63–35.79) or were unsure (OR = 3.15, 95% CI: 1.47–6.76) if their
doctor would recommend they get HPV vaccine compared with those who thought their
doctor would not recommend the vaccine, if made available for males. Acceptability was
also higher among those who had 5 or more lifetime sexual partners (OR = 3.39, 95% CI:
1.34–8.55), perceived HPV-related disease to be more severe (OR = 1.92, 95% CI: 1.18–
3.14), perceived HPV vaccine to be more effective (OR = 1.97, 95% CI: 1.27–3.06), or
Reiter et al.
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Frequently asked questions

Q1. What are the contributions in "Acceptability of hpv vaccine among a national sample of gay and bisexual men" ?

Objective—Due to higher rates of human papillomavirus ( HPV ) infection and anal cancer among gay and bisexual men, the authors aimed to characterize their willingness to get HPV vaccine and identify correlates of vaccine acceptability. The authors analyzed data using multivariate logistic regression. In the event of approval of prophylactic HPV vaccine for use among males in the United States, it is important to examine vaccine acceptability and potential correlates such as knowledge and beliefs. In this report, the authors aimed to characterize correlates of acceptability among a national sample of gay and bisexual men. The authors examine modifiable beliefs as potential correlates of HPV vaccine acceptability among this high-risk population, focusing on constructs from health behavior theory and previous research on HPV vaccine among adult women, parents, and adolescent females. The authors interviewed men aged 18 to 59 years who were members of an existing national panel of US households maintained by Knowledge Networks ( Menlo Park, CA ) in January 2009, oversampling men who self-identified as gay or bisexual for their study. The authors report data collected from men who self-identified as either gay ( n = 236 ) or bisexual ( n = 70 ), excluding 12 men who indicated that they were not heterosexual but did Reiter et al. The Institutional Review Board at the University of North Carolina approved the study. These findings identify potentially important beliefs and attitudes for future communication efforts about HPV and HPV vaccine among gay and bisexual men. 1-4 HPV-infected men face potentially severe health consequences, although most infections resolve spontaneously.