Catch-up Program Research Articles

Too Much of a Good Thing? When to Stop Catch-Up Vaccination

During the 20th century, deaths from a range of serious infectious diseases decreased dramatically due to the development of safe and effective vaccines. However, infant immunization coverage has increased only marginally since the 1960s, and many people remain susceptible to vaccine-preventable diseases. "Catch-up vaccination" for age groups beyond infancy can be an attractive and effective means of immunizing people who were missed earlier. However, as newborn vaccination rates increase, catch-up vaccination becomes less attractive: the number of susceptible people decreases, so the cost to find and vaccinate each unvaccinated person may increase; in addition, the number of infected individuals decreases, so each unvaccinated person faces a lower risk of infection. This article presents a general framework for determining the optimal time to discontinue a catch-up vaccination program. We use a cost-effectiveness framework: we consider the cost per quality-adjusted life year gained of catch-up vaccination efforts as a function of newborn immunization rates over time and consequent disease prevalence and incidence. We illustrate our results with the example of hepatitis B catch-up vaccination in China. We contrast results from a dynamic modeling approach with an approach that ignores the impact of vaccination on future disease incidence. The latter approach is likely to be simpler for decision makers to understand and implement because of lower data requirements.

O17.3 Do We Need to Vaccinate Males Against HPV?

BackgroundFrom mid-2007 Australia funded a universal HPV vaccination programme for young females, which achieved high coverage rates. In 2013, Australia has become the first country to extend the HPV vaccination...

Factors Associated With Receipt of Two Doses of Varicella Vaccine Among Adolescents in the United States

In 2006, routine two-dose varicella vaccination for all children was recommended, including a second dose catch-up program for older children and adolescents. Recent studies have shown that a second dose of the vaccine provides incremental protection against varicella disease. This study is a cross-sectional analysis of data collected in the National Immunization Survey-Teen 2010 combined with publicly available data related to state immunization requirements. Bivariate and multivariable logistic regression analyses were performed to examine individual-level and state-level factors associated with receipt of two doses of varicella vaccine among 10,542 adolescents 13 to 17 years of age with no history of varicella. Overall, 58.1% of adolescents without any history of varicella had received two doses of varicella vaccine. Coverage varied widely among states, ranging from 19.7% in South Dakota to 85.3% in Rhode Island. In the multivariable model, receipt of two doses of varicella vaccine was significantly associated with younger age, higher maternal education level, private health insurance, more frequent health care visits, receipt of both quadrivalent meningococcal conjugate and tetanus, diphtheria, and acellular pertussis vaccinations, and residing in a state with two-dose policies for middle school entry. Vaccines for Children program-eligible adolescents were less likely to have received two doses. Two-dose varicella vaccination coverage remained low among adolescents in 2010, despite the universal recommendation. Programs that are aimed specifically at Vaccines for Children program-eligible adolescents, state policies requiring two doses for middle school entry, and broad education and implementation of the adolescent vaccination platform may help to improve varicella vaccination coverage.

The Cost-Effectiveness Analysis of a Quadrivalent Human Papillomavirus Vaccine (6/11/16/18) for Females in Japan

ObjectiveWe assessed the epidemiological and economic impact of a quadrivalent human papillomavirus (HPV) (6/11/16/18) vaccine for females in preventing cervical cancer, cervical intraepithelial neoplasia grades 2 and 3 (CIN 2/3), cervical intraepithelial neoplasia grade 1 (CIN 1), and genital warts in Japan by using a transmission dynamic model. MethodsA published mathematical model of the transmission dynamics of HPV infection and disease was adapted for Japan. Model inputs were used from Japan or the Asia/Pacific region when available; otherwise, the default values in the original model were used. The transmission dynamic model was used to assess the epidemiological and economic impact of a quadrivalent HPV (6/11/16/18) vaccine for females in preventing cervical cancer, CIN 2/3, CIN 1, and genital warts in Japan.Maintaining current cervical cancer screening practices, we evaluated two strategies: routine vaccination of females by age 12 years (S1), and S1 combined with a temporary (5 years) female catch-up program for age 12 to 24 years (S2). The vaccine coverage rate was 80% for the routine and 50% for the catch-up vaccination programs. ResultsCompared with no vaccination, both vaccination strategies significantly reduced the incidence of HPV 6/11/16/18–related disease. The most effective strategy was S2. By using this strategy over 100 years in the Japanese population, the estimated cumulative percentage reduction in incident HPV 6/11/16/18–related genital warts-female, genital warts-male, cervical CIN 1, CIN 2/3, and cervical cancer cases was 90% (2,113,723 cases), 86% (2,082,637 cases), 72% (263,406 cases), 71% (1,328,366 cases), and 58% (323,145 cases), respectively. The cost-effectiveness ratios were JPY 1,244,000, and JPY 1,205,800 per quality-adjusted life-year gained for S1 and S2 compared with no vaccination, respectively, over a time horizon of 100 years. ConclusionWe conclude that a quadrivalent HPV vaccination program for females can reduce the incidence of cervical cancer, CIN, and genital warts in Japan at a cost-per-quality-adjusted life-year ratio within the range defined as cost-effective.

Gaps in detailed knowledge of human papillomavirus (HPV) and the HPV vaccine among medical students in Scotland

BackgroundA vaccination programme targeted against human papillomavirus (HPV) types16 and 18 was introduced in the UK in 2008, with the aim of decreasing incidence of cervical disease. Vaccine roll out to 12–13 year old girls with a catch-up programme for girls aged up to 17 years and 364 days was accompanied by a very comprehensive public health information (PHI) campaign which described the role of HPV in the development of cervical cancer.MethodsA brief questionnaire, designed to assess acquisition of knowledge of HPV infection and its association to cervical cancer, was administered to two different cohorts of male and female 1st year medical students (school leavers: 83% in age range 17–20) at a UK university. The study was timed so that the first survey in 2008 immediately followed a summer's intensive PHI campaign and very shortly after vaccine roll-out (150 students). The second survey was exactly one year later over which time there was a sustained PHI campaign (213 students).ResultsWe addressed three research questions: knowledge about three specific details of HPV infection that could be acquired from PHI, whether length of the PHI campaign and/or vaccination of females had any bearing on HPV knowledge, and knowledge differences between men and women regarding HPV. No female student in the 2008 cohort had completed the three-dose vaccine schedule compared to 58.4% of female students in 2009. Overall, participants’ knowledge regarding the sexually transmitted nature of HPV and its association with cervical cancer was high in both year groups. However, in both years, less than 50% of students correctly identified that HPV causes over 90% of cases of cervical cancer. Males gave fewer correct answers for these two details in 2009. In 2008 only around 50% of students recognised that the current vaccine protects against a limited subset of cervical cancer-causing HPV sub-types, although there was a significant increase in correct response among female students in the 2009 cohort compared to the 2008 cohort.ConclusionsThis study highlights a lack of understanding regarding the extent of protection against cervical cancer conferred by the HPV vaccine, even among an educated population in the UK who could have a vested interest in acquiring such knowledge. The intensive PHI campaign accompanying the first year of HPV vaccination seemed to have little effect on knowledge over time. This is one of the first studies to assess detailed knowledge of HPV in both males and females. There is scope for continued improvements to PHI regarding the link between HPV infection and cervical cancer.

Kinetics of measles antibody by hemagglutination inhibition assay in children in south-west and north-central Nigeria

We investigated the antibody level of children against wild measles virus in view of recurrent measles epidemics, in order to provide information on immunization status for health policies and for the global measles mortality reduction initiative. Two hundred and seventy-three children between the ages of 10 months and 13 years were recruited for this study from three hospital facilities in south-west and north-central Nigeria. Serum samples were collected from February to July 2009, and laboratory examination commenced in August of the same year. Measles hemagglutinin (HA) antigen was prepared by culturing the measles vaccine virus strain (Edmonston-Zagreb) in a vero/hSLAM cell line. Serum samples were treated to get rid of potentiating factors, non-specific inhibitors, and agglutinins before the HA/hemagglutination inhibition (HI) procedure. Out of the 175 children vaccinated in Ibadan, 60 (34.3%) had an antibody level not sufficient to protect against measles infection. Likewise, 12 (25.0%) vaccinated children from Ilorin had an antibody level not sufficient to protect against measles infection. There was no significant difference in the level of protection between the children in Ibadan and Ilorin (p>0.05). The geometric mean titer (GMT) was 53.83 for males and 48.64 for females. There was no significant difference between the GMTs of females and males in both locations (p>0.05). Also, no significant difference was observed in the GMTs of children in both locations (p>0.05). Of the vaccinated children, 157 (57.5%) developed protective measles virus HI antibody, which is not enough to maintain protective herd immunity. Hence there is a need for catch-up and follow-up vaccination programs, especially in rural areas and places with difficult terrains, in order to reduce measles mortality.

Promoting cervical screening after introduction of the human papillomavirus vaccine: the effect of repeated mass media campaigns

In 2007, Australia implemented an ongoing, school-based human papillomavirus (HPV) vaccination programme for school-aged girls, and a catch-up programme for 18-26-year-old women that ran until the end of 2009. The availability of what is widely known as the 'cervical cancer vaccine' means there is the potential for women to believe, incorrectly, that they no longer require regular cervical screening, and this risk needs to be addressed. The current study aimed to assess the effect of three mass media campaigns to promote cervical screening on the rate of cervical screening tests in the Australian state of Victoria, after HPV vaccine became available. Seasonal time series assessed the effect of media campaigns broadcast in 2007, 2009 and 2010 on the rate of weekly cervical screening tests in Victorian women from 2006 to 2010, stratified by time since last screening test. The 2007 and 2009 media campaigns significantly increased the number of cervical screening tests per week. The 2007 campaign had a significant impact on lapsed screeners (>36 months since last test), overdue screeners (28-36 months since last test), and women never previously screened. The 2009 campaign significantly increased screening tests for overdue screeners, and the 2010 media campaign was associated with a significant increase in screening tests for lapsed screeners. A well-researched and carefully pretested television advertising campaign with accurate, actionable messages can elicit appropriate screening behaviour among some of the appropriate groups even in a changed environment of complex, and potentially competing, messages.

Evaluation of Australia's varicella vaccination program for children and adolescents

ObjectiveThis paper examines how the monovalent varicella vaccine for children, with an adolescent catch-up dose, was introduced into Australia's National Immunisation Program (NIP), focusing on programme implementation. MethodsSemi-structured interviews were conducted with key informants involved in programme implementation. Key themes from interviews were identified through content analysis. Childhood coverage was assessed using data from the Australian Childhood Immunisation Register (ACIR) with adolescent coverage obtained from state/territory immunisation programmes. Seroprevalence data were analysed from national serosurveys conducted before and after programme commencement. ResultsImplementation challenges for both parents and providers included: (a) parental report of previous infection as an exclusion criterion; (b) introducing a vaccine on its own at 18 months of age; and (c) adding the adolescent dose into existing school-based vaccination programmes with parental reported exclusion criteria. Despite these challenges, coverage rapidly reached 83% by 24 months of age and 30–33% for the adolescent catch-up dose. When considered in conjunction with estimated pre-vaccination natural immunity in both target groups (20% and 83%, respectively) coverage can be considered high. The serosurvey under-estimated coverage in 2-year-old children but was useful to assess trends in population immunity. ConclusionThe introduction of a single dose of monovalent varicella vaccine at 18 months of age and a school-based catch-up programme at 11–13 years of age successfully achieved high coverage, notwithstanding some challenges. Reported natural infection has been an exclusion criterion for vaccination, but as the programme matures and circulation of wild-type virus decreases, the need for this warrants consideration. There is a need for sensitive laboratory assays to measure vaccine-induced immunity at a population level.

Yetistirici Sinif Ögretim Programinin (YSÖP) Degerlendirilmesi

The purpose of this study is to evaluate the integration status of students who have been attending classes with same age peers after catchup education program in a primary school opened in Gaziantep according to views of stakeholders who are their teachers, classmates and themselves. By the way, the effectiveness of catch-up education program is evaluated. The data was gathered via participatory observation and interviews. The data gathered from interviews with stakeholders were analyzed with technique of content analysis in qualitative method. The answers to open-ended questions were analyzed separately for the stakeholders. Then, by combining the results of the analysis, the stakeholders' opinions about integration of the students were determined. The interviews and participant observation indicated that the students have integration problems with their school, teacher, classroom and their classmates in their new peer aged classrooms after the catch-up education program. The main purpose of the catch-up education program is to adapt the students with their school, teachers, classroom and classmates but the study results show that the catchup education program did not fully serve its purpose. Many activities have been done is to ensure students’ adaptation to their school during catch-up education program but after this program, no adaptation activities have been done in their new peer aged classrooms.

Designing for Diversity: A Case Study Exploring Implications of Ecological Psychology for Inclusion

The dominant psychological paradigm which underpins institutionalised learning has perpetuated a deficit rationality whereby children outside of normative developmental ranges are understood to be needy of catch-up or compensatory programs. This perennial approach magnifies and perpetuates difference, seemingly rendering the concept of inclusion in school contexts fallacious. This case study will exemplify an alternative way for schools to nurture and implicitly include young people and their families in a community of practice (Lave & Wenger, 1991). The Studio Learning Project (SLP) was established to create an additional space for learning which allows children the freedom to engage in self-instigated or negotiated projects. Reconceptualising learning from an ecological perspective, as a transaction between actors and their environments, the study supports giving increased consideration to learning as an individual-environment transaction (Barab & Roth, 2006). This places the management of resources and design of learning spaces at the forefront of decision-making for schools and their communities concerned with inclusive education. Kalantzis and Cope (2008) have claimed that designing for learning is the new work of teaching. Ecological psychology describes effectivities and affordance networks (Barab & Roth, 2006; Barab & Plucker, 2002) which transcend the individualistic focus of the dominant theoretical paradigm affecting schools, and suggest the environment and its physical, temporal, and social resources are cause for exploration when it comes to inclusive education.

Human papillomavirus vaccination in Auckland: Reducing ethnic and socioeconomic inequities

BackgroundThe New Zealand HPV publicly funded immunisation programme commenced in September 2008. Delivery through a school based programme was anticipated to result in higher coverage rates and reduced inequalities compared to vaccination delivered through other settings. The programme provided for on-going vaccination of girls in year 8 with an initial catch-up programme through general practices for young women born after 1 January 1990 until the end of 2010. ObjectiveTo assess the uptake of the funded HPV vaccine through school based vaccination programmes in secondary schools and general practices in 2009, and the factors associated with coverage by database matching. MethodsRetrospective quantitative analysis of secondary anonymised data School-Based Vaccination Service and National Immunisation Register databases of female students from secondary schools in Auckland District Health Board catchment area. Data included student and school demographic and other variables. Binary logistic regression was used to estimate odds ratios and significance for univariables. Multivariable logistic regression estimated strength of association between individual factors and initiation and completion, adjusted for all other factors. ResultsThe programme achieved overall coverage of 71.5%, with Pacific girls highest at 88% and Maori at 78%. Girls higher socioeconomic status were more likely be vaccinated in general practice. ConclusionSchool-based vaccination service targeted at ethic sub-populations provided equity for the Maori and Pacific student who achieved high levels of vaccination.

Rubella seroprevalence in the first birth cohort reaching fertility age after 20 years of two dose universal vaccination policy in Israel

BackgroundA national program of a 2-dose universal childhood MMR vaccination policy has been in effect in Israel since 1988. As the 1988 birth cohort reached fertility age, questions regarding immunity against rubella were raised. ObjectiveTo assess the seroprevalence of rubella IgG antibodies among young Israeli adults born after 1987 in comparison to previous birth cohorts, in order to determine evidence based policy for prevention of rubella and congenital rubella syndrome. MethodsWe conducted a seroprevalence study of rubella IgG antibodies among 416 Israeli adults (42.5% females) born in 1988–1989, based on a representative sample of sera collected at age 18–19 upon recruitment to mandatory military service in 2007. ResultsIn total, 87.7% were seropositive (>15IU/ml) as compared with 84.8% in the 1999 recruitment (P=0.26) and 93.4% in 1987 (P=0.004). Yet there was a difference by gender. The proportion of seropositives among female young adults (92.7%) was significantly lower as compared to those measured in the 1999 (99.2%, P=0.001) and 1987 (99.0%, P=0.006) recruitments. The proportion of seropositives among males (84.1%) was significantly higher as compared to those measured in 1999 (73.0%, P<0.001) but similar to those of 1987 (88.8%, P=0.13). Females born in the FSU were found to be high risk groups as 11.5% were seronegative. ConclusionsOur findings indicate that despite a successful program of congenital rubella syndrome prevention in Israel, there is a decline in seroprevalence among female young adults, especially immigrants from the FSU. A proactive catch-up program for females, especially for those of higher risk for susceptibility should be considered in Israel and in other countries.

The end of the Australia antigen? An ecological study of the impact of universal newborn hepatitis B vaccination two decades on

BackgroundA universal newborn hepatitis B (HBV) vaccination program was introduced in the Northern Territory of Australia in 1990, followed by a school-based catch-up program. We evaluated the prevalence of hepatitis B infection in birthing women up to 20 years after vaccination and compared this to women born before the programs commenced. MethodsA cohort of birthing mothers was defined from Northern Territory public hospital birth records between 2005 and 2010 and linked to laboratory confirmed notifications of chronic HBV, based principally on a record of hepatitis B surface antigen detection. Prevalence of HBV was compared between women born before or after implementation of the newborn and catch-up vaccination programs. FindingsAmong 10797 birthing mothers, 138 (1.3%) linked to a chronic HBV record. HBV prevalence was substantially higher in Aboriginal women compared to non-Indigenous women (2.4% versus 0.04%; p<0.001). Among 5678 Aboriginal women, those eligible for catch-up and newborn HBV vaccination programs had a significantly lower HBV prevalence than older women born prior to the programs: HBV prevalence respectively 2.2% versus 3.5%, (OR 0.61, 95%CI 0.43–0.88) and 0.8% versus 3.5% (OR 0.21, 95%CI 0.11–0.43). This represents a risk reduction of respectively 40% and 80% compared to unvaccinated women. InterpretationThe progressively greater reduction in the prevalence of chronic HBV in adult Aboriginal women co-inciding with eligibility for catch-up and newborn vaccination programs is consistent with a significant impact from both programs. The use of data derived from antenatal screening to track ongoing vaccine impact is applicable to a range of settings globally.

Vaccins anti-méningococciques: des politiques vaccinales et des recommandations hétérogènes

In European Country, Canada, Australia and Brazil immunization program with conjugate meningococcal C, including universal vaccination of infants or toddlers, with a catch-up program up to 19 y in several areas, have been successful in reducing disease incidence through direct and indirect protection. In USA, quadrivalent conjugate vaccines targeting serogroups ACYW135 are used in programs of adolescent immunization at 10 and 15 years because serotype Y is frequent. A mass immunization campaign against serogroupe A disease with a conjugate vaccine is beginning in African belt of meningitis. Polysaccharide vaccines A, C or ACYW135 are used in travelers but quadrivalent conjugate vaccine, with larger targets, gives higher titers after booster and must be preferred. Some questions are pending: immunize before or after one year of age, a booster dose in adolescence and the routine use of quadrivalent conjugate vaccine in Europe if the incidence of serotype Y is growing.

Human papillomavirus infection: knowledge, attitudes, and behaviors among lesbian, gay men, and bisexual in Italy.

BackgroundThis cross-sectional study assess knowledge, attitudes, and behavior towards the human papillomavirus (HPV) and the vaccination among a random sample of 1000 lesbian, gay men, and bisexual women and men.MethodsA face-to-face interview sought information about: socio-demographic characteristics, knowledge about HPV infection, perception of risk towards HPV infection and/or cervical, anal, and oropharyngeal cancers, perception of the benefits of a vaccination to prevent cervical, anal, and oropharyngeal cancers, sexual behaviors, health-promoting behaviors, and willingness to receive the HPV vaccine.ResultsOnly 60.6% had heard about the HPV infection and this knowledge was significantly higher in female, in those being a member of a homosexual association, in those having had the first sexual experience at a younger age, in those having received information about the HPV infection from physicians, and in those having no need of information about HPV infection. A higher perceived risk of contracting HPV infection has been observed in those younger, lesbian and gay men, who have heard of HPV infection and knew the risk factors and its related diseases, who have received information about HPV infection from physicians, and who need information about HPV infection. Only 1.7% have undergone HPV immunization and 73.3% professed intent to obtain it in the future. The significant predictors of the willingness to receive this vaccine were belief that the vaccination is useful, perception to be at higher risk of contracting HPV infection, and perception to be at higher risk of developing cervical, anal, and oropharyngeal cancers.ConclusionsInformation and interventions are strongly needed in order to overcome the lack of knowledge about HPV infection and its vaccination. Inclusion of boys in the national vaccination program and initiate a catch-up program for men who have sex with men up to 26 years may reduce their burden of HPV-related disease.

Modeling the impact of the 13-valent pneumococcal conjugate vaccine serotype catch-up program using United States claims data

BackgroundAnalysis of US claims data from April 2010 to June 2011 estimated that 39% of the 13-valent pneumococcal conjugate vaccine (PCV13) catch-up eligible cohort would ever receive the catch-up vaccination; a previous analysis assumed 87%.MethodsThis updated figure was applied to a previously published 10-year Markov model while holding all other inputs constant.ResultsOur model estimated that the catch-up program as currently implemented is estimated to prevent an additional 1.7 million cases of disease in children aged ≤59 months over a 10-year period, compared with routine PCV13 vaccination with no catch-up program.ConclusionsBecause 39% catch-up uptake is less than the level of completion of the 4-dose primary PCV13 series, vaccine-preventable cases of pneumococcal disease and related deaths could be decreased further with additional uptake of catch-up vaccination in the catch-up eligible cohort.

Comparatively low attendance during Human Papillomavirus catch-up vaccination among teenage girls in the Netherlands: Insights from a behavioral survey among parents

BackgroundThe Dutch Human Papillomavirus (HPV) catch-up vaccination program in 2009 appeared less successful than expected. We aimed to identify the most important determinants of refusing the vaccination.MethodsTwo thousand parents of girls born in 1996 targeted for HPV vaccination received an invitation letter to participate in a questionnaire study. Two study groups were defined: the first group consisted of parents of girls who had accepted the vaccine and already received the first dose of HPV vaccination. The second group consisted of parents whose daughters were not vaccinated. The questionnaire consisted of a broad spectrum of possible determinants that were revealed after literature search and discussions with the stakeholders.ResultsFour hundred sixty nine questionnaires (24%) were returned, 307 (31%) from those who accepted and 162 (16%) from those who declined the vaccine. The decision not to accept the vaccine was largely determined by: (i) perception that the information provided by the government about the vaccine was limited or biased (OR 13.27); (ii) limited trust, that the government would stop the vaccination program if there were serious side effects (OR 9.95); (iii) lack of knowledge about the effectiveness of the vaccine (OR 7.67); (iv) concerns about the side effects of the vaccine (OR 4.94); (v) lack of conviction that HPV can be extremely harmful (OR 3.78); (vi) perception that the government is strongly influenced by vaccine producers (OR 3.54); and (vii) religious convictions (OR 2.18).ConclusionsThis study revealed several determinants for HPV vaccination uptake after implementation of the HPV vaccine for adolescent girls. These determinants should be taken into consideration in order to successfully implement HPV vaccination into National Immunization Programs.

Feasibility of a Catch-up HPV Vaccination Program Among College Students Attending a Large Rural University in the South

Our study explored the eligibility and willingness of students to participate in a university-wide catch-up Human papillomavirus (HPV) vaccination program. A total of 1804 electronic surveys (82% response) assessing demographics, HPV knowledge, eligibility, and willingness were gathered. HPV knowledge was moderate, with just over a quarter (26%) answering all knowledge items correctly. Most understood that HPV is sexually transmitted (82%) while fewer knew HPV can cause cancer in men (40%) and that a vaccine is available for men (32%). Eligibility (71%) and willingness (71%) to receive school-based HPV vaccinations was high. These data support developing a college-wide catch-up HPV vaccination program.

Correlates of Susceptibility to Hepatitis B among People Who Inject Drugs in Sydney, Australia

Despite a safe, effective vaccine, hepatitis B virus (HBV) vaccination coverage remains low among people who inject drugs (PWID). Characteristics of participants screened for a trial investigating the efficacy of financial incentives in increasing vaccination completion among PWID were examined to inform targeting of vaccination programs. Recruitment occurred at two health services in inner-city Sydney that target PWID. HBV status was confirmed via serological testing, and questionnaires elicited demographic, drug use, and HBV risk data. Multinomial logistic regression was utilized to determine variables independently associated with HBV status. Of 172 participants, 64% were susceptible, 17% exposed (HBV core antibody-positive), and 19% demonstrated evidence of prior vaccination (HBV surface antibody ≥ 10 mIU/ml). Compared with exposed participants, susceptible participants were significantly more likely to be aged less than 35 years and significantly less likely to be receiving current opioid substitution therapy (OST) and to test hepatitis C antibody-positive. In comparison to vaccinated participants, susceptible participants were significantly more likely to be male and significantly less likely to report daily or more frequent injecting, current OST, and prior awareness of HBV vaccine. HBV vaccination uptake could potentially be increased by targeting younger, less frequent injectors, particularly young men. In addition to expanding vaccination through OST, targeting "at risk" youth who are likely to have missed adolescent catch-up programs may be an important strategy to increase coverage. The lack of an association between incarceration and vaccination also suggests increasing vaccination uptake and completion in adult and juvenile correctional facilities may also be important.

XVIII Latin American Congress

XVIII Latin American Congress