Linda M. Niccolai

Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis.

BACKGROUND Human papillomavirus (HPV) vaccination programmes were first implemented in several countries worldwide in 2007. We did a systematic review and meta-analysis to assess the population-level consequences and herd effects after female HPV vaccination programmes, to verify whether or not the high efficacy reported in randomised controlled clinical trials are materialising in real-world situations. METHODS We searched the Medline and Embase databases (between Jan 1, 2007 and Feb 28, 2014) and conference abstracts for time-trend studies that analysed changes, between the pre-vaccination and post-vaccination periods, in the incidence or prevalence of at least one HPV-related endpoint: HPV infection, anogenital warts, and high-grade cervical lesions. We used random-effects models to derive pooled relative risk (RR) estimates. We stratified all analyses by age and sex. We did subgroup analyses by comparing studies according to vaccine type, vaccination coverage, and years since implementation of the vaccination programme. We assessed heterogeneity across studies using I(2) and χ(2) statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure. FINDINGS We identified 20 eligible studies, which were all undertaken in nine high-income countries and represent more than 140 million person-years of follow-up. In countries with female vaccination coverage of at least 50%, HPV type 16 and 18 infections decreased significantly between the pre-vaccination and post-vaccination periods by 68% (RR 0·32, 95% CI 0·19-0·52) and anogenital warts decreased significantly by 61% (0·39, 0·22-0·71) in girls 13-19 years of age. Significant reductions were also recorded in HPV types 31, 33, and 45 in this age group of girls (RR 0·72, 95% CI 0·54-0·96), which suggests cross-protection. Additionally, significant reductions in anogenital warts were also reported in boys younger than 20 years of age (0·66 [95% CI 0·47-0·91]) and in women 20-39 years of age (0·68 [95% CI 0·51-0·89]), which suggests herd effects. In countries with female vaccination coverage lower than 50%, significant reductions in HPV types 16 and 18 infection (RR 0·50, 95% CI 0·34-0·74]) and in anogenital warts (0·86 [95% CI 0·79-0·94]) occurred in girls younger than 20 years of age, with no indication of cross-protection or herd effects. INTERPRETATION Our results are promising for the long-term population-level effects of HPV vaccination programmes. However, continued monitoring is essential to identify any signals of potential waning efficacy or type-replacement. FUNDING The Canadian Institutes of Health Research.

Misperceived risk among female adolescents: Social and psychological factors associated with sexual risk accuracy

This study of 411 urban female adolescents had 3 objectives: (a) assess the relationship between perceived risk and sexual risk behavior (condom use, number of partners, partner risk, presence of STDs, and aggregate sexual risk), (b) assess the accuracy of risk perceptions, and (c) identify variables related to inaccurate sexual risk perceptions. Participants were classified as accurate or inaccurate risk perceivers on the basis of actual sexual behavior and perceived risk. Accurate versus inaccurate risk perceivers were compared on psychological maintenance variables (self-esteem, distress, and coping), relationship context variables (partnership duration and pressure to have unprotected sex), and risk knowledge at different levels of sexual risk. Approximately half of the participants underestimated the risk of their sexual behavior. Accurate and inaccurate risk perceivers differed on risk knowledge, partnership duration, and pressure to have unprotected sex.

Racial/Ethnic and Poverty Disparities in Human Papillomavirus Vaccination Completion

BACKGROUND Two vaccines against human papillomavirus (HPV), a necessary cause of cervical cancer, are currently licensed and recommended for routine administration in the U.S. to girls in a three-dose series. PURPOSE This study examined effects of race/ethnicity, poverty, and year on completion of the three-dose HPV vaccine series among those who initiated vaccination. METHODS Data from the 2008-2009 National Immunization Survey-Teen for girls aged 13-17 years who received at least one dose of HPV vaccine (n=7606) were analyzed in 2010-2011 using logistic regression to adjust for covariates including measures of access to care. RESULTS During this 2-year period, 55% of adolescent girls who initiated vaccination completed the three-dose series. Completion was significantly higher in 2009 (60%) compared to 2008 (48%; p<0.001). After controlling for covariates, adolescents who were black (AOR=0.48, 95% CI=0.40, 0.57) or Hispanic (AOR=0.75, 95% CI=0.64, 0.88) were significantly less likely to complete vaccination than whites. Adolescents living below the federal poverty level were significantly less likely to complete vaccination than adolescents with household incomes >

Adolescent women underestimate their susceptibility to sexually transmitted infections

75,000 (AOR=0.76, 95% CI=0.63, 0.92). There was no significant interaction between race/ethnicity and year (p=0.92). Although poverty was associated with lower completion rates in 2008, this association was not observed in 2009 (p<0.05 for poverty-year interaction). CONCLUSIONS HPV vaccination completion rates increased between 2008 and 2009. However, significant differences by race/ethnicity and poverty were observed, and the racial/ethnic differences persisted.

Associations of sex ratios and male incarceration rates with multiple opposite-sex partners: potential social determinants of HIV/STI transmission.

Objectives: Adolescent females are at significant risk for sexually transmitted infections (STI) and may not accurately incorporate indicators of risk into their perceptions of susceptibility. The objectives of the current analyses were to: (1) examine the relation between perceived susceptibility and indicators of risk; and (2) investigate the relation between perceived susceptibility and actual STI diagnosis. Methods: Participants were 209 sexually active adolescent females. Indicators of STI risk included STI history, recent symptoms, and sexual risk behaviour (that is, recent unprotected sex and numbers of sexual partners). Chlamydia and gonorrhoea infection were assessed at baseline, 6, and 12 months post-baseline using urine based ligase chain reaction testing. Results: Most participants perceived little or no chance that they would be diagnosed with an STI in the following year. There was no relation between almost all STI indicators and perceptions of susceptibility. Among those receiving a positive chlamydia or gonorrhoea test (n=49) at baseline or in the year following, almost all (81.3%) had perceived themselves to be at little or no risk. Conclusion: The adolescent females in this sample did not accurately perceive their susceptibility to STI. They must be enabled to more effectively assess and modify their risk.

High postpartum rates of sexually transmitted infections among teens: pregnancy as a window of opportunity for prevention

Objectives. Racial/ethnic disparities in heterosexual transmission of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs) have been hypothesized to be related to the high rate of incarceration and the shortage of men in black communities. This study tested associations of having multiple sex partners with these factors. Methods. Racial/ethnic-specific Census data on the sex ratio and the male incarceration rate were categorized into tertiles and matched with individual data from the National Health and Nutrition Examination Survey 1999–2004 by county of residence for non-Hispanic black, non-Hispanic white, and Mexican American participants. We used logistic regression analyses to examine whether these factors were associated with having multiple opposite-sex partners in the past year. Results. Sex ratios and incarceration rates varied greatly by race/ethnicity; however, we observed significant associations within each racial/ethnic group. Non-Hispanic black men in counties with a greater shortage of males (adjusted odds ratio [AOR] = 1.9; 95% confidence interval [CI] 1.1, 3.5) and a greater number of incarcerated males (AOR=1.6; 95% CI 1.1, 2.3) in the non-Hispanic black population had significantly greater odds of having two or more partners. Those in two low sex-ratio categories (AOR=2.4; 95% CI 1.0, 5.8 and AOR=4.1; 95% CI 1.6, 10.0) and one high incarceration-rate category (AOR=2.1; 95% CI 1.2, 3.6) had significantly greater odds of having five or more partners. Conclusion. Sex ratios and incarceration rates were associated with the number of opposite-sex partners in some groups. Because the risk of HIV/STI transmission depends, in part, on the number of partners, it is important to determine the causal relationships among these associations to help better understand racial/ethnic HIV/STI disparities and improve prevention programs and interventions.

Short and long-term impact of adolescent pregnancy on postpartum contraceptive use: implications for prevention of repeat pregnancy.

Objectives: To identify incidence and predictors of Chlamydia trachomatis and Neisseria gonorrhoeae among postpartum adolescents. These estimates are compared to similar estimates among a cohort of non-pregnant, sexually active teens. Methods: 203 pregnant and 208 non-pregnant adolescents aged 14–19 years were recruited from 10 community based health clinics in Connecticut, United States. Structured interviews and sexually transmitted infection (STI) testing using ligase chain reaction (LCR) were conducted at a baseline visit (during the third trimester for the pregnant adolescents), and at 6 and 12 month follow up visits (3 and 9 months post partum, for those pregnant at baseline). Results: Among pregnant teens, new infections of C trachomatis and N gonorrhoeae increased from 7.1% at the 6 month follow up interview to 14.3% at the 12 month follow up interview; among non-pregnant teens, new infections remained relatively stable over the 6 and 12 month follow up interviews (9.0% to 8.3%) (group by time interaction, p = 0.005). C trachomatis and N gonorrhoeae prevalence was 1.9 times higher (95% CI: 0.97 to 3.89, p = 0.06) among teens in the late postpartum follow up compared to the non-pregnant teens, controlling for baseline STIs. Predictors of postpartum STIs included having a new partner and number of partners per year of sexual activity. Conclusions: Postpartum adolescents are vulnerable to STIs. Routine prenatal and postpartum care provide unique opportunities to promote condom use and other risk reduction interventions among adolescents. If sustained post partum, long term reproductive health can be promoted.

Disclosure of HIV status to sexual partners: predictors and temporal patterns.

PURPOSE To describe patterns and changes in contraceptive use among pregnant adolescents in early and later postpartum compared with nonpregnant adolescents. METHODS One-hundred-seventy-six pregnant and 187 nonpregnant adolescents, recruited through community clinics, were interviewed three times (baseline, 6-month follow-up, 12-month follow-up) about their condom and hormonal contraceptive practices. Changes in contraception use and patterns of consistent hormonal and/or condom use were examined. Statistical analyses included General Estimating Equations (GEE) and multinomial regression. RESULTS Pregnant adolescents increased hormonal contraceptive use from baseline to early postpartum, but decreased use from early postpartum to late postpartum. Nonpregnant adolescents did not change their hormonal contraceptive use over time. Neither group changed condom use over time. Pregnant adolescents were more likely to be consistent dual users and hormonal-only users during the 6-month follow-up compared with nonpregnant adolescents. These findings persisted at the 12-month follow-up, although there was a decline in hormonal contraception use. CONCLUSIONS Adolescents change their contraceptive use during the postpartum period. Given the slight decline in contraceptive use in late postpartum in this sample, more work is necessary to maintain motivation to continue these positive postpartum trends.

Incidence and predictors of reinfection with Trichomonas vaginalis in HIV-infected women.

BACKGROUND AND OBJECTIVES Failure to disclose human immunodeficiency virus (HIV) infection to sexual partners interferes with risk reduction. GOAL OF THIS STUDY The purpose of this study was to identify factors associated with disclosure and failure to disclose HIV infection to sexual partners and to describe condom use with nondisclosure. STUDY DESIGN A longitudinal survey study of HIV seropositive persons recruited at a public STD clinic. RESULTS Approximately 76% of the study population (n = 147) reported disclosing their HIV status to their last sex partner at baseline. Predictors of disclosure included consistent condom use and being in a monogamous relationship. Twenty-two percent of those who disclosed at baseline reported nondisclosure during follow-up. Approximately 23% reported not using a condom with a person to whom their status was not disclosed. CONCLUSIONS These results suggest that ongoing partner notification may be necessary to increase disclosure of HIV status to sex partners over time.

Unprotected intercourse for extra money among commercial sex workers in Kinshasa, Democratic Republic of Congo.

Background and Objectives: The presence of sexually transmitted infections (STIs) may facilitate transmission of HIV to uninfected partners. Goal: To describe the incidence of reinfection with Trichomonas vaginalis in HIV‐infected women and to assess predictors of reinfection. Study Design: A retrospective cohort study using data abstracted from medical records of HIV‐infected women with at least one diagnosis of trichomoniasis. Results: Approximately one third (36%) of the study population was reinfected with T vaginalis during the follow‐up period, with an incidence of 16.4 reinfections per 100 person years. Significant predictors of reinfection included history of another STI (hazard ratio, 1.52; 95% CI, 1.08‐2.14) and becoming pregnant during the follow‐up period (hazard ratio, 0.59; 95% CI, 0.39‐0.87). Conclusions: There is a high rate of reinfection with T vaginalis in HIV‐infected women. Further research that includes information on sexual partners should be conducted to better describe the reinfection patterns of trichomoniasis.