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Acceptability of human papillomavirus (HPV) vaccination seems to be high in the Western world but fewer data are available for men than for women. There are also concerns that HPV vaccination might lead young people to change their healthcare-related behaviours. We investigated these issues in a population-based survey performed in Sweden during January-May, 2007, just after HPV vaccination had been licensed. A total of 10567 men and women aged 18 to 30 years participated. The intention to accept HPV vaccination among these young adults was relatively high but could likely be improved with higher awareness of HPV-related diseases as well as of the safety and efficacy of vaccines in general. Also, the cost of the vaccine needs to be affordable. Even though few young adults stated their healthcare-related behaviours would change after HPV vaccination, a significant number were uncertain, suggesting a need for continued educational efforts when HPV-vaccinating this group.

In this population-based survey undertaken in Sweden in 2007, we investigated correlates of attitudes to human papillomavirus (HPV) vaccination among parents of children aged 12-15 years. We invited 16,000 parents of girls and 4,000 parents of boys, randomly selected from the Swedish population. Response rates were 70 and 69%, respectively. Multinomial logistic regression models were applied to investigate correlates of acceptability to HPV vaccination. Among studied parents, 76% were willing to vaccinate their child if the vaccine is for free and 63% were willing to vaccinate even if the vaccine comes with a cost. Having heard of HPV was associated with both willingness to vaccinate if the vaccine is free (odds ratio [OR]: 1.42; 95% confidence interval [CI]: 1.21-1.66) and willingness to vaccinate even if the vaccine is not free (OR: 1.96; 95% CI: 1.75-2.20) compared with those who never heard of HPV. Beliefs about vaccine safety and efficacy were also strong correlates of willingness to vaccinate. Parents born outside Europe and those with higher education were less willing to vaccinate if the vaccine is not free. In conclusion, the willingness to vaccinate was reasonably high and cost did not appear to be a major barrier. Information about vaccine safety and efficacy is important and parents need information about HPV and the HPV vaccine.

Udgivelsesdato: 2008-Apr-16 BACKGROUND: Long-term deleterious effects of repeated blood donations may be masked by the donors' healthy lifestyle. To investigate possible effects of blood donation and iron loss through blood donation on cancer incidence while minimizing "healthy donor effects," we made dose-response comparisons within a cohort of Swedish and Danish blood donors. METHODS: We used a nested case-control study design, in which case patients were defined as all donors who were diagnosed with a malignancy between their first recorded blood donation and study termination (n = 10866). Control subjects (n = 107140) were individually matched on sex, age, and county of residence. Using conditional logistic regression, we estimated relative risks of cancer according to number of blood donations made or estimated iron loss 3-12 years before a case patient was diagnosed with cancer. All statistical tests were two-sided. RESULTS: No clear association was observed between number of donations and risk of cancer overall. However, between the lowest (< or = median, < 0.75 g) and highest (> 90th percentile, > 2.7 g) categories of estimated iron loss, there was a trend (P(trend) < .001) of decreasing risk for cancers of the liver, lung, colon, stomach, and esophagus, which are thought to be promoted by iron overload (combined odds ratio [OR] = 0.70, 95% confidence interval [CI] = 0.58 to 0.84), but only among men and only with a latency of 3-7 years. The risk of non-Hodgkin lymphoma was higher among frequent plasma donors (> 25 vs 0 donations, OR = 2.14, 95% CI = 1.22 to 3.74). CONCLUSIONS: Repeated blood donation was not associated with increased or decreased risk of cancer overall. The lack of consistency across latency periods casts doubt on an apparent association between reduced cancer risk and iron loss in men. The positive association between frequent plasma donation and risk of non-Hodgkin lymphoma deserves further exploration.

Knowledge of female sex workers' (FSW) condom use behaviors in Vietnam is important for predicting the epidemic and designing interventions. Four hundred FSWs in Hanoi were studied in 2002. Consistent condom use in the past month was higher with irregular clients (62%), less with regular clients (41%), and lowest with "love mates" (5%). Reasons for not using condoms were partner objection, condom unavailability, and belief of partner's disease-free status. Twenty-seven percent reported not always having a condom available. Thirty-five percent reported increasing condom use in the previous 6 months. Reluctance to ask clients to use condoms and condom unavailability were independently associated with inconsistent condom use with both irregular and regular clients. Older age was also associated with inconsistent condom use with irregular clients. Condom promotion should focus on FSWs and their partners. Negative attitudes toward FSWs and condom promotion need to be changed to reduce stigmatization of FSWs and to make condom use a norm in the society.

Purpose To assess awareness and knowledge of human papillomavirus (HPV) in the adult Swedish population. Methods A cross-sectional study among young adults aged 18–30 years and the parents of children aged 12–15 years was conducted in 2007 to collect information on awareness and knowledge of HPV. Correlates of HPV knowledge were investigated. Results Awareness of cervical cancer and condyloma were high but awareness of HPV was low. Many participants were uncertain or did not know about the causal relation between HPV and condyloma, and cancers other than cervical cancer. Among parents, gender, age, country of origin, and education were the most important correlates of HPV knowledge. Among young adults, these factors were gender, income, and education. Conclusions HPV education campaigns should particularly target young men and those with low education. Educational messages should clarify the risk of HPV, and the causal relationship between HPV and condyloma, and other cancers.

BACKGROUND:When varicella vaccine was licensed in the United States in 1995, there were concerns that childhood vaccination might increase the number of adolescents susceptible to varicella and shift disease toward older age groups where it can be more severe.METHODS:We conducted a series of 5 cross-sectional studies in 1994 to 1995 (prevaccine), 2000, 2003, 2006, and 2009 in Kaiser Permanente of Northern California to assess changes in varicella epidemiology in children and adolescents, as well as changes in varicella hospitalization in people of all ages. For each study, information on varicella history and varicella occurrence during the past year was obtained by telephone survey from a sample of ∼8000 members 5 to 19 years old; varicella hospitalization rates were calculated for the entire membership.RESULTS:Between 1995 and 2009, the overall incidence of varicella in 5- to 19-year-olds decreased from 25.8 to 1.3 per 1000 person-years, a ∼90% to 95% decline in the various age categories (5–9, 10–14, and 15–19 years of age). The proportion of varicella-susceptible children and adolescents also decreased in all age groups, including in 15- to 19-year-olds (from 15.6% in 1995 to 7.6% in 2009). From 1994 to 2009, age-adjusted varicella hospitalization rates in the general member population decreased from 2.13 to 0.25 per 100 000, a ∼90% decline.CONCLUSIONS:In the 15 years after the introduction of varicella vaccine, a major reduction in varicella incidence and hospitalization was observed with no evidence of a shift in the burden of varicella to older age groups.

Cancer patients tend to have a higher incidence of herpes zoster (HZ), but little is known about their risk of HZ complications. We conducted a retrospective study of 424 newly diagnosed hematologic (HM, n = 140) and solid tumor malignancy (STM, n = 284) patients who developed HZ between January 2001 and December 2006 to measure the frequency and identify risk factors of HZ complications. Patients were adult members of Kaiser Permanente Northern California. HZ diagnosis and complications were confirmed by medical chart review. HM patients with HZ tended to have more HZ complications than STM patients (34% vs 23%, p = 0.02), largely due to more frequent non-pain complications. On multivariate analysis, older age and being male were associated with a higher risk of HZ complications in HM patients; more advanced cancer stage was associated with HZ complications in STM patients. HZ complications are frequent and can present extra disease burden in cancer patients who develop HZ.

BACKGROUND: Varicella vaccine was licensed in the United States in 1995 for individuals ≥12 months of age. A second dose was recommended in the United States in June 2006. Varicella incidence and vaccine effectiveness were assessed in a 14-year prospective study conducted at Kaiser Permanente Northern California. METHODS: A total of 7585 children vaccinated with varicella vaccine in their second year of life in 1995 were followed up prospectively for breakthrough varicella and herpes zoster (HZ) through 2009. A total of 2826 of these children received a second dose in 2006–2009. Incidences of varicella and HZ were estimated and compared with prevaccine era rates. RESULTS: In this cohort of vaccinated children, the average incidence of varicella was 15.9 per 1000 person-years, nine- to tenfold lower than in the prevaccine era. Vaccine effectiveness at the end of the study period was 90%, with no indication of waning over time. Most cases of varicella were mild and occurred early after vaccination. No child developed varicella after a second dose. HZ cases were mild, and rates were lower in the cohort of vaccinated children than in unvaccinated children during the prevaccine era (relative risk: 0.61 [95% confidence interval: 0.43–0.89]). CONCLUSIONS: This study confirmed that varicella vaccine is effective at preventing chicken pox, with no waning noted over a 14-year period. One dose provided excellent protection against moderate to severe disease, and most cases occurred shortly after the cohort was vaccinated. The study data also suggest that varicella vaccination may reduce the risks of HZ in vaccinated children.

Background: Given the limited literature, we conducted a study to examine the epidemiology of herpes zoster (HZ) among newly diagnosed cancer patients. Methods: We identified adult health plan members of Kaiser Permanente Northern California diagnosed with invasive cancer from 2001 to 2005. Electronic health records with inpatient and outpatient diagnoses, laboratory tests, and antiviral medications were used to identify HZ diagnoses from 2001 to 2006. HZ diagnoses and associated complications were confirmed by medical chart review. Treatment with chemotherapy and corticosteroids was used to classify patients by immunosuppression level. Results: Among 14,670 cancer patients, 424 were diagnosed with HZ during follow-up (median 22 months). The incidence of HZ was 31/1,000 person-year (PY) in patients with hematologic malignancies and 12/1,000 PY in patients with solid tumors. The corresponding 2-year cumulative incidence of HZ was approximately 6% and 2%, respectively. Compared with incidence rates of HZ reported in a general US population, the age- and sex-standardized rates of HZ were 4.8 times higher [95% confidence interval (CI), 4.0–5.6] in patients with hematologic malignancies and 1.9 times higher (95% CI, 1.7–2.1) in those with solid tumors. HZ risk increased with increasing level of immunosuppression. Among HZ cases, 19% with hematologic malignancies and 14% with solid tumors had HZ-associated pain for at least 30 days. The corresponding numbers for nonpain-related complications were 30% and 18%, respectively. Conclusions: Cancer patients are at substantially increased risk of HZ and among those with HZ, complications are relatively common. Impact: Better HZ prevention and treatment options for cancer patients are needed. Cancer Epidemiol Biomarkers Prev; 22(1); 82–90. ©2012 AACR.

Background Zostavax™ is a live, attenuated varicella-zoster virus vaccine indicated for the prevention of herpes zoster (shingles). An observational post-licensure (Phase IV) study was conducted at Kaiser Permanente Northern California (KPNC), a US managed care organization, to assess the safety of zoster vaccine in people 60 years of age or older, vaccinated in routine medical care. Methods We performed a cohort study, comparing rates of clinical events resulting in hospitalizations or emergency department visits in a 42-day risk time period immediately following vaccination with rates in the same cohort in a subsequent comparison time period. The study data were reviewed and interpreted by an external safety review committee of 3 independent experts. Results Approximately 29,000 people ≥ 60 years of age were vaccinated with zoster vaccine from July 2006 to November 2007. Of the 386 comparisons performed for the main analysis, 4 had an increased relative risk with a nominal p -value ≤ 0.05. After medical records review, the timing of these conditions and procedures was found to be often prior to vaccination, and no clear increase in health events was observed in the risk period following vaccination compared to later. Persons receiving zoster vaccine appeared to be in their optimal health at the time of vaccination, which led to an apparent protective effect of the vaccine for some health outcomes, due to the study design. Conclusions There was no evidence of a safety concern for zoster vaccine.

BACKGROUND: Blood transfusions may influence the recipients' cancer risks both through transmission of biologic agents and by modulation of the immune system. However, cancer occurrence in transfusion recipients remains poorly characterized. METHODS: We used computerized files from Scandinavian blood banks to identify a cohort of 888,843 cancer-free recipients transfused after 1968. The recipients were followed from first registered transfusion until the date of death, emigration, cancer diagnosis, or December 31, 2002, whichever came first. Relative risks were expressed as ratios of the observed to the expected numbers of cancers, that is, standardized incidence ratios (SIRs), using incidence rates for the general Danish and Swedish populations as a reference. All statistical tests were two-sided. RESULTS: During 5,652,918 person-years of follow-up, 80,990 cancers occurred in the transfusion recipients, corresponding to a SIR of 1.45 (95% confidence interval [CI] = 1.44 to 1.46). The SIR for cancer overall decreased from 5.36 (95% CI = 5.29 to 5.43) during the first 6 months after transfusion to 1.10 or less for follow-up periods more than 2 years after the transfusion. However, the standardized incidence ratios for cancers of the tongue, mouth, pharynx, esophagus, liver, and respiratory and urinary tracts and for squamous cell skin carcinoma remained elevated beyond 10 years after the transfusion. CONCLUSIONS: The marked increase in cancer risk shortly after a blood transfusion may reflect the presence of undiagnosed occult cancers with symptoms that necessitated the blood transfusion. The continued increased risk of tobacco- and alcohol-related cancers suggests that lifestyle and other risk factors related to conditions prompting transfusion rather than transfusion-related exposures per se are important to the observed cancer occurrence in the recipients Udgivelsesdato: 2007-Dec-19

BACKGROUND: Although mechanisms for detection of short-term complications after blood transfusions are well developed, complications with delayed onset, notably transmission of chronic diseases such as cancer, have been difficult to assess. Our aim was to investigate the possible risk of cancer transmission from blood donors to recipients through blood transfusion. METHODS: We did a register-based retrospective cohort study of cancer incidence among patients who received blood from donors deemed to have a subclinical cancer at the time of donation. These precancerous donors were diagnosed with a cancer within 5 years of the donation. Data from all computerised blood bank registers in Sweden and Denmark gathered between 1968 and 2002 were merged into a common database. Demographic and medical data, including mortality and cancer incidence, were ascertained through linkages with nationwide, and essentially complete, population and health-care registers. The risk of cancer in exposed recipients relative to that in recipients who received blood from non-cancerous donors was estimated with multivariate Poisson regression, adjusting for potential confounding factors. FINDINGS: Of the 354 094 transfusion recipients eligible for this analysis, 12,012 (3%) were exposed to blood products from precancerous donors. There was no excess risk of cancer overall (adjusted relative risk 1.00, 95% CI 0.94-1.07) or in crude anatomical subsites among recipients of blood from precancerous donors compared with recipients of blood from non-cancerous donors. INTERPRETATION: Our data provide no evidence that blood transfusions from precancerous blood donors are associated with increased risk of cancer among recipients compared with transfusions from non-cancerous donors Udgivelsesdato: 2007-May-19

The heat stability of hepatitis B vaccine (HepB vaccine) should enable its storage outside the cold chain (OCC), increasing access to the birth dose in areas lacking refrigeration. We compared the immunogenicity of a locally produced vaccine among infants who received three doses stored within the cold chain (n = 358) or for whom the first dose was stored OCC for up to one month (n = 748). Serum was collected from these infants at age 9-18 months. The vaccine was protective in 80.3% of all infants. There were no differences in the prevalence of a protective level of antibody or antibody titer among groups of infants according to storage strategy. Differences in antibody titer between certain groups of infants could be explained by different vaccination schedules. Where birth dose coverage will be improved, HepB vaccine can be taken OCC for up to one month without affecting its immunogenicity.

The prevalence of HIV/sexually transmitted diseases (STDs) was determined, the risk characteristics examined, and factors associated with HIV infection identified among noninstitutionalized female sex workers (FSWs), using a cross-sectional survey with 2-stage cluster sampling. Four hundred FSWs were interviewed face to face using a structured questionnaire and tested for HIV, syphilis, Chlamydia infection, and gonorrhea. HIV seroprevalence was 12%, syphilis 17% (using the treponemal pallidum hemagglutination assay), Chlamydia infection 3.8% (using polymerase chain reaction [PCR]), and gonorrhea 6.3% (PCR). Lower-class FSWs averaged 2 clients per day, and middle-class FSWs about 1.2. Median duration in sex work was 2.3 years. Consistent condom use was 63% with irregular clients, 41% with regular clients, and only 4.8% with “love mates.” Fifty-five percent had had sex with a drug user(s). Thirty-eight percent used drugs, of whom 83% injected. Factors associated with HIV included being young, having a low level of education, longer residence in Hanoi, being a lower-class FSW, having higher income compared with peers, perception of self being at low risk for HIV, poor knowledge of HIV, and sharing injecting equipment. Intervention strategies should include reduction of both stigmatization and sharing of drug paraphernalia, promotion of nonstigmatizing voluntary testing and counseling, and aggressive marketing and promotion of condoms.

Aims To describe the drug use practices among female sex workers (FSWs) in Hanoi and to identify factors associated with their drug injecting. Design, setting and particicipants A two-stage cluster survey of 400 FSWs was conducted from June to September, 2002. Participating FSWs were both establishment- (160) and street-based (240), who were practising in seven urban and one suburban districts of Hanoi. Measurements Subjects were interviewed face to face using a structured questionnaire. Findings Among the middle-class FSWs, 27% used drugs, of whom 79% injected. Among low-class FSWs, 46% used drugs and 85% injected. Among drug-using FSWs, 86% had started using drugs within the past 6 years. Among drug-injecting FSWs, 81% had started injecting within the past 4 years. Clean- ing of injecting equipment was not common among those who shared. Having drug-injecting 'love mates', drug-using clients, longer residence in Hanoi, more clients and not currently cohabiting were found to be independently associated with drug injecting among FSWs. Conclusions The high prevalence of injecting drug use among FSWs makes them susceptible to HIV infection, and is a threat to their clients. There is a strong relationship between drug-using FSWs and male drug-using clients and non-client partners. Intervention to prevent drug use initiation among non- drug-using FSWs and harm reduction among drug-using FSWs are urgently

Background Suicidal thought is a risk factor and a stage in the suicidal process from planning to attempting and dying by suicide. To date, studies on suicidal thought in the general population, especially in Asian communities, have been limited. Method The WHO SUPRE-MISS (the multisite intervention study on suicidal behaviours) community survey questionnaire was filled in for 2,280 randomly selected residents of the DongDa district of Hanoi, Vietnam by means of face-to-face interviews. This multi-factor questionnaire includes such variables as sociodemographic information, suicidal thought and history of suicide attempts, physical health, alcohol consumption and medication. Results Prevalence rates for life time suicidal thoughts, suicide plans and suicide attempts were 8.9%, 1.1% and 0.4% respectively. Suicidal thoughts are associated with multiple characteristics, such as female gender, single/widowed/separated/divorced marital status, low income, lifestyle (use of alcohol, sedatives and pain relief medication), but not with low education or employment status. Having no religion and being a Buddhist appear to be protective factors for suicidal thought. The ratio of suicidal thoughts, suicide plans and suicide attempts on a lifetime basis is 22.3:2.8:1. Conclusion In Vietnam, as in Western and other Asian countries, suicidal thoughts are associated with similar negative psychosocial risk factors, lifestyle and emotional problems, which implies that suicide preventive measure developed elsewhere can be adjusted to Vietnamese condition. Understanding the unique and common risks in a culture may assist in prediction and control.