Seroprevalence and genital DNA prevalence of HPV types 6, 11, 16 and 18 in a cohort of young Norwegian women: study design and cohort characteristics.

BACKGROUND: Long-term efficacy evaluations of a quadrivalent HPV type 6/11/16/18 vaccine are ongoing in the Nordic region. As there are limited epidemiological data on HPV infection in Norway, we determined prevalence and identified sociobehavioural correlates of HPV 6/11/16/18 infection in young Norwegian women. METHODS: Norwegian (n=898) women, aged 1624 years, were enrolled in a 4-year prospective study. At enrolment and at 6-month intervals thereafter, an interview on behavioural data and a gynaecological examination were undertaken. Genital samples were tested for the L1,E6 and E7 genes of HPV-6/11/16/18, and serum anti-HPV-6/11/16/18 levels were measured using a competitive Luminex immunoassay (cLIA). Results. DNA and seroprevalence of HPV 6, 11, 16 or 18 ranged from 0.9 to 16.3% and 2.6 to 16.2%,respectively; and most infected women (approximately 75%) were infected with only 1 type. Of the HPV DNA positive cases, 54.3, 50.0,47.3 and 38.5% had detectable HPV 6, 11, 16 or 18 antibodies, respectively. More than 50% of the high-grade cervical intraepithelial neoplasia (CIN) cases were HPV-16 or HPV-18 DNA positive. Lifetime number of partners was the strongest and only predictor of sero- and DNA-positivity across the 4 HPV types. CONCLUSION: Given the high prevalence of HPV infection among young women with mostly single-type infection, and the fact that type-specific HPV screening is not recommended prior to the administration of the quadrivalent HPV vaccine, our data suggest the importance of widespread,rather than targeted, immunisation.

[Chlamydia infections and sexual behavior among young women]. / Chlamydiainfeksjon og seksualatferd blant unge kvinner.

BACKGROUND: We wanted to determine the prevalence of Chlamydia trachomatis in a sample of young women and to assess risk factors related to sexual behaviour that are predictive of such infection. MATERIAL AND METHODS: 898 healthy, non-pregnant women aged 16 to 24 years attending primary care centres over a two-year period (September 1998 to December 2000) were recruited for the study. Uterine cervix samples were tested for Chlamydia trachomatis and participants were interviewed about their sexual behaviour. Chlamydia test results from 881 samples were valid. RESULTS: The prevalence of genital Chlamydia trachomatis infection was 2.4% (21/881). In univariable analyses, a high number of lifetime partners (four or more), smoking, previous pregnancy and a previous positive chlamydia test were factors predictive of a positive Chlamydia test. In multivariable analyses, previous pregnancy and a previous positive Chlamydia test were the only significant factors. The number of lifetime partners was higher among women who had been pregnant or previously had tested positively for Chlamydia. INTERPRETATION: The prevalence of Chlamydia was low in this population. Risk behaviour (frequent change of partners) can be expressed by teenage pregnancy and positive Chlamydia test results and these factors can be used for identification of women who should be tested more frequently than others for Chlamydia infection in a low-prevalence population.

[Chlamydia trachomatis--pattern of testing and prevalence among young women]. / Chlamydia trachomatis--prøvetakingsmønster og prevalens blant unge kvinner.

BACKGROUND: The purpose of this study was to explore pattern of testing and prevalence of C trachomatis among 16 to 19 year old Norwegian high school girls. MATERIAL AND METHODS: The study subjects were 827 girls who participated in a study of oral contraceptives prescribed by public health nurses. The first consultation was an interview about sexual behaviour and other characteristics. The participants were encouraged to test for C trachomatis with their general practitioners. We explored characteristics of those tested and predictors of genital C trachomatis infection. RESULTS: Half of the study population was tested, either before (21%) or during the study period (26%). Girls with risk factors such as change of partner over the last six months, older partner or no regular partner were more likely to be tested than girls with no change of partner or a regular same-age partner. One out of four girls with high-risk behaviour (> or =3 partners) was never tested. The prevalence of infection at first test was 9%. The risk for having a positive test result was three times higher for single girls than for girls with a regular same-age partner. INTERPRETATION: Too few young girls were tested for C trachomatis. Encouragement from public health providers had low influence on the pattern of testing. Alternative strategies such as implementation of do-it-yourself tests by urine or vulvovaginal sampling procedures have to be provided as a low-threshold service.