Global evaluation of lineage-specific human papillomavirus capsid antigenicity using antibodies elicited by natural infection

Human Papillomavirus (HPV) type variants have been classified into lineages and sublineages based upon their whole genome sequence. Here we have examined the specificity of antibodies generated following natural infection with lineage variants of oncogenic types (HPV16, 18, 31, 33, 45, 52 and 58) by testing serum samples assembled from existing archives from women residing in Africa, The Americas, Asia or Europe against representative lineage-specific pseudoviruses for each genotype. We have subjected the resulting neutralizing antibody data to antigenic clustering methods and created relational antigenic profiles for each genotype to inform the delineation of lineage-specific serotypes. For most genotypes, there was evidence of differential recognition of lineage-specific antigens and in some cases of a sufficient magnitude to suggest that some lineages should be considered antigenically distinct within their respective genotypes. These data provide compelling evidence for a degree of lineage specificity within the humoral immune response following natural infection with oncogenic HPV.

Can we use postal surveys with anonymous testing to monitor chlamydia prevalence in young women in England? Pilot study incorporating randomised controlled trial of recruitment methods

OBJECTIVES

Chlamydia prevalence in the general population is a potential outcome measure for the evaluation of chlamydia control programmes. We carried out a pilot study to determine the feasibility of using a postal survey for population-based chlamydia prevalence monitoring.

METHODS

Postal invitations were sent to a random sample of 2000 17-year-old to 18-year-old women registered with a general practitioner in two pilot areas in England. Recipients were randomised to receive either a self-sampling kit (n=1000), a self-sampling kit and offer of £5 voucher on return of sample (n=500) or a self-sampling kit on request (n=500). Participants returned a questionnaire and self-taken vulvovaginal swab sample for unlinked anonymous Chlamydia trachomatis testing. Non-responders were sent a reminder letter 3 weeks after initial invitation. We calculated the participation rate (number of samples returned/number of invitations sent) and cost per sample returned (including cost of consumables and postage) in each group.

RESULTS

A total of 155/2000 (7.8%) samples were returned with consent for testing. Participation rates varied by invitation group: 7.8% in the group who were provided with a self-sampling kit, 14% in the group who were also offered a voucher and 1.0% in the group who were not sent a kit. The cost per sample received was lowest (£36) in the group who were offered both a kit and a voucher.

CONCLUSIONS

The piloted survey methodology achieved low participation rates. This approach is not suitable for population-based monitoring of chlamydia prevalence among young women in England.

STUDY REGISTRATION NUMBER

(UKCRN ID 10913).

Confirmatory assays are essential when using molecular testing for Neisseria gonorrhoeae in low-prevalence settings: insights from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3)

OBJECTIVES

To investigate the occurrence of unconfirmed positive gonorrhoea results when using molecular testing within a large population-based survey.

DESIGN, SETTING AND PARTICIPANTS

Between 2010 and 2012, we did a probability sample survey of 15,162 men and women aged 16-74 years in Britain. Urine from participants aged 16-44 years reporting ≥1 lifetime sexual partner was tested for Neisseria gonorrhoeae and Chlamydia trachomatis using the Aptima Combo 2 (AC2) assay, with positive or equivocal results confirmed with molecular assays using different nucleic acid targets.

RESULTS

A total of 4550 participants aged 16-44 years had urine test results (1885 men; 2665 women). For gonorrhoea, 18 samples initially tested positive and eight were equivocal. Only five out of 26 confirmed, giving a positive predictive value (PPV) for the initial testing of 19% (95% CI 4% to 34%). Most (86% (18/21)) participants with unconfirmed positive results for gonorrhoea reported zero or one sexual partner without condoms in the past year and none had chlamydia co-infection, whereas all five with confirmed gonorrhoea reported at least two recent sexual partners without condoms, and four had chlamydia co-infection. The weighted prevalence for gonorrhoea positivity fell from 0.4% (0.3% to 0.7%) after initial screening to <0.1% (0.0% to 0.1%) after confirmatory testing. By comparison, 103 samples tested positive or equivocal for chlamydia and 98 were confirmed (PPV=95% (91% to 99%)).

CONCLUSIONS

We highlight the low PPV for gonorrhoea of an unconfirmed reactive test when deploying molecular testing in a low-prevalence population. Failure to undertake confirmatory testing in low-prevalence settings may lead to inappropriate diagnoses, unnecessary treatment and overestimation of population prevalence.

Prevalence, risk factors, and uptake of interventions for sexually transmitted infections in Britain: findings from the National Surveys of Sexual Attitudes and Lifestyles (Natsal)

BACKGROUND

Population-based estimates of prevalence, risk distribution, and intervention uptake inform delivery of control programmes for sexually transmitted infections (STIs). We undertook the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3) after implementation of national sexual health strategies, and describe the epidemiology of four STIs in Britain (England, Scotland, and Wales) and the uptake of interventions.

METHODS

Between Sept 6, 2010 and Aug 31, 2012, we did a probability sample survey of 15,162 women and men aged 16-74 years in Britain. Participants were interviewed with computer-assisted face-to-face and self-completion questionnaires. Urine from a sample of participants aged 16-44 years who reported at least one sexual partner over the lifetime was tested for the presence of Chlamydia trachomatis, type-specific human papillomavirus (HPV), Neisseria gonorrhoeae, and HIV antibody. We describe age-specific and sex-specific prevalences of infection and intervention uptake, in relation to demographic and behavioural factors, and explore changes since Natsal-1 (1990-91) and Natsal-2 (1999-2001).

FINDINGS

Of 8047 eligible participants invited to provide a urine sample, 4828 (60%) agreed. We excluded 278 samples, leaving 4550 (94%) participants with STI test results. Chlamydia prevalence was 1·5% (95% CI 1·1-2·0) in women and 1·1% (0·7-1·6) in men. Prevalences in individuals aged 16-24 years were 3·1% (2·2-4·3) in women and 2·3% (1·5-3·4) in men. Area-level deprivation and higher numbers of partners, especially without use of condoms, were risk factors. However, 60·4% (45·5-73·7) of chlamydia in women and 43·3% (25·9-62·5) in men was in individuals who had had one partner in the past year. Among sexually active 16-24-year-olds, 54·2% (51·4-56·9) of women and 34·6% (31·8-37·4) of men reported testing for chlamydia in the past year, with testing higher in those with more partners. High-risk HPV was detected in 15·9% (14·4-17·5) of women, similar to in Natsal-2. Coverage of HPV catch-up vaccination was 61·5% (58·2-64·7). Prevalence of HPV types 16 and 18 in women aged 18-20 years was lower in Natsal-3 than Natsal-2 (5·8% [3·9-8·6] vs 11·3% [6·8-18·2]; age-adjusted odds ratio 0·44 [0·21-0·94]). Gonorrhoea (<0·1% prevalence in women and men) and HIV (0·1% prevalence in women and 0·2% in men) were uncommon and restricted to participants with recognised high-risk factors. Since Natsal-2, substantial increases were noted in attendance at sexual health clinics (from 6·7% to 21·4% in women and from 7·7% to 19·6% in men) and HIV testing (from 8·7% to 27·6% in women and from 9·2% to 16·9% in men) in the past 5 years.

INTERPRETATION

STIs were distributed heterogeneously, requiring general and infection-specific interventions. Increases in testing and attendance at sexual health clinics, especially in people at highest risk, are encouraging. However, STIs persist both in individuals accessing and those not accessing services. Our findings provide empirical evidence to inform future sexual health interventions and services.

FUNDING

Grants from the UK Medical Research Council and the Wellcome Trust, with support from the Economic and Social Research Council and the Department of Health.

PP082. Ophthalmic artery doppler for identification of severe preeclampsia in pregnancies complicated by hypertension

INTRODUCTION

Hypertension is the most common disorder that occurs during pregnancy and one of the main causes of maternal mortality worldwide. Among the hypertensive disorders that affect pregnancy, preeclampsia (PE) is the major cause of maternal mortality, maternal morbidity, perinatal death, prematurity and intrauterine growth restriction. The acute cerebral complications in PE account for at least 75% of maternal death. Central nervous system hemodynamic modifications in PE are a controversial issue. Neurological involvement in PE-eclampsia syndrome fulfills the criteria of posterior reversible encephalopathy syndrome (PRES). The pathophysiology of PRES is still under investigation. Assessment of cerebral circulation is challenging. Noninvasive techniques, especially transcranial Doppler sonography, are becoming more widely used to evaluate cerebral flow. Ophthalmic artery Doppler is a noninvasive examination used to study central vascular flow that has been shown to be a promising method in the evaluation of pregnant women with hypertension.

OBJECTIVES

The aim of this study was to compare the ophthalmic artery Doppler indices observed in singleton pregnant women complicated by hypertension (study group) and to correlate the indices observed in hypertensive pregnant women with those observed in normal pregnant women (control group).

METHODS

Ophthalmic artery Doppler indices of 30 mild and 30 severe pre-eclamptic women and 30 pregnant women with chronic hypertension (CH) at 20-40weeks of gestational age (GA) were compared. The control group consisted of 289 healthy pregnant women. Resistance index (RI), pulsatility index (PI), and peak ratio (PR) were determined in the right eye. The mean and SD were calculated for each group. Analysis of variance (ANOVA) was used to compare Doppler indexes means between groups. As significant differences were determined by ANOVA analysis, each group was compared by the Tukey method. Receiver operating characteristics (ROC) curves were used to determine the predictive power of ophthalmic artery Doppler indexes for the identification of severe pre-eclamptic women. P<0.05 was considered statistically significant.

RESULTS

Significant differences were found between the values obtained for RI, PI, and PR in severe PE women compared to the other groups (study and control). The mean and SD for IR, IP and PR in mild PE, severe PE and CH groups were respectively 0.73 (±0.06), 1.63 (±0.35) and 0.65 (±0.10); 0.63 (±0.09), 1.13 (±0.31) and 0.89 (±0.12); 0.73 (±0.07), 1.66 (±0.49) and 0.66 (±0.14). The mean and SD for IR, IP and PR in normotensive pregnant women were 0.75 (±0.05), 1.88 (±0.43), 0.52 (±0.10). The optimal cut-off values for IR, IP and PR for the identification of severe pre-eclamptic women determined by roc curves was 0.657, 1.318, 0.784 (sensitivity and specificity were 0.633 and 0.919, 0.733 and 0.888, 0.833 and 0.974, respectively). The area under the ROC curve for IR was 0.787(95% CI: 0.68-0.89), for IP was 0.797 (95% CI: 0.69-0.90) and for PR was 0.886 (95% CI: 0.80-0.96).

CONCLUSION

Ophthalmic Doppler is a useful method in the identification of severe PE. PR was best ophthalmic Doppler index at discriminating between severe PE and pregnant women with mild PE or chronic hypertension as determined by roc curve.

Still no evidence of new variant Chlamydia trachomatis in England and Wales

Background: New variant Chlamydia trachomatis (nvCT) remains an important public health concern and in 2008 four cases of nvCT were reported in Scotland. The present study set out to determine whether nvCT was present in England and Wales. Methods: 1054 clinical specimens, which had been confirmed as chlamydia positive (using an nvCT unaffected platform) at nine different diagnostic laboratories throughout England and Wales, were examined for the presence of the 377 bp nvCT deletion. Results: 92% (968/1054) of specimens examined were confirmed as wild-type C. trachomatis. The remaining 86 specimens were found to be untypeable, which was probably due to low levels of DNA. No nvCT specimens were identified. Conclusions: There is currently no evidence that nvCT is present in England and Wales; however, laboratories using nvCT-affected platform should remain vigilant.