Breast Cancer Screening Program in Morocco: Status of implementation, organization and performance

Breast Cancer Screening Program was introduced and rolled out in Morocco in 2010. Women between 40 and 69 years are screened at the primary health centers (PHC) with clinical breast examination (CBE). A comprehensive evaluation of the program was conducted in 2016-2017 for quality assurance and mid-term course correction. The evaluation process involved: in-depth interviews of program managers; focus group discussions with service-providers of screening, diagnosis and treatment; supportive supervisory visits to randomly selected PHCs and diagnostic centers; desk review of the national guidelines and other published documents; and analysis of the performance data compiled by the program-in-charge. We found that the program has strong political support, a well-organized management structure and documented national policy and protocol. In absence of a mechanism to identify and invite the eligible women individually, the program is opportunistic in nature. Every PHC is provided with an annual target to be screened. A highly visible annual campaign to educate and motivate women has a major impact on participation. Record keeping and data collection are paper-based. In the years 2015 and 2016, 1.1 and 1.5 million women were screened, respectively. In the year 2015, 62.8% of the annual target population was covered, CBE positivity was 3.2%, a further assessment rate of screen-positive women was 34.1% and the breast cancer detection rate was 1.0/1000 women. Systematic paper-based data collection enabled the assessment of some of the process and outcome indicators. The screening coverage was moderate and the cancer detection rate was low.

Impact of operational factors on HPV positivity rates in an HPV-based screening study in Colombia

OBJECTIVE

To assess the effect of operational factors on the positivity rates of three HPV assays.

METHODS

Within the cross-sectional ESTAMPA study, women aged 30-64 years were recruited at healthcare centers from Soacha, Colombia, during 2012-2015. Cervical samples were collected for cotesting with Hybrid Capture 2 (HC2; Qiagen, Gaithersburg, MD, USA), and either Aptima (Hologic, Marlborough, MA, USA) or Cobas 4800 (Roche Diagnostics, Indianapolis, IN, USA). The effect of operational factors on assay performance was assessed using adjusted positivity rates obtained from logistic regression models.

RESULTS

There were 4168 women included. For samples collected in assay-specific medium, positivity rate differences were associated with the expertise of the nurse collecting the sample (P=0.014 HC2; P=0.091 Aptima) and if sample collection occurred after an initial cytology (P=0.025 HC2; P=0.033 Aptima). If PreservCyt medium (Hologic) was used, HC2 positivity differences were observed depending on the time between sample collection and processing (P=0.026) and on the laboratory technician processing the samples (P=0.003). No differences were observed for PreservCyt samples processed with Aptima or Cobas.

CONCLUSION

Nurse expertise, collection of previous cytology, processing time, and laboratory technician could influence HPV assay performance. Suitable quality assurance protocols for HPV-based screening programs are required. ClinicalTrials.gov: NCT01881659.

Optimization of a Banker Box System to Rear and Release the Parasitoid Habrobracon hebetor (Hymenoptera: Braconidae) for the Control of Stored-Product Moths

Pyralid moths, such as Ephestia kuehniella (Zeller) or Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), are among the pests of most concern in mills and food industries worldwide. One option for their control, which presents an alternative to the application of insecticides, is the release of natural enemies. Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is a larval parasitoid of pyralid moths that is commercially available for augmentative release in storehouses. They are delivered as adults that limit their performance. To improve their quality when released at the target location, a banker box has been developed consisting of a rearing box that optimizes the release of the parasitoid. In the present study, the nonpest larvae Galleria mellonella (L.) (Lepidoptera: Pyralidae) have been used as a host, substituting for E. kuehniella larvae which were used in the previous design. The best results were obtained when a mixture of two larval sizes of the host were offered to the female parasitoid, producing five times more adults than with E. kuehniella larvae. Quality of the released parasitoids was optimal because they were delivered in the pupal stage inside the rearing box and adults began to emerge in situ. The banker box released adult parasitoids over a prolonged period of approximately 25 d at the target location. The use of this banker box may significantly help in the biological control of stored-product moths.

Role of mucosal high-risk human papillomavirus types in head and neck cancers in Romania

BACKGROUND

Limited information is available about the involvement of human papillomavirus (HPV) in head and neck squamous cell carcinomas (HNSCCs) in Romanian patients.

OBJECTIVE

To evaluate the HPV-attributable fraction in HNSCCs collected in Northeastern Romania.

MATERIALS AND METHODS

In total, 189 formalin-fixed paraffin-embedded tissue samples (99 oral cavity tumors, 28 oropharynx, 48 pharynx, and 14 larynx/hypopharynx) were analyzed for HPV DNA and RNA using Luminex-based assays, and for overexpression of p16INK4a (p16) by immunohistochemistry.

RESULTS

Of the 189 cases, 23 (12.2%) were HPV DNA-positive, comprising half of the oropharyngeal cases (14/28, 50.0%) and 9/161 (5.6%) of the non-oropharyngeal cases. HPV16 was the most prevalent HPV type (20/23, 86.9%), followed by HPV18 (5/23, 21.7%) and HPV39 (1/23, 4.3%). Only two (2/189, 1.1%) HNSCC cases were HPV-driven, i.e. positive for both HPV DNA and RNA.

CONCLUSION

A very small subset of HNSCC cases within this cohort from Northeastern Romania appeared to be HPV-driven.

Are two doses of human papillomavirus vaccine sufficient for girls aged 15-18 years? Results from a cohort study in India

Extending two-dose recommendations of HPV vaccine to girls between 15 and 18 years will reduce program cost and improve compliance. Immunogenicity and vaccine targeted HPV infection outcomes were compared between 1795 girls aged 15-18 years receiving two (1-180 days) and 1515 girls of same age receiving three (1-60-180 days) doses. Immunogenicity outcomes in 15-18 year old two-dose recipients were also compared with the 10-14 year old three-dose (N = 2833) and two-dose (N = 3184) recipients. The 15-18 year old two-dose recipients had non-inferior L1-binding antibody titres at seven months against vaccine-targeted HPV types compared to three-dose recipients at 15-18 years and three-dose recipients at 10-14 years of age. Neutralizing antibody titres at 18 months in 15-18 year old two-dose recipients were non-inferior to same age three-dose recipients for all except HPV 18. The titres were inferior to those in the 10-14 year old three-dose recipients for all targeted types. Frequency of incident infections from vaccine-targeted HPV types in the 15-18 year old two-dose recipients was similar to the three dose recipients. None of the girls receiving two or three doses had persistent infection from vaccine-targeted types. These findings support that two doses of HPV vaccine can be extended to girls aged 15-18 years.

Copy number variation (CNV) and insecticide resistance in mosquitoes: evolving knowledge or an evolving problem?

Copy number variation (CNV) in insect genomes is a rich source of potentially adaptive polymorphism which may help overcome the constraints of purifying selection on conserved genes and/or permit elevated transcription. Classic studies of amplified esterases and acetylcholinesterase duplication in Culex pipiens quantified evolutionary dynamics of CNV driven by insecticidal selection. A more complex and potentially medically impactful form of CNV is found in Anopheles gambiae, with both heterogeneous duplications and homogeneous amplifications strongly linked with insecticide resistance. Metabolic gene amplification, revealed by shotgun sequencing, appears common in Aedes aegypti, but poorly understood in other mosquito species. Many methodologies have been used to detect CNV in mosquitoes, but relatively few can detect both duplications and amplifications, and contrasting methods should be combined. Genome scans for CNV have been rare to date in mosquitoes, but offer immense potential to determine the overall role of CNV as a component of resistance mechanisms.

Development and validation of a protocol for optimizing the use of paraffin blocks in molecular epidemiological studies: The example from the HPV-AHEAD study

Worldwide use of formalin-fixed paraffin-embedded blocks (FFPE) is extensive in diagnosis and research. Yet, there is a lack of optimized/standardized protocols to process the blocks and verify the quality and presence of the targeted tissue. In the context of an international study on head and neck cancer (HNC)-HPV-AHEAD, a standardized protocol for optimizing the use of FFPEs in molecular epidemiology was developed and validated. First, a protocol for sectioning the FFPE was developed to prevent cross-contamination and distributed between participating centers. Before processing blocks, all sectioning centers underwent a quality control to guarantee a satisfactory training process. The first and last sections of the FFPEs were used for histopathological assessment. A consensus histopathology evaluation form was developed by an international panel of pathologists and evaluated for four indicators in a pilot analysis in order to validate it: 1) presence/type of tumor tissue, 2) identification of other tissue components that could affect the molecular diagnosis and 3) quality of the tissue. No HPV DNA was found in sections from empty FFPE generated in any histology laboratories of HPV-AHEAD consortium and all centers passed quality assurance for processing after quality control. The pilot analysis to validate the histopathology form included 355 HNC cases. The form was filled by six pathologists and each case was randomly assigned to two of them. Most samples (86%) were considered satisfactory. Presence of >50% of invasive carcinoma was observed in all sections of 66% of cases. Substantial necrosis (>50%) was present in <2% of samples. The concordance for the indicators targeted to validate the histopathology form was very high (kappa > 0.85) between first and last sections and fair to high between pathologists (kappa/pabak 0.21-0.72). The protocol allowed to correctly process without signs of contamination all FFPE of the study. The histopathology evaluation of the cases assured the presence of the targeted tissue, identified the presence of other tissues that could disturb the molecular diagnosis and allowed the assessment of tissue quality.

Role of mucosal high-risk human papillomavirus types in head and neck cancers in central India

Mucosal high-risk (HR) human papillomaviruses (HPV) cause a subset of head and neck cancers (HNC). The HPV-attributable fraction of HNC varies substantially between countries. Although HNC has a very high incidence in the Indian subcontinent, information on the contribution of HPV infection is limited. Here, we evaluated the HPV-attributable fraction in HNC (N = 364) collected in a central region of India. HNC from three different anatomical subsites were included, namely, oral cavity (n = 252), oropharynx (n = 53) and hypopharynx/larynx (n = 59). In this retrospective study, HPV-driven HNC were defined by presence of both viral DNA and RNA. Overexpression of p16INK4a was also evaluated. HR-HPV DNA was detected in 13.7% of the cases; however, only 2.7% were positive for both HPV DNA and RNA. The highest percentage of HPV DNA/RNA double positivity was found in oropharynx (9.4%), followed by larynx (1.7%) and oral cavity (1.6%) (p = 0.02). More than half of HPV DNA/RNA-positive cases were p16INK4a -negative, while a considerable number of HPV RNA-negative cases were p16INK4a -positive (17.9%). HPV16 was the major type associated with HNC (60.0%), although cases positive for HPV18, 35 and 56 were also detected. Our data indicate that the proportion and types of mucosal HR-HPV associated with HNC in this central Indian region differ from those in other (developed) parts of the world. This may be explained by differences in smoking and/or sexual behaviour compared with North America and northern Europe. Moreover, we show that p16INK4a staining appeared not to be a good surrogate marker of HPV transformation in the Indian HNC cases.

Coexistence of zoophytophagous and phytozoophagous strategies linked to genotypic diet specialization in plant bug

Zoophytophagous predators can substitute zoophagy for phytophagy to complete their development and reproduction. In such predators, variation in feeding behaviour is observed both across and within populations. This may be caused by genetic variation in diet specialization, some genotypes specializing on plant resources, whereas others rely mostly on prey to meet their energy and nutriment requirements. We tested the hypothesis that genotypes specialize either on prey or plant resources in the zoophytophagous mullein bug Campylomma verbasci. In the laboratory, we reared 11 isogroup lines of the mullein bug and recorded feeding behaviour on two diets. The first diet was composed of two-spotted spider mites and leaves, and in the second we added pollen, a high-quality vegetal resource. Overall differences in zoophagy among isogroup lines remained consistent regardless of the presence or absence of pollen. While some lines were insensitive to changes in trophic resource composition others switched from prey to pollen feeding when the pollen was available, revealing a negative genetic correlation between the probabilities of feeding on both resources. A significant line by diet interaction in the proportion of time spent feeding on prey in presence or absence of pollen indicated a genetic basis for diet preference. In absence of the preferred resource, nymphs act as generalists, but exhibited individual diet specialisation when facing the choice between high-quality animal and vegetal resources. Results suggest that zoophytophagous predators can exhibit genetic variation in diet preference, which can generate important ecological and economic differences in natural or agricultural systems.

Soliton dual frequency combs in crystalline microresonators

We present a novel compact dual-comb source based on a monolithic optical crystalline MgF₂ multi-resonator stack. The coherent soliton combs generated in the two microresonators of the stack with the repetition rate of 12.1 GHz and difference of 1.62 MHz provided after heterodyning a 300 MHz wide radio frequency comb. An analogous system can be used for dual-comb spectroscopy, coherent LIDAR applications, and massively parallel optical communications.

Phytophagy by the Mullein Bug (Hemiptera: Miridae) on Apples: Feeding Behavior and Fruit Damage

The zoophytophagous mullein bug, Campylomma verbasci (Meyer-Dür) (Hemiptera: Miridae), is a beneficial predator of mites and aphids, but also a pest causing damage when it feeds on apples. The aim of this study was to evaluate three different parameters of phytophagy of the mullein bug both in laboratory (phytophagous behavior) and field (fruit damage) tests: 1) apple cultivar, 2) fruit size, and 3) nymphal instar. In the laboratory, nymphs were observed individually for 15 min in Petri dishes containing agar gel and an apple fruitlet to evaluate feeding punctures of four apple cultivars, four fruit sizes, and five nymphal instars. In the orchard, nymphs were caged at bloom in sleeve cages to evaluate damage on the developing fruit of seven apple cultivars and three nymphal instars on 'Red Delicious'. The feeding punctures in the laboratory were higher on 'Red Delicious' than on 'Honeycrisp'; fruit damage in the orchard did not differ among cultivars at mid-season, but was higher on 'Red Delicious' than on 'Lobo' and 'Marshall McIntosh' at harvest. The number of feeding punctures in the laboratory was higher on 7-9 mm than on 18-20 mm size fruit for 'Red Delicious', but not for 'Honeycrisp'. The number of feeding punctures in the laboratory made by the fifth nymphal instar was higher than those made by younger nymphs, but fruit damage in the orchard did not differ among nymphal instars. Our results will help to elaborate a management chart for this insect by minimizing risks and promoting its use for biocontrol.

RÉSUMÉ

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La punaise de la molène, Campylomma verbasci (Meyer-Dür) (Hemiptera: Miridae), est un prédateur bénéfique zoophytophage des acariens et pucerons dans les vergers, mais également un ravageur causant des dommages lorsqu'il se nourrit sur les pommes. Le but de cette étude était d'évaluer trois paramètres différents sur la phytophagie de la punaise de la molène, à la fois en laboratoire (comportement phytophage) et sur le terrain (dommages aux fruits) : 1) les cultivars de pommes, 2) la taille des fruits, et 3) les stades larvaires. En laboratoire, les larves étaient observées individuellement pendant 15 min dans des boites de Petri contenant un gel d'agar et une jeune pomme afin de déterminer les piqûres de nutrition sur quatre cultivars de pommes, quatre tailles de fruit et cinq stades larvaires différents. En verger, des larves ont été encagées à la floraison dans des manchons en mousseline afin d'évaluer les dommages sur les fruits en développement. Les essais ont été effectués sur sept cultivars de pommes ainsi qu'avec trois stades larvaires sur le cultivar "Délicieuse rouge". Les piqûres de nutrition en laboratoire étaient plus nombreuses sur "Délicieuse rouge" que sur "Honeycrisp"; les dommages aux fruits en verger ne différaient pas entre les cultivars à mi-saison, mais étaient plus nombreux sur "Délicieuse rouge" que sur "Lobo" et "Marshall McIntosh" à la récolte. Les piqûres de nutrition en laboratoire étaient plus nombreuses pour la taille de fruit 7-9 mm que 18-20 mm sur "Délicieuse rouge", mais pas sur "Honeycrisp". Le nombre de piqûres de nutrition (en laboratoire) faites par les larves de stade 5 étaient plus nombreuses que celles faites par les larves plus jeunes, mais les dommages aux fruits (en verger) ne différaient pas entre les stades larvaires. Ces résultats vont aider à élaborer une charte de gestion de cet insecte en minimisant les risques et en favorisant son rôle d'agent de lutte biologique.

Gregarious pupation act as a defensive mechanism against cannibalism and intraguild predation

Coccinellid pupae use an array of defensive strategies against their natural enemies. This study aims to assess the efficiency of gregarious pupation as a defensive mechanism against intraguild predators and cannibals in coccinellid. The study was designed specifically (i) to determine the natural occurrence of gregarious pupation in the field for different coccinellid species, and (ii) to evaluate the adaptive value of gregarious pupation as a defensive mechanism against 2 types of predators (i.e., cannibals and intraguild predators). In the field, gregarious pupation consisted of a group of 2-5 pupae. The proportion of gregarious pupation observed varied according to species, the highest rate being observed with Harmonia axyridis Pallas (Coccinellidae; 14.17%). Gregarious pupation had no impact on the probability that intraguild predators and cannibals locate pupae. Intraguild predation occurred more often in site with gregarious pupation, while cannibalism occurred as often in site with gregarious pupation as in site with isolated pupa. However, for a specific pupa, the mortality rate was higher for isolated pupae than for pupae located in a gregarious pupation site both in the presence of intraguild predators and in the presence of cannibals. The spatial location of pupae within the group had no impact on mortality rate. Since it reduces the risk of predation, it is proposed that gregarious pupation act as a defensive mechanism for H. axyridis pupae.

Breast Cancer Awareness among Middle Class Urban Women--a Community-Based Study from Mumbai, India

Targeting breast cancer awareness along with comprehensive cancer care is appropriate in low and middle income countries like India, where there are no organized and affordable screening services. It is essential to identify the existing awareness about breast cancer in the community prior to launching an organized effort. This study assessed the existing awareness about breast cancer amongst women and their health seeking practices in an urban community in Mumbai, India. A postal survey was undertaken with low or no cost options for returning the completed questionnaires. The majority of the women were aware about cancer but awareness about symptoms and signs was poor. Women were willing to accept more information about cancer and those with higher awareness scores were more likely to seek medical help. They were also more likely to have undergone breast examination in the past and less likely to use alternative medicines. High income was associated with better awareness but this did not translate into better health seeking behaviour. Organized programmes giving detailed information about breast cancer and its symptoms are needed and women from all income categories need to be encouraged for positive change towards health seeking. Further detailed studies regarding barriers to health seeking in India are necessary.

Anastomotic leakage after colon cancer resection: does the individual surgeon matter?

AIM

Anastomotic leakage is one of the most feared complications after colonic resection. Many risk factors for anastomotic leakage have been reported, but the impact of an individual surgeon as a risk factor has scarcely been reported. The aim of this study was to assess if the individual surgeon is an independent risk factor for anastomotic leakage in colonic cancer surgery.

METHOD

This was a retrospective analysis of prospectively collected data from patients who underwent elective resection for colon cancer with anastomosis at a specialized colorectal unit from January 1993 to December 2010. Anastomotic leaks were diagnosed according to standardized criteria. Patient and tumour characteristics, surgical procedure and operating surgeons were analysed. A logistic regression model was used to discriminate statistical variation and identify risk factors for anastomotic leakage.

RESULTS

A total of 1045 patients underwent elective colon cancer resection with primary anastomosis. Anastomotic leakage occurred in 6.4% of patients. Ileocolic anastomosis had an anastomotic leakage rate of 7.2%, colo-colonic/colorectal anastomosis 5.2% and ileorectal anastomosis 12.7%, with intersurgeon variability. The independent risk factors associated with anastomotic leakage were the use of perioperative blood transfusion (OR 2.83, CI 1.59-5.06, P < 0.0001) and the individual surgeon performing the procedure (OR up to 8.44, P < 0.0001).

CONCLUSION

In addition to perioperative blood transfusion, the individual surgeon was identified as an important risk factor for anastomotic leakage. Efforts should be made to reduce performance variability amongst surgeons.

Population Dynamics of the Soybean Aphid (Hemiptera: Aphididae) in Quebec (Canada)

The population dynamics of the soybean aphid ( Aphis glycines Matsumura) was studied over a 12-yr period (2004-2015) from archive and field data collected in the Montérégie area of Quebec (Canada). As observed in the United States, a 2-yr oscillation cycle was observed from 2005 to 2011 in Quebec, with high infestations during odd years, while the opposite was found in 2014 and 2015. A broader pattern could also be observed, with high infestation in two consecutive years every 10 yr. In addition, the infestation intensity observed in high infestation years decreases throughout the years, which questions the evolution of the oscillation cycle in the future.

Organization and evaluation of a pilot cervical cancer screening program in Morocco

OBJECTIVE

To evaluate a pilot program for early detection of cervical cancer using visual inspection with acetic acid (VIA) and the loop electrosurgical excision procedure (LEEP) in one region of Morocco.

METHODS

A descriptive analysis of the screening outcome measures of 43 participating primary care units and one reference center for LEEP was conducted in Meknès-Tafilalet between January 1, 2011, and December 31, 2013. Data on the number of participants, VIA results, colposcopy, and treatment were used in analyses.

RESULTS

Of the 308 197 women in the target age group (30-49 years), 18 586 (6.0%) were screened by VIA. Positive screening test results were recorded for 1628 (8.8%) women, of whom 1144 (70.3%) received diagnostic confirmation by colposcopy. Of the 87 (7.6%) women with cervical intraepithelial neoplasia, only 16 (18.4%) underwent LEEP; three cases of invasive cervical cancer were diagnosed.

CONCLUSION

Issues with implementation of the screening program were found, including low compliance and a low treatment rate of cervical intraepithelial neoplasia by LEEP. By contrast, high rates of colposcopy referral were observed. Screen-and-treat by ablative methods (e.g. thermocoagulation) should be considered to increase treatment rates at national scale-up.

Immunogenicity and HPV infection after one, two, and three doses of quadrivalent HPV vaccine in girls in India: a multicentre prospective cohort study

BACKGROUND

An increase in worldwide HPV vaccination could be facilitated if fewer than three doses of vaccine are as effective as three doses. We originally aimed to compare the immunogenicity and frequency of persistent infection and cervical precancerous lesions caused by vaccine-targeted HPV after vaccination with two doses of quadrivalent vaccine on days 1 and 180 or later, with three doses on days 1, 60, and 180 or later, in a cluster-randomised trial. Suspension of the recruitment and vaccination due to events unrelated to our study meant that some enrolled girls could not be vaccinated and some vaccinated girls received fewer than the planned number of vaccinations by default. As a result, we re-analysed our data as an observational cohort study.

METHODS

Our study was designed to be done in nine locations (188 clusters) in India. Participants were unmarried girls aged 10-18 years vaccinated in four cohorts: girls who received three doses of vaccine on days 1, 60, and 180 or later, two doses on days 1 and 180 or later, two doses on days 1 and 60 by default, and one dose by default. The primary outcomes were immunogenicity in terms of L1 genotype-specific binding antibody titres, neutralising antibody titres, and antibody avidity after vaccination for the vaccine-targeted HPV types 16, 18, 6, and 11 and incident and persistent infections with these HPVs. Analysis was per actual number of vaccine doses received. This study is registered with ISRCTN, number ISRCTN98283094; and with ClinicalTrials.gov, number NCT00923702.

FINDINGS

Vaccination of eligible girls was initiated on Sept 1, 2009, and continued until April 8, 2010. Of 21 258 eligible girls identified at 188 clusters, 17 729 girls were recruited from 178 clusters before suspension. 4348 (25%) girls received three doses, 4979 (28%) received two doses on days 1 and 180 or later, 3452 (19%) received two doses at days 1 and 60, and 4950 (28%) received one dose. Immune response in the two-dose HPV vaccine group was non-inferior to the three-dose group (median fluorescence intensity ratio for HPV 16 1·12 [95% CI 1·02-1·23] and for HPV 18 1·04 [0·92-1·19]) at 7 months, but was inferior in the two-dose default (0·33 [0·29-0·38] for HPV 16 and 0·51 [0·43-0·59] for HPV 18) and one-dose default (0·09 [0·08-0·11] for HPV 16 and 0·12 [0·10-0·14] for HPV 18) groups at 18 months. The geometric mean avidity indices after fewer than three doses by design or default were non-inferior to those after three doses of vaccine. Fewer than three doses by design and default induced detectable concentrations of neutralising antibodies to all four vaccine-targeted HPV types, but at much lower concentration after one dose. Cervical samples from 2649 participants were tested and the frequency of incident HPV 16, 18, 6, and 11 infections was similar irrespective of the number of vaccine doses received. The testing of at least two samples from 838 participants showed that there was no persistent HPV 16 or 18 infections in any study group at a median follow-up of 4·7 years (IQR 4·2-5·1).

INTERPRETATION

Despite the limitations imposed by the suspension of the HPV vaccination, our findings lend support to the WHO recommendation of two doses, at least 6 months apart, for routine vaccination of young girls. The short-term protection afforded by one dose of HPV vaccine against persistent infection with HPV 16, 18, 6, and 11 is similar to that afforded by two or three doses of vaccine and merits further assessment.

FUNDING

Bill & Melinda Gates Foundation.

All-optical stabilization of a soliton frequency comb in a crystalline microresonator

We demonstrate the all-optical stabilization of a low-noise temporal soliton based microresonator based optical frequency comb in a crystalline resonator via a new technique to control the repetition rate. This is accomplished by thermally heating the microresonator with an additional probe laser coupled to an auxiliary optical resonator mode. The carrier-envelope offset frequency is controlled by stabilizing the pump laser frequency to a reference optical frequency comb. We analyze the stabilization by performing an out-of-loop comparison and measure the overlapping Allan deviation. This all-optical stabilization technique can prove useful as an actuator for self-referenced microresonator frequency combs.