Point-of-care SARS-CoV-2 serological assays for enhanced case finding in a UK inpatient population.

Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. Case identification is currently made by real-time polymerase chain reaction (PCR) during the acute phase and largely restricted to healthcare laboratories. Serological assays are emerging but independent validation is urgently required to assess their utility. We evaluated five different point-of-care (POC) SARS-CoV-2 antibody test kits against PCR, finding concordance across the assays (n = 15). We subsequently tested 200 patients using the OrientGene COVID-19 IgG/IgM Rapid Test Cassette and find a sensitivity of 74% in the early infection period (day 5-9 post symptom onset), with 100% sensitivity not seen until day 13, demonstrating inferiority to PCR testing in the infectious period. Negative rate was 96%, but in validating the serological tests uncovered potential false-negatives from PCR testing late-presenting cases. A positive predictive value (PPV) of 37% in the general population precludes any use for general screening. Where a case definition is applied however, the PPV is substantially improved (95.4%), supporting use of serology testing in carefully targeted, high-risk populations. Larger studies in specific patient cohorts, including those with mild infection are urgently required to inform on the applicability of POC serological assays to help control the spread of SARS-CoV-2 and improve case finding of patients that may experience late complications.

New-onset anosmia and ageusia in adult patients diagnosed with SARS-CoV-2 infection.

OBJECTIVES: We investigated the prevalence of anosmia and ageusia in adult patients with a laboratory-confirmed diagnosis of infection with severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2). METHODS: This was a retrospective observational analysis of patients infected with SARS-CoV-2 admitted to hospital or managed in the community and their household contacts across a London population during the period March 1st to April 1st, 2020. Symptomatology and duration were extracted from routinely collected clinical data and follow-up telephone consultations. Descriptive statistics were used. RESULTS: Of 386 patients, 141 (92 community patients, 49 discharged inpatients) were included for analysis; 77/141 (55%) reported anosmia and ageusia, nine reported only ageusia and three only anosmia. The median onset of anosmia in relation to onset of SARS-CoV-2 disease (COVID-19) symptoms (as defined by the Public Health England case definition) was 4 days (interquartile range (IQR) 5). Median duration of anosmia was 8 days (IQR 16). Median duration of COVID-19 symptoms in community patients was 10 days (IQR 8) versus 18 days (IQR 13.5) in admitted patients. As of April 1, 45 patients had ongoing COVID-19 symptoms and/or anosmia; 107/141 (76%) patients had household contacts, and of 185 non-tested household contacts 79 (43%) had COVID-19 symptoms with 46/79 (58%) reporting anosmia. Six household contacts had anosmia only. CONCLUSIONS: Over half of the positive patients reported anosmia and ageusia, suggesting that these should be added to the case definition and used to guide self-isolation protocols. This adaptation may be integral to case findings in the absence of population-level testing. Until we have successful population-level vaccination coverage, these steps remain critical in the current and future waves of this pandemic.

High-fidelity phase and amplitude control of phase-only computer generated holograms using conjugate gradient minimisation.

We demonstrate simultaneous control of both the phase and amplitude of light using a conjugate gradient minimisation-based hologram calculation technique and a single phase-only spatial light modulator (SLM). A cost function, which incorporates the inner product of the light field with a chosen target field within a defined measure region, is efficiently minimised to create high fidelity patterns in the Fourier plane of the SLM. A fidelity of F = 0.999997 is achieved for a pattern resembling an LG10 mode with a calculated light-usage efficiency of 41.5%. Possible applications of our method in optical trapping and ultracold atoms are presented and we show uncorrected experimental realisation of our patterns with F = 0.97 and 7.8% light efficiency.

Proposed parametric cooling of bilayer cuprate superconductors by terahertz excitation.

We propose and analyze a scheme for parametrically cooling bilayer cuprates based on the selective driving of a c-axis vibrational mode. The scheme exploits the vibration as a transducer making the Josephson plasma frequencies time dependent. We show how modulation at the difference frequency between the intrabilayer and interbilayer plasmon substantially suppresses interbilayer phase fluctuations, responsible for switching c-axis transport from a superconducting to a resistive state. Our calculations indicate that this may provide a viable mechanism for stabilizing nonequilibrium superconductivity even above Tc, provided a finite pair density survives between the bilayers out of equilibrium.

Self-reported oral health, dental self-care and dental service use among New Zealand secondary school students: findings from the Youth 07 study.

AIM: The primary aim was to describe New Zealand secondary school students' use of dental services and determine the nature and extent of any inequities by deprivation status and ethnicity. A secondary aim was to to describe their toothbrushing practices and self-reported dental pain experience, past restorative treatment and tooth loss. METHOD: Secondary analysis of data from the cross-sectional Youth 07: National Survey of the Health and Wellbeing of New Zealand Secondary School Students. A representative sample of 9,098 secondary school students aged 13-17 years from 96 secondary schools across New Zealand took part, with a response rate of 73%. Self-report information about oral health care behaviour, past dental experiences and dental visiting pattern was collected. Data analysis took the complex survey design into account, and multivariate analysis was undertaken to examine the associations of dental service-use. RESULTS: A dental visit in the previous 12 months was reported by 72% of participants. The odds of having done so were higher among females, those who brushed at least twice daily, and those who had been kept awake at night by dental pain. Lower odds were seen among students identifying with Maori, Pacific or Asian people (and those in the 'Other' ethnic category) than among European students, and among those residing in medium- or high-deprivation areas than those in lo-deprivation areas. One in seven participants reported having lost a tooth due to oral disease. Having had a tooth filled was reported by almost three-quarters of the sample, and having been kept awake by dental pain at night was reported by just over one in five. Almost two-thirds reported brushing their teeth twice or more in the previous 24 hours, and a small minority had not brushed at all. CONCLUSION: Ethnic and socio-economic inequities in the use of dental services are apparent among New Zealand adolescents.

Comparison of health-risk behaviours among students in alternative high schools from New Zealand and the USA.

OBJECTIVES: To describe the prevalence of health-risk behaviours of New Zealand alternative education students, and to compare these behaviours to similar students in the USA. METHODS: Thirty-six alternative education schools in the northern region of New Zealand were surveyed. A total of 269 students completed a youth health questionnaire using laptop computers. These data were compared to data from an equivalent population of alternative education students in the USA. RESULTS: Alternative education students from New Zealand and the USA engage in similar high levels of health-risk behaviours. Female students in New Zealand are at particularly high risk of poor health and social outcomes due to high levels of alcohol and marijuana use, driving under the influence of alcohol and high prevalence of risky sexual behaviours. Such health-risk behaviours place alternative education students at greater risk of some of the leading causes of morbidity and mortality in both youth and adult populations. CONCLUSIONS: Findings from the present study support the need for specific health policies and programmes for alternative high school students. Providers of New Zealand alternative education should be aware that female students are at particularly high risk of many health-risk behaviours.

Epidemiology of Munchausen syndrome by proxy in New Zealand.

OBJECTIVE: To determine the epidemiology of Munchausen syndrome by proxy (MSBP) in New Zealand and describe the effects of this condition on children and their paediatricians. METHODOLOGY: A mail-out survey was sent to all paediatricians in New Zealand in 1999. Paediatricians were asked to identify all cases of MSBP, non-accidental poisoning or non-accidental suffocation diagnosed or suspected in children less than 16 years of age that had been seen in the past 12 months. Those paediatricians who identified a case were then interviewed by telephone to ensure that identified cases were new cases and that they were unique. RESULTS: Responses were obtained from 148 (95%) of 156 practising paediatricians in New Zealand. Eighteen unique cases of MSBP were identified where the diagnosis had been made in the preceding 12 months. The incidence rate for MSBP in children aged less than 16 years was 2.0/100 000 children. Eleven (61%) of the 18 cases were referred to child protection agencies or the police. The mean time taken to diagnosis from initial presentation was 7 months in the cases referred to child protection agencies and 23 months in cases not referred. The median age at diagnosis was 2.7 years. The mother was the suspected perpetrator in all cases. Most children (72%) presented with multiple symptoms. Over half (55%) had an underlying chronic illness. The morbidity for the child in the majority of cases was not severe, and in nine (50%) cases it was noted that following diagnosis there was improvement or resolution of symptoms. Ten (56%) of the 18 paediatricians involved with cases reported experiencing considerable stress. CONCLUSIONS: The annual incidence in New Zealand of MSBP in children under 16 years is higher than that reported from other countries. Chronic illness is often associated with this condition. The morbidity for the majority of children was not severe and often improved with diagnosis. Paediatricians reported stress and difficulty in association with caring for children with this syndrome of child abuse.

Adolescents' perceptions of a health survey using multimedia computer-assisted self-administered interview.

OBJECTIVE: To ascertain young people's perceptions of an adolescent health survey when administered by multimedia computer assisted self-administered Interview (M-CASI) through analysis of (1) questionnaire item responses and (2) focus group interviews. SETTING: Auckland, New Zealand, 1999. STUDY TYPE: Pilot testing of a 488-item branching questionnaire delivered using a youth-oriented and user-friendly M-CASI interface in a variety of settings using both desktop and laptop computers. Post pilot focus groups of participants identifying their perceptions and experiences of the survey. SAMPLE: 110 school students aged 12 to 18 years. RESULTS: The mean number of questions answered by participants was 316 with the median time to completion being 48 minutes. On average 65% of the total number of questions were seen and of these 1.5% were deliberately not answered. A high level of acceptability and enjoyment of M-CASI was found in the analysis of focus group responses and agreed with the item responses relating to M-CASI within the questionnaire itself. Participants identified privacy and confidentiality as being particularly important for the honesty of their responses. The passive matrix screens of the computers were popular as they could only be viewed from in front. CONCLUSIONS: M-CASI is an acceptable instrument for the administration of a youth health survey. Laptop computers with passive matrix screens are able to enhance perceptions of privacy and confidentiality, which may improve honesty of responses. IMPLICATIONS: M-CASI is now feasible and offers advantages in health surveying.