Oseltamivir is protective for in-patient mortality in PCR confirmed influenza B and influenza A(H3N2) infections in an historic cohort of 1,048 patients hospitalised during the 2016-17 and 2017-18 influenza seasons.

Standard course oseltamivir 75mg two times daily for five days was associated with an 82% reduction of odds of in-patient death (OR 0.18 (0.07,0.51)) compared to no oseltamivir treatment (OR 1.0 Reference) in a final multivariable logistic regression model of a retrospective cohort of PCR confirmed influenza B and influenza A (H3N2) infected patients admitted to a large UK teaching hospital in influenza seasons 2016-17 and 2017-18. No difference of protective odds for standard course oseltamivir was observed between influenza B and influenza A (H3N2) nor between influenza seasons. These observations strongly support clinical guidelines for molecular testing for respiratory viruses on admission to hospital and prompt treatment of confirmed seasonal influenza B and A with oseltamivir 75mg twice daily for five days.

Social risk factors for SARS-CoV-2 acquisition in university students: cross sectional survey.

The objectives of this study were to define risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in University of Cambridge (UoC) students during a period of increased incidence in October and November 2020. The study design was a survey.Routine public health surveillance identified an increase in the numbers of UoC students with confirmed SARS-CoV-2 positivity in the 10 days after a national lockdown was announced in the UK on 5th November 2020. Cases were identified both through symptom-triggered testing and a universal asymptomatic testing programme. An online questionnaire was sent to all UoC students on 25 November to investigate risk factors for testing positive in the period after 30th October 2020. This asked about symptoms, SARS-CoV-2 test results, aspects of university life, and attendance at social events in the week prior to lockdown. Univariate and multivariable analyses were undertaken evaluating potential risk factors for SARS-CoV-2 positivity.Among 3980 students responding to the questionnaire, 99 (2.5%) reported testing SARS-CoV-2 positive in the period studied; 28 (28%) were asymptomatic. We found strong independent associations with SARS-CoV-2 positivity and attendance at two social settings in the City of Cambridge (adjusted odds ratio favouring disease 13.0 (95% CI 6.2-26.9) and 14.2 (95% CI 2.9-70)), with weaker evidence of association with three further social settings. By contrast, we did not observe strong independent associations between disease risk and accommodation type or attendance at a range of activities associated with the university curriculum.To conclude attendance at social settings can facilitate widespread SARS-CoV-2 transmission in university students. Constraint of transmission in higher education settings needs to emphasise risks outside university premises, as well as a COVID-safe environment within university premises.

Rapid implementation of SARS-CoV-2 sequencing to investigate cases of health-care associated COVID-19: a prospective genomic surveillance study.

BACKGROUND: The burden and influence of health-care associated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is unknown. We aimed to examine the use of rapid SARS-CoV-2 sequencing combined with detailed epidemiological analysis to investigate health-care associated SARS-CoV-2 infections and inform infection control measures. METHODS: In this prospective surveillance study, we set up rapid SARS-CoV-2 nanopore sequencing from PCR-positive diagnostic samples collected from our hospital (Cambridge, UK) and a random selection from hospitals in the East of England, enabling sample-to-sequence in less than 24 h. We established a weekly review and reporting system with integration of genomic and epidemiological data to investigate suspected health-care associated COVID-19 cases. FINDINGS: Between March 13 and April 24, 2020, we collected clinical data and samples from 5613 patients with COVID-19 from across the East of England. We sequenced 1000 samples producing 747 high-quality genomes. We combined epidemiological and genomic analysis of the 299 patients from our hospital and identified 35 clusters of identical viruses involving 159 patients. 92 (58%) of 159 patients had strong epidemiological links and 32 (20%) patients had plausible epidemiological links. These results were fed back to clinical, infection control, and hospital management teams, leading to infection-control interventions and informing patient safety reporting. INTERPRETATION: We established real-time genomic surveillance of SARS-CoV-2 in a UK hospital and showed the benefit of combined genomic and epidemiological analysis for the investigation of health-care associated COVID-19. This approach enabled us to detect cryptic transmission events and identify opportunities to target infection-control interventions to further reduce health-care associated infections. Our findings have important implications for national public health policy as they enable rapid tracking and investigation of infections in hospital and community settings. FUNDING: COVID-19 Genomics UK funded by the Department of Health and Social Care, UK Research and Innovation, and the Wellcome Sanger Institute.

Influenza-associated mortality in hospital care: a retrospective cohort study of risk factors and impact of oseltamivir in an English teaching hospital, 2016 to 2017.

BackgroundEvidence of an oseltamivir treatment effect on influenza A(H3N2) virus infections in hospitalised patients is incomplete.AimsThis cohort study aimed to evaluate risk factors for death among PCR-confirmed hospitalised cases of seasonal influenza A(H3N2) of all ages and the impact of oseltamivir.MethodsParticipants included all 332 PCR-confirmed influenza A(H3N2) cases diagnosed between 30 August 2016 and 17 March 2017 in an English university teaching Hospital. Oseltamivir treatment effect on odds of inpatient death was assessed by backward stepwise multivariable logistic regression analysis.ResultsThe odds of death were reduced by two thirds (odds ratio (OR): 0.32; 95% confidence interval (CI): 0.11-0.93), in inpatients treated with a standard course of oseltamivir 75 mg two times daily for 5 days - compared with those untreated with oseltamivir, after adjustment for age, sex, current excess alcohol intake, receipt of 2016/17 seasonal influenza vaccine, serum haemoglobin and hospital vs community attribution of acquisition of influenza.ConclusionsOseltamivir treatment given according to National Institutes of Clinical Excellence (NICE); United States Centres for Disease Control and Prevention (CDC); Infectious Diseases Society of America (IDSA) and World Health Organization (WHO) guidelines was shown to be effective in reducing the odds of mortality in inpatients with PCR-confirmed seasonal influenza A(H3N2) after adjustment in a busy routine English hospital setting. Our results highlight the importance of hospitals complying with relevant guidelines for prompt seasonal influenza PCR testing and ensuring standard oseltamivir treatment to all PCR-confirmed cases of seasonal influenza.

Risk factors for late HIV diagnosis in the East of England: evidence from national surveillance data and policy implications.

In 2014, 42% of all HIV diagnoses in the East of England were diagnosed late. Individuals unaware of their HIV status will not benefit from lifesaving and infectious-limiting antiretroviral therapy, and they remain at risk of decreased life expectancy and onward transmission of HIV. We sought to identify risk factors associated with late HIV diagnosis in the East of England to inform future HIV testing and prevention strategies relevant to the local population. Data on all HIV infected individuals aged ≥16 years and diagnosed between 2008 and 2014 in the East of England were obtained from the national HIV and AIDS Reporting System. Late diagnosis was defined as CD4 cell count below 350 cells/mm3 within 91 days of diagnosis. Logistic regression investigated risk factors for late HIV diagnosis. A total of 2469 people were included; 1342 (54%) were late HIV diagnoses. In multivariable analysis risk factors for late diagnosis were: age ≥30 years, originating from WHO regions of South-East Asia or Europe (excluding UK), heterosexual orientation and being diagnosed as an inpatient or by a general practitioner. The odds of late diagnosis significantly reduced every year (OR 0.95, 95% CI 0.90-0.99, p = 0.042). Despite this year-on-year reduction continued high rates suggest future HIV testing and prevention strategies should be informed by local regional epidemiology to allow those at greatest risk to be targeted appropriately.

Transmission of toxigenic Corynebacterium diphtheriae by a fully immunised resident returning from a visit to West Africa, United Kingdom, 2017.

In early 2017, a United Kingdom (UK)-born person in their 20s presented with a skin ulcer on the foot 3 weeks after returning from Ghana. The patient had last received a diphtheria-containing vaccine in 2013, completing the recommended course. MALDI-TOF of a cutaneous swab identified Corynebacterium diphtheriae. Real-time PCR ascertained the species and presence of the diphtheria toxin gene. An Elek test confirmed toxigenicity. The isolate was macrolide sensitive and penicillin resistant. The local Public Health England (PHE) Health Protection Team obtained the patient's clinical history and traced contacts to inform appropriate public health action. One close contact (in their early 80s with uncertain immunisation status who had not recently travelled) had a positive throat swab for toxigenic C. diphtheriae and reported a history of mild coryzal symptoms. Multilocus sequence typing revealed that strains from the index case and contact had Sequence Type 463. Diphtheria is extremely rare in the UK due to high vaccine coverage and this is the first documented transmission in 30 years. Clinicians and laboratory staff should remain highly suspicious of lesions in overseas travellers, even when patients are fully vaccinated. Older individuals who might not have completed a full immunisation course may have higher diphtheria susceptibility.

The English National Cohort Study of Flooding and Health: the change in the prevalence of psychological morbidity at year two.

BACKGROUND: The longer term impact of flooding on health is poorly understood. In 2015, following widespread flooding in the UK during winter 2013/14, Public Health England launched the English National Study of Flooding and Health. The study identified a higher prevalence of probable psychological morbidity one year after exposure to flooding. We now report findings after two years. METHODS: In year two (2016), a self-assessment questionnaire including flooding-related exposures and validated instruments to screen for probable anxiety, depression and post-traumatic stress disorder (PTSD) was sent to all participants who consented to further follow-up. Participants exposure status was categorised according to responses in year one; we assessed for exposure to new episodes of flooding and continuing flood-related problems in respondents homes. We calculated the prevalence and odds ratio for each outcome by exposure group relative to unaffected participants, adjusting for confounders. We used the McNemar test to assess change in outcomes between year one and year two. RESULTS: In year two, 1064 (70%) people responded. The prevalence of probable psychological morbidity remained elevated amongst flooded participants [n = 339] (depression 10.6%, anxiety 13.6%, PTSD 24.5%) and disrupted participants [n = 512] (depression 4.1%, anxiety 6.4%, PTSD 8.9%), although these rates were reduced compared to year one. A greater reduction in anxiety 7.6% (95% confidence interval [CI] 4.6-9.9) was seen than depression 3.8% (95% CI 1.5-6.1) and PTSD: 6.6% (95% CI 3.9-9.2). Exposure to flooding was associated with a higher odds of anxiety (adjusted odds ratio [aOR] 5.2 95%, 95% CI 1.7-16.3) and depression (aOR 8.7, 95% CI 1.9-39.8) but not PTSD. Exposure to disruption caused by flooding was not significantly associated with probable psychological morbidity. Persistent damage in the home as a consequence of the original flooding event was reported by 119 participants (14%). The odds of probable psychological morbidity amongst flooded participants who reported persistent damage, compared with those who were unaffected, were significantly higher than the same comparison amongst flooded participants who did not report persistent damage. CONCLUSIONS: This study shows a continuance of probable psychological morbidity at least two years following exposure to flooding. Commissioners and providers of health and social care services should be aware that the increased need in populations may be prolonged. Efforts to resolve persistent damage to homes may reduce the risk of probable psychological morbidity.

Unrecognised Outbreak: Human parainfluenza virus infections in a pediatric oncology unit. A new diagnostic PCR and virus monitoring system may allow early detection of future outbreaks.

Background: Human parainfluenza viruses (HPIVs) are significant causes of both upper and lower respiratory tract infections with type 3 (HPIV3) causing the most severe disease in the immunocompromised cohorts.  The objective of this study was to analyse the epidemiological nature of a cluster of cases of HPIV3 in a pediatric oncology unit of a major teaching hospital. Methods: In order to determine whether the activity observed represented a deviation from the norm, seasonal trends of HPIV3 in the surrounding geographical area as well as on the ward in question were analysed.  The genetic link between cases was established by the phylogenetic analysis of the non-coding hypervariable region between the M (Matrix) and F (fusion) genes of HPIV3. The 15 cases involved and 15 unrelated cases were sequenced.  Transmission routes were subsequently inferred and visualized using Konstanz Information Miner (KNIME) 3.3.2. Results: Of the 15 cases identified, 14 were attributed to a point source outbreak. Two out of 14 outbreak cases were found to differ by a single mutation A182C. The outbreak strain was also seen in 1 out of 15 unrelated cases, indicating that it was introduced from the community. Transmission modeling was not able to link all the cases and establish a conclusive chain of transmission. No staff were tested during the outbreak period. No deaths occurred as a result of the outbreak. Conclusion: A point source outbreak of HPIV3 was recognized post factum on an oncology pediatric unit in a major teaching hospital. This raised concern about the possibility of a future more serious outbreak. Weaknesses in existing systems were identified and a new dedicated respiratory virus monitoring system introduced.  Pediatric oncology units require sophisticated systems for early identification of potentially life-threatening viral outbreaks.

The English national cohort study of flooding and health: cross-sectional analysis of mental health outcomes at year one.

BACKGROUND: In winter 2013/14 there was widespread flooding in England. Previous studies have described an increased prevalence of psychological morbidity six months after flooding. Disruption to essential services may increase morbidity however there have been no studies examining whether those experiencing disruption but not directly flooded are affected. The National Study of Flooding and Health was established in order to investigate the longer-term impact of flooding and related disruptions on mental health and wellbeing. METHODS: In year one we conducted a cross sectional analysis of people living in neighbourhoods affected by flooding between 1 December 2013 and 31 March 2014. 8761 households were invited to participate. Participants were categorised according to exposure as flooded, disrupted by flooding or unaffected. We used validated instruments to screen for probable psychological morbidity, the Patient Health Questionnaire (PHQ 2), Generalised Anxiety Disorder scale (GAD-2) and Post Traumatic Stress Disorder (PTSD) checklist (PCL-6). We calculated prevalence and odds ratios for each outcome by exposure group relative to unaffected participants, adjusting for confounders. RESULTS: 2126 people (23%) responded. The prevalence of psychological morbidity was elevated amongst flooded participants ([n = 622] depression 20.1%, anxiety 28.3%, PTSD 36.2%) and disrupted participants ([n = 1099] depression 9.6%, anxiety 10.7% PTSD 15.2%). Flooding was associated with higher odds of all outcomes (adjusted odds ratios (aORs), 95% CIs for depression 5.91 (3.91-10.99), anxiety 6.50 (3.77-11.24), PTSD 7.19 (4.33-11.93)). Flooded participants who reported domestic utilities disruption had higher odds of all outcomes than other flooded participants, (aORs, depression 6.19 (3.30-11.59), anxiety 6.64 (3.84-11.48), PTSD 7.27 (4.39-12.03) aORs without such disruption, depression, 3.14 (1.17-8.39), anxiety 3.45 (1.45-8.22), PTSD 2.90 (1.25-6.73)). Increased floodwater depth was significantly associated with higher odds of each outcome. Disruption without flooding was associated with borderline higher odds of anxiety (aOR 1.61 (0.94-2.77)) and higher odds of PTSD 2.06 (1.27-3.35)) compared with unaffected participants. Disruption to health/social care and work/education was also associated with higher odds of psychological morbidity. CONCLUSIONS: This study provides an insight into the impact of flooding on mental health, suggesting that the impacts of flooding are large, prolonged and extend beyond just those whose homes are flooded.

Excess Mortality Attributable to Clostridium difficile and Risk Factors for Infection in an Historic Cohort of Hospitalised Patients Followed Up in the United Kingdom Death Register.

METHODS: We compared time from hospital admission to death in a probability sample of 100 Clostridium difficile infected cases and a probability sample of 98 non-cases admitted to an English teaching hospital between 2005 and 2007 with follow up in the UK national death register using survival analysis. RESULTS: Clostridium difficile infection was associated with a 50% increased risk of death (Hazard Ratio 1.51 (95% CI: 1.05-2.19 p = 0.03) at between five to eight years in Cox Regression analysis adjusting for age, sex, Charlson comorbidity index, diagnosis of a malignant condition and insertion of a nasogastric tube during admission. Acquisition of Clostridium difficile infection was independently associated with an almost six fold higher odds of being admitted with a diagnosis of infection of any other type (OR 5.79 (2.19, 15.25) p<0.001). CONCLUSIONS: Our results strongly support continued priority being given to improve prevention and treatment of Clostridium difficile infection in the English National Health Service particularly in patients admitted with an infection. Our results may be applicable to other health systems.

An Outbreak of Cryptosporidium parvum across England & Scotland Associated with Consumption of Fresh Pre-Cut Salad Leaves, May 2012.

BACKGROUND: We report a widespread foodborne outbreak of Cryptosporidium parvum in England and Scotland in May 2012. Cases were more common in female adults, and had no history of foreign travel. Over 300 excess cases were identified during the period of the outbreak. Speciation and microbiological typing revealed the outbreak strain to be C. parvum gp60 subtype IIaA15G2R1. METHODS: Hypothesis generation questionnaires were administered and an unmatched case control study was undertaken to test the hypotheses raised. Cases and controls were interviewed by telephone. Controls were selected using sequential digit dialling. Information was gathered on demographics, foods consumed and retailers where foods were purchased. RESULTS: Seventy-four laboratory confirmed cases and 74 controls were included in analyses. Infection was found to be strongly associated with the consumption of pre-cut mixed salad leaves sold by a single retailer. This is the largest documented outbreak of cryptosporidiosis attributed to a food vehicle.

Outbreak of mumps in a school setting, United Kingdom, 2013.

Effective protection against mumps can be achieved through 2 doses of the measles-mumps-rubella (MMR) vaccine. However, outbreaks of mumps have recently been described among populations with high vaccination coverage, including 2 doses of MMR. Here we describe an outbreak at a school in the East of England, UK. The school was attended by 540 pupils aged 10-19 years and had 170 staff. In total, 28 cases of mumps (24 pupils and 4 staff) were identified during 10 January to 16 March 2013. Vaccination status was known in 25 of the cases, and among these 21 (84.0%) had a documented history of 2 doses of MMR while the remaining had a history of one dose (2/25 cases, 8.0%) or no doses (2/25, 8.0%) of MMR. An outbreak control team recommended that MMR vaccine should be offered to all pupils whose parents consented to it, regardless of previous vaccination status. Additional MMR vaccines were administered to 103 pupils, including 76 (73.8%) third doses of MMR. Offering an additional dose of MMR appeared to be acceptable to parents, and we found it feasible to administer the intervention in a timely manner with resources from the local Public Health Centre (Primary Care Trust). An additional dose of MMR to all individuals at risk can be considered as an acceptable control measure for mumps outbreaks in schools even if the vaccination coverage is high. However, further evidence on the effectiveness, acceptability, and safety of this intervention is needed.

Incidence and risk factors for drug intolerance and association with incomplete treatment for tuberculosis: analysis of national case registers for England, Wales and Northern Ireland, 2001-2010.

Anti-tuberculosis drug regimens are efficacious, but drug intolerance can be severe and may impact on treatment completion rates. The Enhanced Tuberculosis Surveillance (ETS) system is a case register of all new notifications of tuberculosis in England, Wales and Northern Ireland. We conducted a cohort study to estimate the incidence of, and risk factors for, drug intolerance reported through ETS between 2001 and 2010 and to assess its relationship with treatment non-completion. Reports of drug intolerance were found for 868/67,547 (1.28%) patients in the cohort, and important risk factors were female sex, older age, later case report year and white ethnicity. Drug intolerance was associated with an approximate fivefold increased odds of treatment non-completion (p<0.001). These results highlight the need for better-tolerated drug regimens and close case management of patients at risk of drug intolerance to improve treatment completion rates and contribute to more effective disease control.

Evaluation of community-based trichiasis surgery in Northwest Ethiopia.

BACKGROUND: Surgery to correct trachomatous trichiasis (TT) is recommended to prevent blindness caused by trachoma. This study evaluated the outcomes of community-based trichiasis surgery with absorbable sutures, conducted in Amhara Regional State, Ethiopia. METHODS: A simple random sample of 431 patients was selected from surgical campaign records of which 363 (84.2%) were traced and enrolled into the study. Participants were interviewed and examined for trichiasis recurrence, complications of TT surgery and corneal opacity. Multilevel logistic regression models were used to explore the associations between trichiasis recurrence, corneal opacity and explanatory variables at the eye level. RESULTS: The prevalence of trichiasis recurrence was 9.4% (95% Confidence Interval [CI] 6.6-12.8) and corneal opacity was found in 14.3% (95% CI 10.9-18.3) of the study participants. The proportion of participants with complications of TT surgery was: granuloma 0.6% (95% CI 0.1-2.0); lid closure defects 5.5% (95% CI 3.4-8.4) and lid notching 16.8% (95% CI 13.1-21.1). No factors were identified for trichiasis recurrence. Corneal opacity was associated with increased age (Ptrend=0.001), more than 12 months post surgery (OR=2.7; 95%CI 1.3-5.6), trichiasis surgery complications (OR=2.9; 95%CI 1.4-5.9) and trichiasis recurrence (OR=2.5; 95%CI 1.0-6.3). CONCLUSION: Prevalence of recurrent trichiasis and granuloma were lower than expected but higher for lid closure defects and lid notching. The majority of the participants reported satisfaction with the trichiasis surgery they had undergone. The findings suggest that recurrence of trichiasis impacts on the patients' risk of developing corneal opacity but longitudinal studies are required to confirm this.

Whole-genome sequencing to identify transmission of Mycobacterium abscessus between patients with cystic fibrosis: a retrospective cohort study.

BACKGROUND: Increasing numbers of individuals with cystic fibrosis are becoming infected with the multidrug-resistant non-tuberculous mycobacterium (NTM) Mycobacterium abscessus, which causes progressive lung damage and is extremely challenging to treat. How this organism is acquired is not currently known, but there is growing concern that person-to-person transmission could occur. We aimed to define the mechanisms of acquisition of M abscessus in individuals with cystic fibrosis. METHOD: Whole genome sequencing and antimicrobial susceptibility testing were done on 168 consecutive isolates of M abscessus from 31 patients attending an adult cystic fibrosis centre in the UK between 2007 and 2011. In parallel, we undertook detailed environmental testing for NTM and defined potential opportunities for transmission between patients both in and out of hospital using epidemiological data and social network analysis. FINDINGS: Phylogenetic analysis revealed two clustered outbreaks of near-identical isolates of the M abscessus subspecies massiliense (from 11 patients), differing by less than ten base pairs. This variation represents less diversity than that seen within isolates from a single individual, strongly indicating between-patient transmission. All patients within these clusters had numerous opportunities for within-hospital transmission from other individuals, while comprehensive environmental sampling, initiated during the outbreak, failed to detect any potential point source of NTM infection. The clusters of M abscessus subspecies massiliense showed evidence of transmission of mutations acquired during infection of an individual to other patients. Thus, isolates with constitutive resistance to amikacin and clarithromycin were isolated from several individuals never previously exposed to long-term macrolides or aminoglycosides, further indicating cross-infection. INTERPRETATION: Whole genome sequencing has revealed frequent transmission of multidrug resistant NTM between patients with cystic fibrosis despite conventional cross-infection measures. Although the exact transmission route is yet to be established, our epidemiological analysis suggests that it could be indirect. FUNDING: The Wellcome Trust, Papworth Hospital, NIHR Cambridge Biomedical Research Centre, UK Health Protection Agency, Medical Research Council, and the UKCRC Translational Infection Research Initiative.

The association between time spent outdoors and myopia in children and adolescents: a systematic review and meta-analysis.

OBJECTIVE: To summarize relevant evidence investigating the association between time spent outdoors and myopia in children and adolescents (up to 20 years). DESIGN: Systematic review and meta-analysis. PARTICIPANTS: Results from 7 cross-sectional studies were pooled in a meta-analysis. A further 16 studies (8 cross-sectional not meeting criteria for meta-analysis; 7 prospective cohort studies; 1 randomized, controlled trial [RCT]) were reported in the systematic review. METHODS: The literature search included 4 databases (Medline, Embase, Web of Science, and Cochrane Central Register of Controlled Trials [CENTRAL]), and reference lists of retrieved studies. Estimates of association were pooled using random effects meta-analysis. We summarized data examining the association between time spent outdoors and prevalent myopia, incident myopia, and myopic progression. MAIN OUTCOME MEASURES: Pooled odds ratios (ORs) and 95% confidence intervals (CIs) for myopia for each additional hour spent outdoors per week from a meta-analysis. RESULTS: The pooled OR for myopia indicated a 2% reduced odds of myopia per additional hour of time spent outdoors per week, after adjustment for covariates (OR, 0.981; 95% CI, 0.973-0.990; P<0.001; I(2), 44.3%). This is equivalent to an OR of 0.87 for an additional hour of time spent outdoors each day. Three prospective cohort studies provided estimates of risk of incident myopia according to time spent outdoors, adjusted for possible confounders, although estimates could not be pooled, and the quality of studies and length of follow-up times varied. Three studies (2 prospective cohort and 1 RCT) investigated time spent outdoors and myopic progression and found increasing time spent outdoors significantly reduced myopic progression. CONCLUSIONS: The overall findings indicate that increasing time spent outdoors may be a simple strategy by which to reduce the risk of developing myopia and its progression in children and adolescents. Therefore, further RCTs are warranted to investigate the efficacy of increasing time outdoors as a possible intervention to prevent myopia and its progression.

Epidemiology of vitamin A deficiency and xerophthalmia in at-risk populations.

Vitamin A deficiency (VAD) is an important public health problem worldwide that contributes significantly to the global burden of disease. Vitamin A deficiency disorders include xerophthalmia and increased risk of infectious diseases, both of which increase risk of mortality. Xerophthalmia is also a leading cause of preventable blindness. Areas with highly prevalent VAD often share common dietary and other environmental exposures, including poverty, infectious diseases, limited development and poor availability of vitamin A containing food. Globally, the prevalence of VAD has been declining, which may be due to widespread vitamin A supplementation in conjunction with measles immunisation in at-risk populations. Recent meta-analyses confirm that provision of vitamin A to children aged between 6 months and 5 years confers a significant mortality benefit. Further preventative measures for VAD comprise improving availability of vitamin A containing food, including foods biofortified with vitamin A. Ensuring vitamin A is available in any form in adequate quantities remains problematic, especially in areas affected by environmental catastrophes and conflict, and other areas where access to vitamin A containing foods and healthcare interventions is limited. Hence, it remains essential that maternal and child health workers remain vigilant for VAD in nutritionally vulnerable populations.

Trachoma survey methods: a literature review.

Reliable population-based prevalence data are essential for planning, monitoring and evaluating trachoma control programmes and understanding the scale of the problem, yet they are not currently available for 22 out of 56 trachoma-endemic countries. Three survey methods have been advocated for trachoma: cluster random sampling (CRS); trachoma rapid assessment (TRA); and acceptance sampling trachoma rapid assessment (ASTRA). Our review highlights the benefits of CRS being simple, efficient, repeatable and giving population-based prevalence estimates of all signs of trachoma. There are limitations to TRA, which include: non-representative sampling; does not estimate prevalence; and lacks consistency and accuracy. ASTRA advocates small sample sizes but it is relatively complex, may result in imprecise prevalence estimates and does not estimate cicatricial signs of trachoma. We conclude that CRS should therefore remain the 'gold' standard for trachoma surveys. However, among the CRS surveys reviewed, we also found several methodological deficiencies of sample-size calculations, standardization of trachoma graders, reporting of confidence intervals of prevalence estimates, variability of age groups for presentation of age-specific prevalence, and lack of estimation of district prevalence estimates. Properly conducted surveys will be crucial if the objective of global elimination of blinding trachoma is to be charted and realized. Harmonization of survey methods will enhance the conduct and comparability of trachoma surveys needed for reliable mapping of prevalence within endemic countries. Consistent with WHO recommendations, we advocate for continued use of CRS as the survey design of choice for trachoma control programmes and propose ways of improving future surveys based on this method.

What will happen if we do nothing to control trachoma: health expectancies for blinding trachoma in southern Sudan.

BACKGROUND: Uncontrolled trachoma is a leading cause of blindness. Current global trachoma burden summary measures are presented as disability adjusted life years but have limitations due to inconsistent methods and inadequate population-based data on trachomatous low vision and blindness. We aimed to describe more completely the burden of blinding trachoma in Southern Sudan using health expectancies. METHODOLOGY/PRINCIPAL FINDINGS: Age and gender specific trachomatous trichiasis (TT) prevalence was estimated from 11 districts in Southern Sudan. The distribution of visual acuity (VA) in persons with TT was recorded in one district. Sudan life tables, TT prevalence, and VA were used to calculate Trichiasis Free Life Expectancy (TTFLE) and Trichiasis Life Expectancy (TTLE) using the Sullivan method. TTLE was broken down by VA to derive TTLE with normal vision, TTLE with low vision, and TTLE with blindness. Total life expectancy at birth in 2001 was 54.2 years for males and 58.1 for females. From our Sullivan models, trichiasis life expectancy at the age of 5 years was estimated to be 7.0 (95% confidence interval [CI] = 6.2-7.8) years (12% [95% CI = 11-14] of remaining life) for males and 10.9 (95% CI = 9.9-11.9 ) years (18% [95% CI = 16-20] of remaining life) for females. Trichiasis life expectancy with low vision or blindness was 5.1 (95% CI = 3.9-6.4) years (9% [95% CI = 7-11] of remaining life) and 7.6 (95% CI = 6.0-9.1) years (12% [95% CI = 10-15] of remaining life) for males and females, respectively. Women were predicted to live longer and spend a greater proportion of their lives with disabling trichiasis, low vision, and blindness compared to men. CONCLUSIONS: The study shows the future burden associated with doing nothing to control trachoma in Southern Sudan, that is, a substantial proportion of remaining life expectancy spent with trichiasis and low vision or blindness for both men and women, with a disproportionate burden falling on women.