Contact tracing indicators for COVID-19: Rapid scoping review and conceptual framework.

BACKGROUND: Contact tracing is one of the key interventions in response to the COVID-19 pandemic but its implementation varies widely across countries. There is little guidance on how to monitor contact tracing performance, and no systematic overview of indicators to assess contact tracing systems or conceptual framework for such indicators exists to date. METHODS: We conducted a rapid scoping review using a systematic literature search strategy in the peer-reviewed and grey literature as well as open source online documents. We developed a conceptual framework to map indicators by type (input, process, output, outcome, impact) and thematic area (human resources, financial resources, case investigation, contact identification, contact testing, contact follow up, case isolation, contact quarantine, transmission chain interruption, incidence reduction). RESULTS: We identified a total of 153 contact tracing indicators from 1,555 peer-reviewed studies, 894 studies from grey literature sources, and 15 sources from internet searches. Two-thirds of indicators were process indicators (102; 67%), while 48 (31%) indicators were output indicators. Only three (2%) indicators were input indicators. Indicators covered seven out of ten conceptualized thematic areas, with more than half being related to either case investigation (37; 24%) or contact identification (44; 29%). There were no indicators for the input area "financial resources", the outcome area "transmission chain interruption", and the impact area "incidence reduction". CONCLUSIONS: Almost all identified indicators were either process or output indicators focusing on case investigation, contact identification, case isolation or contact quarantine. We identified important gaps in input, outcome and impact indicators, which constrains evidence-based assessment of contact tracing systems. A universally agreed set of indicators is needed to allow for cross-system comparisons and to improve the performance of contact tracing systems.

Epidemiological, clinical, and public health response characteristics of a large outbreak of diphtheria among the Rohingya population in Cox's Bazar, Bangladesh, 2017 to 2019: A retrospective study.

BACKGROUND: Unrest in Myanmar in August 2017 resulted in the movement of over 700,000 Rohingya refugees to overcrowded camps in Cox's Bazar, Bangladesh. A large outbreak of diphtheria subsequently began in this population. METHODS AND FINDINGS: Data were collected during mass vaccination campaigns (MVCs), contact tracing activities, and from 9 Diphtheria Treatment Centers (DTCs) operated by national and international organizations. These data were used to describe the epidemiological and clinical features and the control measures to prevent transmission, during the first 2 years of the outbreak. Between November 10, 2017 and November 9, 2019, 7,064 cases were reported: 285 (4.0%) laboratory-confirmed, 3,610 (51.1%) probable, and 3,169 (44.9%) suspected cases. The crude attack rate was 51.5 cases per 10,000 person-years, and epidemic doubling time was 4.4 days (95% confidence interval [CI] 4.2-4.7) during the exponential growth phase. The median age was 10 years (range 0-85), and 3,126 (44.3%) were male. The typical symptoms were sore throat (93.5%), fever (86.0%), pseudomembrane (34.7%), and gross cervical lymphadenopathy (GCL; 30.6%). Diphtheria antitoxin (DAT) was administered to 1,062 (89.0%) out of 1,193 eligible patients, with adverse reactions following among 229 (21.6%). There were 45 deaths (case fatality ratio [CFR] 0.6%). Household contacts for 5,702 (80.7%) of 7,064 cases were successfully traced. A total of 41,452 contacts were identified, of whom 40,364 (97.4%) consented to begin chemoprophylaxis; adherence was 55.0% (N = 22,218) at 3-day follow-up. Unvaccinated household contacts were vaccinated with 3 doses (with 4-week interval), while a booster dose was administered if the primary vaccination schedule had been completed. The proportion of contacts vaccinated was 64.7% overall. Three MVC rounds were conducted, with administrative coverage varying between 88.5% and 110.4%. Pentavalent vaccine was administered to those aged 6 weeks to 6 years, while tetanus and diphtheria (Td) vaccine was administered to those aged 7 years and older. Lack of adequate diagnostic capacity to confirm cases was the main limitation, with a majority of cases unconfirmed and the proportion of true diphtheria cases unknown. CONCLUSIONS: To our knowledge, this is the largest reported diphtheria outbreak in refugee settings. We observed that high population density, poor living conditions, and fast growth rate were associated with explosive expansion of the outbreak during the initial exponential growth phase. Three rounds of mass vaccinations targeting those aged 6 weeks to 14 years were associated with only modestly reduced transmission, and additional public health measures were necessary to end the outbreak. This outbreak has a long-lasting tail, with Rt oscillating at around 1 for an extended period. An adequate global DAT stockpile needs to be maintained. All populations must have access to health services and routine vaccination, and this access must be maintained during humanitarian crises.

A One-Health Quantitative Model to Assess the Risk of Antibiotic Resistance Acquisition in Asian Populations: Impact of Exposure Through Food, Water, Livestock and Humans.

Antimicrobial resistance (AMR) has become a major threat worldwide, especially in countries with inadequate sanitation and low antibiotic regulation. However, adequately prioritizing AMR interventions in such settings requires a quantification of the relative impacts of environmental, animal, and human sources in a One-Health perspective. Here, we propose a stochastic quantitative risk assessment model for the different components at interplay in AMR selection and spread. The model computes the incidence of AMR colonization in humans from five different sources: water or food consumption, contacts with livestock, and interhuman contacts in hospitals or the community, and combines these incidences into a per-year acquisition risk. Using data from the literature and Monte-Carlo simulations, we apply the model to hypothetical Asian-like settings, focusing on resistant bacteria that may cause infections in humans. In both scenarios A, illustrative of low-income countries, and B, illustrative of high-income countries, the overall individual risk of becoming colonized with resistant bacteria at least once per year is high. However, the average predicted incidence of colonization was lower in scenario B at 0.82 (CrI [0.13, 5.1]) acquisitions/person/year, versus 1.69 (CrI [0.66, 11.13]) acquisitions/person/year for scenario A. A high percentage of population with no access to improved water on premises and a high percentage of population involved in husbandry are shown to strongly increase the AMR acquisition risk. The One-Health AMR risk assessment framework we developed may prove useful to policymakers throughout Asia, as it can easily be parameterized to realistically reproduce conditions in a given country, provided data are available.

Monitoring COVID-19 where capacity for testing is limited: use of a three-step analysis based on test positivity ratio.

In an effort to monitor coronavirus disease 2019 (COVID-19), many countries have been calculating the ratio of cases confirmed to tests performed (test positivity ratio - TPR). While inferior to sentinel surveillance, TPR has the benefit of being easily calculated using readily available data; however, interpreting TPR and its trends can be complex because both the numerator and the denominator are constantly changing. We describe a three-step process where the ratio of relative increase in cases to relative increase in tests is accounted for in an adjusted TPR. This adjusted value more appropriately reflects the case number and factors out the effect of changes in the number of tests done. Unadjusted and adjusted TPRs are then assessed step-wise with reference to the epidemic curve and the cumulative numbers of cases and tests. Use of this three-step analysis and its potential use in guiding public health interventions are demonstrated for selected countries and subnational areas of the World Health Organization South-East Asia Region, together with the Republic of Korea as a reference. To date, application of the three-step analysis to data from countries of the region has signalled potential inadequacies of testing strategies. Further work is needed on approaches to support countries where testing capacity is likely to remain constrained. One example would be enumeration of the average number of tests needed to detect one COVID-19 case, which could be stratified by factors such as location and population. Such data would allow evidence-informed strategies that best balance the highest detection rate with the prevailing testing capacity.

Impact of vaccines on antimicrobial resistance.

DRIVERS OF ANTIMICROBIAL RESISTANCE: Antibiotic use drives the development and spread of resistant bacterial infections. Antimicrobial resistance (AMR) has become a prolific global issue, due to significant increases in antibiotic use in humans, livestock and agriculture, inappropriate use (under-dosing and over-prescribing), and misuse of antibiotics (for viral infections where they are ineffective). Fewer new antibiotics are being developed. THE PROBLEM OF AMR: AMR is now considered a key threat to global health, leading to more mortality and increased healthcare costs threatening future conduct of routine medical procedures. Traditional approaches to address AMR include antibiotic stewardship, better hygiene/infection control, promoting antibiotic research and development, and restricting use for agricultural purposes. VACCINES AS A TOOL TO REDUCE AMR: While antibiotic development is declining, vaccine technology is growing. This review shows how vaccines can decrease AMR by preventing bacterial and viral infections, thereby reducing the use/misuse of antibiotics, and by preventing antibiotic-resistant infections. Vaccines are less likely to induce resistance. Some future uses and developments of vaccines are also discussed. CONCLUSIONS: Vaccines, along with other approaches, can help reduce AMR by preventing (resistant) infections and reducing antibiotic use. Industry and governments must focus on the development of novel vaccines and drugs against resistant infections to successfully reduce AMR. A graphical abstract is available online.

Community-acquired pneumonia and Gram-negative bacilli in Cambodia-incidence, risk factors and clinical characteristics.

Background: In Western settings, community-acquired pneumonia (CAP) due to Gram-negative bacilli (GNB) is relatively rare. Previous studies from Asia, however, indicate a higher prevalence of GNB in CAP, but data, particularly from Southeast Asia, are limited. Methods: This is a prospective observational study of 1451 patients ≥15 y of age with CAP from two hospitals in Cambodia between 2007 and 2010. The proportion of GNB was estimated. Risk factors and clinical characteristics of CAP due to GNB were assessed using logistic regression models. Results: The prevalence of GNB was 8.6% in all CAP patients and 15.8% among those with a valid respiratory sample. GNB infection was independently associated with diabetes, higher leucocyte count and CAP severity. Mortality was higher in patients with CAP due to GNB. Conclusions: We found a high proportion of GNB in a population hospitalized for CAP in Cambodia. Given the complex antimicrobial sensitivity patterns of certain GNBs and the rapid emergence of multidrug-resistant GNB, microbiological laboratory capacity should be strengthened and prospective clinical trials comparing empiric treatment algorithms according to the severity of CAP are needed.

Serotype Distribution of Clinical Streptococcus pneumoniae Isolates before the Introduction of the 13-Valent Pneumococcal Conjugate Vaccine in Cambodia.

Childhood vaccination with the 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in Cambodia in January 2015. Baseline data regarding circulating serotypes are scarce. All microbiology laboratories in Cambodia were contacted for identification of stored isolates of Streptococcus pneumoniae from clinical specimens taken before the introduction of PCV13. Available isolates were serotyped using a multiplex polymerase chain reaction method. Among 166 identified isolates available for serotyping from patients with pneumococcal disease, 4% were isolated from upper respiratory samples and 80% were from lower respiratory samples, and 16% were invasive isolates. PCV13 serotypes accounted for 60% (95% confidence interval [CI] 52-67) of all isolates; 56% (95% CI 48-64) of noninvasive and 77% (95% CI 57-89) of invasive isolates. Antibiotic resistance was more common among PCV13 serotypes. This study of clinical S. pneumoniae isolates supports the potential for high reduction in pneumococcal disease burden and may serve as baseline data for future monitoring of S. pneumoniae serotypes circulation after implementation of PCV13 childhood vaccination in Cambodia.

Systematic review of electronic surveillance of infectious diseases with emphasis on antimicrobial resistance surveillance in resource-limited settings.

BACKGROUND: Electronic surveillance of infectious diseases involves rapidly collecting, collating, and analyzing vast amounts of data from interrelated multiple databases. Although many developed countries have invested in electronic surveillance for infectious diseases, the system still presents a challenge for resource-limited health care settings. METHODS: We conducted a systematic review by performing a comprehensive literature search on MEDLINE (January 2000-December 2015) to identify studies relevant to electronic surveillance of infectious diseases. Study characteristics and results were extracted and systematically reviewed by 3 infectious disease physicians. RESULTS: A total of 110 studies were included. Most surveillance systems were developed and implemented in high-income countries; less than one-quarter were conducted in low-or middle-income countries. Information technologies can be used to facilitate the process of obtaining laboratory, clinical, and pharmacologic data for the surveillance of infectious diseases, including antimicrobial resistance (AMR) infections. These novel systems require greater resources; however, we found that using electronic surveillance systems could result in shorter times to detect targeted infectious diseases and improvement of data collection. CONCLUSIONS: This study highlights a lack of resources in areas where an effective, rapid surveillance system is most needed. The availability of information technology for the electronic surveillance of infectious diseases, including AMR infections, will facilitate the prevention and containment of such emerging infectious diseases.

Seroprevalence and Transmission of Human Influenza A(H5N1) Virus before and after Virus Reassortment, Cambodia, 2006-2014.

Thirty-five human influenza A(H5N1) cases were reported in Cambodia during 2013-2014 after emergence of a clade 1.1.2 reassortant virus. We tested 881 villagers and found 2 cases of pauci- or asymptomatic infection. Seroprevalence after emergence of the reassortant strain (0.2%) was lower than the aggregate seroprevalence of 1.3% reported in earlier studies.

Assessment of Ebola virus disease preparedness in the WHO South-East Asia Region.

OBJECTIVE: To conduct assessments of Ebola virus disease preparedness in countries of the World Health Organization (WHO) South-East Asia Region. METHODS: Nine of 11 countries in the region agreed to be assessed. During February to November 2015 a joint team from WHO and ministries of health conducted 4-5 day missions to Bangladesh, Bhutan, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand and Timor-Leste. We collected information through guided discussions with senior technical leaders and visits to hospitals, laboratories and airports. We assessed each country's Ebola virus disease preparedness on 41 tasks under nine key components adapted from the WHO Ebola preparedness checklist of January 2015. FINDINGS: Political commitment to Ebola preparedness was high in all countries. Planning was most advanced for components that had been previously planned or tested for influenza pandemics: multilevel and multisectoral coordination; multidisciplinary rapid response teams; public communication and social mobilization; drills in international airports; and training on personal protective equipment. Major vulnerabilities included inadequate risk assessment and risk communication; gaps in data management and analysis for event surveillance; and limited capacity in molecular diagnostic techniques. Many countries had limited planning for a surge of Ebola cases. Other tasks needing improvement included: advice to inbound travellers; adequate isolation rooms; appropriate infection control practices; triage systems in hospitals; laboratory diagnostic capacity; contact tracing; and danger pay to staff to ensure continuity of care. CONCLUSION: Joint assessment and feedback about the functionality of Ebola virus preparedness systems help countries strengthen their core capacities to meet the International Health Regulations.

Environmental contamination and risk factors for transmission of highly pathogenic avian influenza A(H5N1) to humans, Cambodia, 2006-2010.

BACKGROUND: Highly pathogenic avian influenza A (H5N1) virus has been of public health concern since 2003. Probable risk factors for A(H5N1) transmission to human have been demonstrated in several studies or epidemiological reports. However, transmission patterns may differ according to demographic characteristics of the population and local practices. This article aggregates these data from three studies with data collected in the previous surveys in 2006 and 2007 to further examine the risks factors associated with presence of anti-A(H5) antibodies among villagers residing within outbreak areas. METHODS: We aggregated 5-year data (2006-2010) from serology survey and matched case-control studies in Cambodia to further examine the risks factors associated with A(H5N1) infection among villagers in the outbreak areas. RESULTS: Serotesting among villagers detected 35 (1.5 % [0-2.6]) positive cases suggesting recent exposure to A(H5N1) virus. Practices associated with A(H5N1) infection among all ages were: having poultry cage or nesting area under or adjacent to the house (OR: 6.7 [1.6-28.3]; p = 0.010) and transporting poultry to market (OR: 17.6 [1.6-193.7]; p = 0.019). Practices found as risk factors for the infection among age under 20 years were swimming/bathing in ponds also accessed by domestic poultry (OR: 4.6 [1.1-19.1]; p = 0.038). Association with consuming wild birds reached borderline significance (p = 0.066). CONCLUSION: Our results suggest that swimming/bathing in contaminated pond water and close contact with poultry may present a risk of A(H5N1) transmission to human.

Human Rabies in China, 1960-2014: A Descriptive Epidemiological Study.

BACKGROUND: Rabies in China remains a public health problem. In 2014, nearly one thousand rabies-related deaths were reported while rabies geographic distribution has expanded for the recent years. This report used surveillance data to describe the epidemiological characteristics of human rabies in China including determining high-risk areas and seasonality to support national rabies prevention and control activities. METHODS: We analyzed the incidence and distribution of human rabies cases in mainland China using notifiable surveillance data from 1960-2014, which includes a detailed analysis of the recent years from 2004 to 2014. RESULTS: From 1960 to 2014, 120,913 human rabies cases were reported in mainland China. The highest number was recorded in 1981(0.7/100,000; 7037 cases), and in 2007(0.3/100,000; 3300 cases). A clear seasonal pattern has been observed with a peak in August (11.0% of total cases), Human rabies cases were reported in all provinces with a yearly average of 2198 from 1960 to 2014 in China, while the east and south regions were more seriously affected compared with other regions. From2004 to 2014, although the number of cases decreased by 65.2% since 2004 from 2651 to 924 cases, reported areas has paradoxically expanded from 162 prefectures to 200 prefectures and from southern to the central and northern provinces of China. Farmers accounted most of the cases (65.0%); 50-59 age group accounted for the highest proportion (20.5%), and cases are predominantly males with a male-to-female ratio of 2.4:1 on average. CONCLUSIONS: Despite the overall steady decline of cases since the peak in 2007, the occurrence of cases in new areas and the spread trend were obvious in China in recent years. Further investigations and efforts are warranted in the areas have high rabies incidence to control rabies by interrupting transmission from dogs to humans and in the dog population. Furthermore, elimination of rabies should be eventually the ultimate goal for China.