Evaluation of Less Invasive Sampling Tools for the Diagnosis of Cutaneous Leishmaniasis.

Background: Diagnosis of cutaneous leishmaniasis (CL) usually relies on invasive samples, but it is unclear whether more patient-friendly tools are good alternatives for diverse lesions when used with polymerase chain reaction (PCR). Methods: Patients with suspected CL were enrolled consecutively in a prospective diagnostic accuracy study. We compared dental broach, tape disc, and microbiopsy samples with PCR as index tests, using PCR with skin slit samples as reference test. Subsequently, we constructed a composite reference test including microscopy, the 3 index tests and skin slit PCR, and we compared these same tests with the composite reference test. We assessed diagnostic accuracy parameters with 95% confidence intervals for all comparisons. Results: Among 344 included patients, 282 (82.0%) had CL diagnosed, and 62 (18.0%) CL absence, by skin slit PCR. The sensitivity and specificity by PCR were 89.0% (95% confidence interval, 84.8%-92.1%) and 58.1% (45.7%-69.5%), respectively, for dental broach, 96.1% (93.2%-97.8%) and 27.4% (17.9%-39.6%) for tape disc, and 74.8% (66.3%-81.7%) and 72.7% (51.8%-86.8%) for microbiopsy. Several reference test-negative patients were consistently positive with the index tests. Using the composite reference test, dental broach, and skin slit had similar diagnostic performance. Discussion: Dental broach seems a less invasive but similarly accurate alternative to skin slit for diagnosing CL when using PCR. Tape discs lack specificity and seem unsuitable for CL diagnosis without cutoff. Reference tests for CL are problematic, since using a single reference test is likely to miss true cases, while composite reference tests are often biased and impractical as they require multiple tests.

Assessing the effects of SARS-CoV-2 vaccination on the risk of household transmission during delta variant circulation: a population-based data linkage cohort study.

Background: Data on SARS-CoV-2 vaccine effectiveness to reduce transmission of infection in household settings are limited. We examined the effects of SARS-CoV-2 vaccines on Delta variant transmission within households in an infection-naïve population. Methods: This was a population-based data linkage cohort study in the Greater Sydney Metropolitan Area, New South Wales, Australia based on cases observed in June-November 2021. In households with ≥1 confirmed COVID-19 case, we calculated adjusted odds ratios (aOR) and 95% Confidence Intervals (95% CI) for the risk of SARS-CoV-2 transmission, by vaccination status (unvaccinated, partially vaccinated, fully vaccinated, or waning) and type of vaccines (mRNA or vector-based) received by both index cases and household contacts. Findings: In 20,651 households with a single index case, 18,542 of 72,768 (25%) household contacts tested PCR-positive ≤14 days after their respective index case. Household contacts with partial, full, or waning mRNA vaccination had aORs of 0.46 (95% CI 0.40-0.52), 0.36 (95% CI 0.32-0.41) and 0.64 (95% CI 0.51-0.80) compared to unvaccinated contacts, while for vector vaccines the corresponding aORs were 0.77 (95% CI 0.67-0.89), 0.65 (95% CI 0.55-0.76), and 0.64 (95% CI 0.39-1.05). Full mRNA-vaccination in index cases compared to non-vaccination was associated with aORs between 0.09 and 0.21 depending on the vaccination status of household contacts. Interpretation: Full vaccination of household contacts reduced the odds to acquire infection with the SARS-CoV-2 Delta variant in household settings by two thirds for mRNA vaccines and by one third for vector vaccines. For index cases, being fully vaccinated with an mRNA vaccine reduced the odds of onwards transmission by four-fifths compared to unvaccinated index cases. Full vaccination offered stronger protection than partial vaccination, particularly for mRNA vaccines, but with reduced effects when the last vaccination preceded exposure by ≥3 months. Funding: New South Wales Ministry of Health.

Access to and utilization of COVID-19 antigen rapid diagnostic tests (Ag-RDTs) among people living with HIV (PLWH): A mixed methods study from Cambodia.

Several COVID-19 antigen rapid diagnostic tests have been approved in Cambodia, but no evidence exists about the access to and utilization of these tests. This limits public health interventions to increase testing, especially among vulnerable populations such as people living with HIV (PLWH). We conducted a mixed method study among PLWH in Phnom Penh, Cambodia, between July and August 2022 to understand their current Ag-RDT access and utilization levels, as well as key barriers and drivers. We undertook a cross-sectional survey and focus group discussions among 280 and 10 PLWH, respectively, from five HIV treatment centres using a probability-proportional-to-size and simple random sampling approach. Access was defined as having received a COVID-19 Ag-RDT within the six months and utilization as having administered a COVID-19 Ag-RDT, either to oneself or to others, within the 12 months prior to the study. We calculated means, standard deviations and proportions for continuous and categorical variables, using a linear regression model with random effects to account for clustering. Additionally, we fitted a logistic model with random effects to assess factors associated with Ag-RDT access. For the qualitative data, we used thematic analyses to identify barriers/enablers of Ag-RDT access and utilization. About 35% (n = 101) of PLWH reported having had access to an Ag-RDT test in the past six months. About 11% (n = 32) of the study participants administered the Ag-RDT to themselves, 4% (n = 10) to others and 9% (n = 24) have done both, in the past 12 months. Age and education appeared to be associated with Ag-RDT access in the logistic models. Price and advice from pharmacists were commonly reported to be the main selection criteria for the brand of Ag-RDT chosen. Ag-RDTs are an important diagnostic tool for COVID-19 among PLWH in Cambodia, but familiarity of use and price could hinder better uptake, access and utilization.

Chronic high level parasitemia in HIV-infected individuals with or without visceral leishmaniasis in an endemic area in North-West Ethiopia: potential superspreaders?

BACKGROUND: HIV patients with recurrent visceral leishmaniasis (VL) could potentially drive Leishmania transmission in areas with anthroponotic transmission such as East-Africa, but studies are lacking. Leishmania parasitemia has been used as proxy for infectiousness. METHODS: This study is nested within the PreLeish prospective cohort study, following a total of 490 HIV infected individuals free of VL at enrollment for upto 24-37 months in North-West Ethiopia. Blood Leishmania PCR was done systematically. This case series reports on ten HIV-coinfected individuals with chronic VL (≥3 VL episodes during follow-up) for upto 37 months, and three individuals with asymptomatic Leishmania infection for upto 24 months. RESULTS: All ten chronic VL cases were male, on antiretroviral treatment, with 0-11 relapses before enrollment. Median baseline CD4 counts were 82 cells/µL. They displayed three to six VL treatment episodes over a period upto 37 months. Leishmania blood PCR levels were strongly positive for almost the entire follow-up time (median Ct value 26 (IQR 23-30), including during periods between VL treatment. Additionally, we describe three HIV-infected individuals with asymptomatic Leishmania infection and without VL history, with equally strong Leishmania parasitemia over a period of upto 24 months without developing VL. All were on antiretroviral treatment at enrollment, with baseline CD4 counts ranging from 78 to 350 cells/µL. CONCLUSION: These are the first data on chronic parasitemia in HIV-infected individuals from L donovani endemic areas. HIV patients with asymptomatic and symptomatic Leishmania infection could potentially be highly infectious and constitute Leishmania superspreaders. Xenodiagnosis studies are required to confirm infectiousness.

Long-Term Progression-Free Survival of a Pre-Treated Patient with Metastatic Colorectal Cancer Receiving Trifluridine/Tipiracil.

Trifluridine/tipiracil is approved for the use in later or last-line setting in previously treated metastatic colorectal cancer (mCRC) patients who progressed on standard anti-tumor drugs including 5-fluorouracil (5-FU), irinotecan, oxaliplatin, anti-VEGF and anti-EGFR antibodies, or who are not considered candidates for those standard therapies. In this report, we describe a 67-year-old male patient with KRAS-mutated mCRC and metachronous liver and lung metastasis who failed prior 5-FU- and irinotecan-containing regimens, but then showed long-term disease control for 31 months on single-agent trifluridine/tipiracil given as second-line treatment. According to our experience, trifluridine/tipiracil is a feasible and effective treatment option in earlier but not necessarily last-line therapy in mCRC patients who are not considered candidates for doublet or triplet chemotherapy. Besides its efficacy, it is associated with maintained quality of life and a manageable toxicity profile. Considering increasing age of mCRC patients and their wish for maintaining an independent lifestyle, further research on the use of trifluridine/tipiracil in earlier lines of systemic mCRC therapy is warranted.

Breathing pattern disorder in chronic rhinosinusitis with severe asthma: nasal obstruction and polyps do not increase prevalence.

OBJECTIVES: Chronic rhinosinusitis (CRS) with severe asthma are associated with breathing pattern disorder (BPD). Mouth breathing is a sign of breathing pattern disorder, and nose breathing a fundamental part of breathing pattern retraining for BPD. The prevalence of BPD in relation to CRS subtypes and the relationship of nasal obstruction to BPD in CRS and associated severe asthma is unknown. The breathing pattern assessment tool (BPAT) can identify BPD. Our objective was to thus investigate the prevalence of BPD, nasal airflow obstruction and measures of airway disease severity in CRS with (CRSwNP) and without nasal polyps (CRSsNP) in severe asthma. METHODS: We determined whether CRS status, peak nasal inspiratory flow (PNIF) or polyp disease increased BPD prevalence. Demographic factors, measures of airway function and breathlessness in relation to BPD status and CRS subtypes were also evaluated. RESULTS: 130 Patients were evaluated (n = 69 had BPD). The prevalence of BPD in CRS with severe asthma was 53.1%. There was no difference between BPD occurrence between CRSwNP and CRSsNP. The mean polyp grade and PNIF were not statistically different between the BPD and non-BPD group. The presence of nasal polyps did not increase breathlessness. CONCLUSIONS: BPD and CRS are commonly co-associated. CRS status and nasal obstruction per se does not increase BPD prevalence.

How people with tinnitus-related insomnia experience group CBT-for-insomnia (CBTi): a thematic analysis.

Objective: Although insomnia often compounds tinnitus, sleeping problems in people experiencing tinnitus are rarely treated. This study investigates the experiences of participants receiving Cognitive Behavioural Therapy for insomnia (CBTi) as part of a randomised controlled trial for managing tinnitus-related insomnia. The aim of this study is to gain detailed insight into participants' perceptions and experiences of this treatment.Design: Semi-structured interviews were conducted via phone or in-person by one of the two clinical psychologists who facilitated the CBTi sessions. Reflexive thematic analysis with semantic inductive approach was used for analysis to keep the research question theoretically flexible.Study samples: Eight participants (three females, age range 32-69 years) were interviewed six months after CBTi completion.Results: Three superordinate themes were identified: "Common humanity and transcending individual distress," "Changing the things I can" and "Accepting the things I cannot change." The group environment helped participants to normalise their experiences. Reliable tinnitus/sleep information and robust behavioural change techniques helped participants to respond and relate to their condition differently.Conclusion: Generally, participants reported long-term benefits from CBTi to treat tinnitus-related insomnia, particularly increased confidence, and getting on with life. CBTi is multi-component, so clinicians need to respond to individual preferences and lifestyles.

After action review of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, in 2020.

Surveillance is the backbone of any response to an infectious disease outbreak, and comprehensive evaluation of surveillance systems is crucial. However, structured evaluations of surveillance systems during the COVID-19 pandemic are scarce. We conducted an after action review (AAR) of the performance of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, during 2020 using the COVID-19-specific AAR methodology developed by the World Health Organization in combination with guidance from the US Centers for Disease Control and Prevention (CDC). We conducted a stakeholder survey, document reviews, and key informant interviews with staff from Quang Ninh CDC's COVID-19 surveillance system. The COVID-19 surveillance system was based on the pre-existing surveillance system in the province. The system's strengths were early preparation for emergency response, strong governance and central coordination, and multidisciplinary collaboration. Stakeholders agreed that the system proved useful and adaptive to the fast-evolving COVID-19 situation but was weakened by overly complex systems, redundant administrative processes, unclear communication channels, and lack of resources. Overall, the surveillance systems in Quang Ninh province proved effective in containing COVID-19 and adaptive in a fast-changing epidemiological context. Several recommendations were made based on identified areas of concern that are of relevance for COVID-19 surveillance systems in Vietnam and similar settings.

Assessing the robustness of COVID-19 vaccine efficacy trials: systematic review and meta-analysis, January 2023.

BackgroundVaccines play a crucial role in the response to COVID-19 and their efficacy is thus of great importance.AimTo assess the robustness of COVID-19 vaccine efficacy (VE) trial results using the fragility index (FI) and fragility quotient (FQ) methodology.MethodsWe conducted a Cochrane and PRISMA-compliant systematic review and meta-analysis of COVID-19 VE trials published worldwide until 22 January 2023. We calculated the FI and FQ for all included studies and assessed their associations with selected trial characteristics using Wilcoxon rank sum tests and Kruskal-Wallis H tests. Spearman correlation coefficients and scatter plots were used to quantify the strength of correlation of FIs and FQs with trial characteristics.ResultsOf 6,032 screened records, we included 40 trials with 54 primary outcomes, comprising 909,404 participants with a median sample size per outcome of 13,993 (interquartile range (IQR): 8,534-25,519). The median FI and FQ was 62 (IQR: 22-123) and 0.50% (IQR: 0.24-0.92), respectively. FIs were positively associated with sample size (p < 0.001), and FQs were positively associated with type of blinding (p = 0.023). The Spearman correlation coefficient for FI with sample size was moderately strong (0.607), and weakly positive for FI and FQ with VE (0.138 and 0.161, respectively).ConclusionsThis was the largest study on trial robustness to date. Robustness of COVID-19 VE trials increased with sample size and varied considerably across several other important trial characteristics. The FI and FQ are valuable complementary parameters for the interpretation of trial results and should be reported alongside established trial outcome measures.

After action review of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, in 2020.

Surveillance is the backbone of any response to an infectious disease outbreak, and comprehensive evaluation of surveillance systems is crucial. However, structured evaluations of surveillance systems during the COVID-19 pandemic are scarce. We conducted a after action review (AAR) of the performance of the COVID-19 surveillance system in Quang Ninh Province, Vietnam, during 2020 using the COVID-19-specific AAR methodology developed by the World Health Organization in combination with guidance from the US Centers for Disease Control and Prevention (CDC). We conducted a stakeholder survey, document reviews, and key informant interviews with staff from Quang Ninh CDC's COVID-19 surveillance system. The COVID-19 surveillance system was based on the pre-existing surveillance system in the province. The system's strengths were early preparation for emergency response, strong governance and central coordination, and multidisciplinary collaboration. Stakeholders agreed that the system proved useful and adaptive to the fast-evolving COVID-19 situation but was weakened by overly complex systems, redundant administrative processes, unclear communication channels, and lack of resources. Overall, the surveillance systems in Quang Ninh province proved effective in containing COVID-19 and adaptive in a fast-changing epidemiological context. Several recommendations were made based on identified areas of concern that are of relevance for COVID-19 surveillance systems in Vietnam and similar settings.

Cognitive behavioural therapy for insomnia (CBTi) as a treatment for tinnitus-related insomnia: a randomised controlled trial.

Insomnia is a significant difficulty and is reported by large proportion of people with tinnitus. Although cognitive behavioural therapy for insomnia (CBTi) might be an effective treatment, no controlled studies had been conducted to date. This randomised controlled trial evaluated the benefits of CBTi on a sample of 102 people with tinnitus-related insomnia. Participants were randomised to 1) CBTi, 2) Audiology-Based Care (ABC) or 3) Sleep Support Group (SSG). Primary outcomes included insomnia, sleep efficiency and total sleep time. Secondary outcomes measured sleep onset latency, sleep quality, tinnitus distress, psychological distress, functioning and quality of life. CBTi was superior at reducing insomnia and increasing sleep efficiency compared to ABC post-intervention and at 6-month follow-up. ABC was superior at reducing insomnia and increasing sleep efficiency compared to SSG. Both CBTi and ABC reported increased total sleep time compared to SSG at 6-month follow. More than 80% of participants in the CBTi group reported clinically meaningful improvements compared to 47% in ABC and 20% for those receiving social support. CBTi was more effective in reducing tinnitus distress and improving sleep quality, functioning and some aspects of mental health. CBTi and ABC offer effective treatments for tinnitus-related sleep disorder but CBTi offers a sizeable benefit.

Long-lasting insecticidal nets provide protection against malaria for only a single year in Burundi, an African highland setting with marked malaria seasonality.

BACKGROUND: Long-lasting insecticidal nets (LLINs) are one of the key interventions in the global fight against malaria. Since 2014, mass distribution campaigns of LLINs aim for universal access by all citizens of Burundi. In this context, we assess the impact of LLINs mass distribution campaigns on malaria incidence, focusing on the endemic highland health districts. We also explored the possible correlation between observed trends in malaria incidence with any variations in climate conditions. METHODS: Malaria cases for 2011-2019 were obtained from the National Health Information System. We developed a generalised additive model based on a time series of routinely collected data with malaria incidence as the response variable and timing of LLIN distribution as an explanatory variable to investigate the duration and magnitude of the LLIN effect on malaria incidence. We added a seasonal and continuous-time component as further explanatory variables, and health district as a random effect to account for random natural variation in malaria cases between districts. RESULTS: Malaria transmission in Burundian highlands was clearly seasonal and increased non-linearly over the study period. Further, a fast and steep decline of malaria incidence was noted during the first year after mass LLIN distribution (p<0.0001). In years 2 and 3 after distribution, malaria cases started to rise again to levels higher than before the control intervention. CONCLUSION: This study highlights that LLINs did reduce the incidence in the first year after a mass distribution campaign, but in the context of Burundi, LLINs lost their impact after only 1 year.

Understanding the COVID-19 Infodemic: Analyzing User-Generated Online Information During a COVID-19 Outbreak in Vietnam.

OBJECTIVES: Online misinformation has reached unprecedented levels during the coronavirus disease 2019 (COVID-19) pandemic. This study analyzed the magnitude and sentiment dynamics of misinformation and unverified information about public health interventions during a COVID-19 outbreak in Da Nang, Vietnam, between July and September 2020. METHODS: We analyzed user-generated online information about five public health interventions during the Da Nang outbreak. We compared the volume, source, sentiment polarity, and engagements of online posts before, during, and after the outbreak using negative binomial and logistic regression, and assessed the content validity of the 500 most influential posts. RESULTS: Most of the 54,528 online posts included were generated during the outbreak (n = 46,035; 84.42%) and by online newspapers (n = 32,034; 58.75%). Among the 500 most influential posts, 316 (63.20%) contained genuine information, 10 (2.00%) contained misinformation, 152 (30.40%) were non-factual opinions, and 22 (4.40%) contained unverifiable information. All misinformation posts were made during the outbreak, mostly on social media, and were predominantly negative. Higher levels of engagement were observed for information that was unverifiable (incidence relative risk [IRR] = 2.83; 95% confidence interval [CI], 1.33-0.62), posted during the outbreak (before: IRR = 0.15; 95% CI, 0.07-0.35; after: IRR = 0.46; 95% CI, 0.34-0.63), and with negative sentiment (IRR = 1.84; 95% CI, 1.23-2.75). Negatively toned posts were more likely to be misinformation (odds ratio [OR] = 9.59; 95% CI, 1.20-76.70) or unverified (OR = 5.03; 95% CI, 1.66-15.24). CONCLUSIONS: Misinformation and unverified information during the outbreak showed clustering, with social media being particularly affected. This indepth assessment demonstrates the value of analyzing online "infodemics" to inform public health responses.

Investigating COVID-19 transmission in a tertiary hospital in Hanoi, Vietnam using social network analysis.

OBJECTIVES: In March 2020, a COVID-19 outbreak in a major referral hospital in Hanoi, Vietnam led to 7664 patients and staff being sent into lockdown for 2 weeks, and more than 52,200 persons across 49 provinces being quarantined. We assessed SARS-CoV-2 transmission patterns during this to-date largest hospital outbreak in Vietnam using social network analysis (SNA). METHODS: We constructed a directed relational network and calculated network metrics for 'degree', 'betweenness', 'closeness' and 'eigenvector' centrality to understand individual-level transmission patterns. We analysed network components and modularity to identify sub-network structures with disproportionately big effects. RESULTS: We detected 68 connections between 46 confirmed cases, of whom 27 (58.7%) were ancillary support staff, 7 (15.2%) caregivers, 6 (13%) patients and 2 (4.4%) nurses. Among the 10 most important cases selected by each SNA network metric, transmission dynamics clustered in 17 cases, of whom 12 (70.6%) cases were ancillary support staff. Ancillary support staff also constituted 71.1% of cases in the dominant sub-network and 68.8% of cases in the three largest sub-communities. CONCLUSIONS: We identified non-clinical ancillary support staff, who are responsible for room service and food distribution in hospital wards in Vietnam, as a group with disproportionally big impacts on transmission dynamics during this outbreak. Our findings call for a holistic approach to nosocomial outbreak prevention and response that includes both clinical and non-clinical hospital staff. Our work also shows the potential of SNA as a complementary outbreak investigation method to better understand infection patterns in hospitals and similar settings.

Assessing the mental effects of COVID-19-related work on depression among community health workers in Vietnam.

BACKGROUND: Community health workers (CHWs) involved in the COVID-19 response might be at increased risk of developing depression, though evidence is scarce. We investigated effects of COVID-19-related work on changes in depression levels among CHWs in Vietnam and identified sub-groups among CHWs who are at particular risk of developing severe depression. METHODS: We conducted a cross-sectional online survey among 979 CHWs who were involved in the COVID-19 response in Vietnam, in particular during the 2021 Tet holiday outbreak between January and March 2021. Respondents were asked to report depression symptoms at two-time points, before the start of the COVID-19 pandemic (average June to December 2019) and during the 2021 Tet holiday outbreak using the PHQ-9 mental health questionnaire. We estimated depression levels at both time points and developed univariate and multivariable logistic regression models to estimate odds ratios and 95% confidence intervals (95% CIs) to explore the association between deterioration to high depression levels and selected risk factors. RESULTS: Median depression levels among CHWs in Vietnam doubled from 3 (IQR = 2-7) before COVID-19 to 6 (IQR = 3-9) on the PHQ-9 scale during the Tet holiday outbreak. The proportion with normal/minimal levels decreased from 77.1% (95% CI = 74.4-79.7) to 50.9% (95% CI = 47.7-54) (p-value < 0.001), while the proportion of CHWs with moderate, moderately severe, and severe depression levels increased 4.3, 4.5, and five-fold, respectively. Less sleep and poor sleep quality, working in unfavorable work environments, and being involved in contact tracing and the organization of quarantine for suspected cases were associated with an increased risk of deterioration to high depression levels. CONCLUSIONS: We found a substantial increase in overall depression levels among CHWs in Vietnam due to their COVID-19 related work and a particularly worrisome rise in CHWs suffering from severe depression. CHWs are an indispensable yet often overlooked cadre of work in many low- and middle-income countries and shoulder a heavy psychological burden during the COVID-19 pandemic. Targeted psychological support for CHWs is needed to improve their mental health and to ensure the sustainability of community-based health interventions during COVID-19 and future epidemics.

Operational Gaps in Implementing the COVID-19 Case Investigation and Contact Tracing in Madhesh Province of Nepal, May-July 2021.

In Nepal, case investigation and contact tracing (CICT) was adopted as an important public health measure to reduce COVID-19 transmission. In this study, we assessed the performance of CICT in Madhesh Province of Nepal against national benchmarks, using routine programmatic data reported by district CICT teams. Between May and July 2021, 17,943 COVID-19 cases were declared in the province, among which case investigation was performed for 30% (95% CI: 29.6-31.0%) within 24 h (against 80% benchmark). As a result of case investigations, 6067 contacts were identified (3 contacts per 10 cases), of which 40% were traced and tested for SARS-CoV-2 infection (against 100% benchmark). About 60% of the contacts tested positive. At most 14% (95% CI: 13.1% to 14.9%) of traced contacts underwent a 14-day follow-up assessment (against 100% benchmark). We found the performance of the CICT program in Madhesh Province to be sub-optimal and call for corrective measures to strengthen CICT in the province and the country at large. Similar studies with wider geographical scope and longer time frames are needed to identify and address deficiencies in data recording and reporting systems for COVID-19, in low- and middle-income countries like Nepal and others.

Travel-associated SARS-CoV-2 transmission documented with whole genome sequencing following a long-haul international flight.

BACKGROUND: Multiple instances of flight-associated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during long-haul flights have been reported during the COVID-19 pandemic. However, comprehensive investigations of passenger risk behaviours, before, during and after the flight, are scarce. METHODS: To investigate suspected SARS-CoV-2 transmission during a flight from United Arab Emirates to Australia in July 2020, systematic, repeated polymerase chain reaction (PCR) testing of passengers in hotel quarantine was linked to whole genome sequencing. Epidemiological analyses of in-depth interviews covering behaviours during the flight and activities pre- and post-boarding were used to identify risk factors for infection. RESULTS: Seventeen of the 95 passengers from four different travel origins had PCR-confirmed infection yielding indistinguishable genomic sequences. Two of the 17 passengers were symptomatic within 2 days of the flight, and classified as co-primary cases. Seven secondary cases were seated within two rows of the co-primary cases, but five economy passengers seated further away and three business class passengers were also infected (attack rate = 16% [15/93]). In multivariable analysis, being seated within two rows of a primary case [odds ratio (OR) 7.16; 95% confidence interval (CI) 1.66-30.85] and spending more than an hour in the arrival airport (OR 4.96; 95% CI 1.04-23.60) were independent predictors of secondary infection, suggesting travel-associated SARS-CoV-2 transmission likely occurred both during and after the flight. Self-reported increased hand hygiene, frequent aisle walking and using the bathroom on the plane did not independently affect the risk of SARS-CoV-2 acquisition. CONCLUSIONS: This investigation identified substantial in-flight transmission among passengers seated both within and beyond two rows of the primary cases. Infection of passengers in separate cabin classes also suggests transmission occurred outside the cabin environment, likely at the arrival airport. Recognizing that transmission may occur pre- and post-boarding may inform contact tracing advice and improve efforts to prevent future travel-associated outbreaks.

Using 'infodemics' to understand public awareness and perception of SARS-CoV-2: A longitudinal analysis of online information about COVID-19 incidence and mortality during a major outbreak in Vietnam, July-September 2020.

BACKGROUND: Trends in the public perception and awareness of COVID-19 over time are poorly understood. We conducted a longitudinal study to analyze characteristics and trends of online information during a major COVID-19 outbreak in Da Nang province, Vietnam in July-August 2020 to understand public awareness and perceptions during an epidemic. METHODS: We collected online information on COVID-19 incidence and mortality from online platforms in Vietnam between 1 July and 15 September, 2020, and assessed their trends over time against the epidemic curve. We explored the associations between engagement, sentiment polarity, and other characteristics of online information with different outbreak phases using Poisson regression and multinomial logistic regression analysis. We assessed the frequency of keywords over time, and conducted a semantic analysis of keywords using word segmentation. RESULTS: We found a close association between collected online information and the evolution of the COVID-19 situation in Vietnam. Online information generated higher engagements during compared to before the outbreak. There was a close relationship between sentiment polarity and posts' topics: the emotional tendencies about COVID-19 mortality were significantly more negative, and more neutral or positive about COVID-19 incidence. Online newspaper reported significantly more information in negative or positive sentiment than online forums or social media. Most topics of public concern followed closely the progression of the COVID-19 situation during the outbreak: development of the global pandemic and vaccination; the unfolding outbreak in Vietnam; and the subsiding of the outbreak after two months. CONCLUSION: This study shows how online information can reflect a public health threat in real time, and provides important insights about public awareness and perception during different outbreak phases. Our findings can help public health decision makers in Vietnam and other low and middle income countries with high internet penetration rates to design more effective communication strategies during critical phases of an epidemic.