Getting Jab or Regular Test: Observations from an Impulsive Epidemic COVID-19 Model.

Several safe and effective vaccines are available to prevent individuals from experiencing severe illness or death as a result of COVID-19. Widespread vaccination is widely regarded as a critical tool in the fight against the disease. However, some individuals may choose not to vaccinate due to vaccine hesitancy or other medical conditions. In some sectors, regular compulsory testing is required for such unvaccinated individuals. Interestingly, different sectors require testing at various frequencies, such as weekly or biweekly. As a result, it is essential to determine the optimal testing frequency and identify underlying factors. This study proposes a population-based model that can accommodate different personal decision choices, such as getting vaccinated or undergoing regular tests, as well as vaccine efficacies and uncertainties in epidemic transmission. The model, formulated as impulsive differential equations, uses time instants to represent the reporting date for the test result of an unvaccinated individual. By employing well-accepted indices to measure transmission risk, including the basic reproduction number, the peak time, the final size, and the number of severe infections, the study shows that an optimal testing frequency is highly sensitive to parameters involved in the transmission process, such as vaccine efficacy, disease transmission rate, test accuracy, and existing vaccination coverage. The testing frequency should be appropriately designed with the consideration of all these factors, as well as the control objectives measured by epidemiological quantities of great concern.

Patients utilizing emergency medical services - Does facility type matter?

BACKGROUND: Emergency departments (EDs) play a critical role in the US healthcare system. As freestanding EDs (FSEDs) are integrated into the acute care landscape, local EMS providers are transporting to these facilities, which may be closer in proximity and provide faster turnaround times. We hypothesized that patients transported via EMS to a freestanding ED required fewer tests and are admitted less frequently than those transported to a HBED. Our objective was to compare testing frequency and admission rates between patients transported via EMS to a FSED vs. HBED. METHODS: This was a retrospective cohort study of all patients who presented within a large integrated hospital system via EMS to one of 10 HBEDs or one of 6 FSEDs between April 1, 2020 - May 1, 2021. Categorical variables are presented as frequencies and percentages and comparisons between groups were obtained using chi squared tests. Continuous variables are presented as mean and standard deviation and p-values comparing groups were obtained using t-tests. Multiple logistic regression was used to assess the effect of ED type on admission status, labs ordered, and testing performed. RESULTS: A total of 123,120 encounters were included in our study. Mean age at the FSEDs was 59.9 vs. 61.3 at the HBEDs. At the FSEDs 55.6% (n = 4675) were female vs. 53.0% (n = 60,809) at the HBEDs. At the FSEDs 82.0% (n = 6805) were White vs. 60.7% (n = 68,430) at the HBEDs. We found 50.0% (n = 3974) had Medicare at the FSEDs vs 50.9% (n = 55,372) at the FSEDs. At the FSEDs, 69.5% (n = 5846) had bloodwork vs. 82.4% (n = 94,512) at the HBEDs; 68.3% (n = 5745) had an x-ray at the FSEDs vs. 70.7% (n = 81,089) at the HBEDs; 40.1% (n = 3370) had a CT scan at the FSEDs vs. 44.9% (n = 51,503) at the HBEDs; and 40.6% (n = 3412) were admitted at the FSEDs vs. 56.1% (n = 64,355) at the HBEDs. After controlling for Charlson Comorbidity Index, acuity, age, gender, sex, insurance and race, patients in FSEDs were 35% less likely to be admitted as compared to HBEDs. CONCLUSION: Patients brought in via EMS to a FSED were less likely to have blood work, x-ray, or CT scan, and were less likely to be admitted to the hospital than those transported to a HBED.

The Household Secondary Attack Rate of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Rapid Review.

BACKGROUND: Although much of the public health effort to combat coronavirus disease 2019 (COVID-19) has focused on disease control strategies in public settings, transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within households remains an important problem. The nature and determinants of household transmission are poorly understood. METHODS: To address this gap, we gathered and analyzed data from 22 published and prepublished studies from 10 countries (20 291 household contacts) that were available through 2 September 2020. Our goal was to combine estimates of the SARS-CoV-2 household secondary attack rate (SAR) and to explore variation in estimates of the household SAR. RESULTS: The overall pooled random-effects estimate of the household SAR was 17.1% (95% confidence interval [CI], 13.7-21.2%). In study-level, random-effects meta-regressions stratified by testing frequency (1 test, 2 tests, >2 tests), SAR estimates were 9.2% (95% CI, 6.7-12.3%), 17.5% (95% CI, 13.9-21.8%), and 21.3% (95% CI, 13.8-31.3%), respectively. Household SARs tended to be higher among older adult contacts and among contacts of symptomatic cases. CONCLUSIONS: These findings suggest that SARs reported using a single follow-up test may be underestimated, and that testing household contacts of COVID-19 cases on multiple occasions may increase the yield for identifying secondary cases.

Serum lithium test requesting across three UK regions: an evaluation of adherence to monitoring guidelines.

BACKGROUND: Bipolar disorder is the fourth most common mental health condition, affecting ~ 1% of UK adults. Lithium is an effective treatment for prevention of relapse and hospital admission, and is widely recommended as a first-line treatment. We previously showed in other areas that laboratory testing patterns are variable with sub-optimal conformity to guidance. We therefore examined lithium results and requesting patterns relative to monitoring recommendations. METHODS: Data on serum lithium levels and intervals between requests were extracted from Clinical Biochemistry laboratory information systems at the University Hospitals of North Midlands, Salford Royal Foundation Trust and Pennine Acute Hospitals from 2012 to 2018 (46,555 requests; 3371 individuals). Data were examined with respect to region/source of request, age and sex. RESULTS: Across all sites, lithium levels on many requests were outside the recommended UK therapeutic range (0.4-0.99 mmol/L); 19.2% below the range and 6.1% above the range (median [Li]: 0.60 mmol/L). A small percentage were found at the extremes (3.2% at < 0.1 mmol/L, 1.0% at ≥1.4 mmol/L). Most requests were from general practice (56.3%) or mental health units (34.4%), though those in the toxic range (≥1.4 mmol/L) were more likely to be from secondary care (63.9%). For requesting intervals, there was a distinct peak at 12 weeks, consistent with guidance for those stabilised on lithium therapy. There was no peak at 6 months, as recommended for those aged < 65 years on unchanging therapy, though re-test intervals in this age group were more likely to be longer. There was a peak at 0-7 days, reflecting those requiring closer monitoring (e.g. treatment initiation, toxicity). However, for those with initial lithium concentrations within the BNF range (0.4-0.99 mmol/L), 69.4% of tests were requested outside expected testing frequencies. CONCLUSIONS: Our data showed: (a) lithium levels are often maintained at the lower end of the recommended therapeutic range, (b) patterns of lithium results and testing frequency were comparable across three UK sites with differing models of care and, (c) re-test intervals demonstrate a noticeable peak at the recommended 3-monthly, but not at 6-monthly intervals. Many tests were repeated outside expected frequencies, indicating the need for measures to minimise inappropriate testing.

Factors related to HIV testing frequency in MSM based on the 2011-2018 survey in Tianjin, China: a hint for risk reduction strategy.

BACKGROUND: In recent years, HIV testing has become one of the effective strategies to reduce the risk of the infection. Frequent quarterly HIV testing can be cost effective. Therefore, an in-depth study of factors related to the testing behavior of men who have sex with men (MSM) were analyzed to optimize intervention strategies. METHODS: From March 2011 to October 2018, the project was implemented in a Tianjin (China) bathhouse, and 5165 MSM were surveyed using snowball sampling. Factors related to HIV testing behavior were analyzed by ordinal logistic regression analysis after grouping according to testing frequency, and comprehensive analysis was performed. RESULTS: The multivariate logistic analysis showed that 6 variables including young MSM (OR = 0.67, 95% CI: 0.49-0.92, p = 0.01), low-educated MSM (OR = 0.60, 95% CI: 0.48-0.77, p < 0.0001), low HIV/AIDS knowledge (95% CI: 0.57-0.83, p < 0.0001), marital status (OR = 1.30, 95% CI: 1.07-1.57, p = 0.007), acceptance of condom promotion and distribution (OR = 14.52, 95% CI: 12.04-17.51, p < 0.0001), and frequency of condom use (p < 0.05) could link to HIV testing behaviors. CONCLUSIONS: In order to achieve the 95-95-95 goal, target publicity, HIV/AIDS education and promotion of HIV self-testing kits should be carried out to encourage frequent HIV testing among MSM who are young (especially students), married to women, poorly educated and who are reluctant to always use condoms.

Increases in HIV Testing Frequency in Australian Gay and Bisexual Men are Concentrated Among PrEP Users: An Analysis of Australian Behavioural Surveillance Data, 2013-2018.

Increasing HIV testing frequency in gay and bisexual men (GBM) is critical to reducing the time between HIV infection and diagnosis. Using anonymous national behavioural surveillance data (2013-2018) from 43,753 surveys of Australian GBM, we examined HIV testing frequency trends and factors differentiating PrEP-users, non-PrEP-users reporting two or more tests in the previous year, and non-PrEP-users reporting less frequent testing. The proportion tested at least annually increased from 64.4% in 2013 to 70.8% in 2018 (p-trend < 0.001), and from 73.9% to 84.6% among the 51.6% of men classified as higher-risk. Among higher-risk men, having two or more tests in the previous year increased from 48.0% to 69.3% (p-trend < 0.001). Among higher-risk non-PrEP-users, it increased from 47.2% to 54.8% (p-trend < 0.001), however, there was a decrease since 2016 (p-trend < 0.001). Among PrEP-users, it increased from 82.1% in 2013 to 97.3% in 2018 (p-trend < 0.001). Non-PrEP-using higher-risk men having less frequent tests reported lower risk than PrEP-users and non-PrEP-using men reporting two or more tests in the previous year. However, recent risk behaviour was not uncommon: nearly half reported condomless sex; one-fifth reported receptive condomless sex with ejaculation; over half reported group sex; one-quarter used drugs for the purposes of sex; and one-fifth had more than ten sex partners. Efforts are needed to encourage frequent testing and PrEP use among non-PrEP-users who are at higher-risk.

The role of frequent HIV testing in diagnosing HIV in men who have sex with men.

OBJECTIVES: In the UK, quarterly HIV testing is recommended for high-risk men who have sex with men (MSM). In this manuscript we determined the risk of being newly diagnosed with HIV in MSM by their HIV testing history, considering both the frequency and periodicity of testing. METHODS: Data on HIV incidence in MSM attending a sexual health clinic (SHC) in England in 2013-2014 with testing history (previous 2 years) were obtained from GUMCAD, the national sexually transmitted infection (STI) surveillance system in England. HIV testing patterns among MSM were defined using the frequency and periodicity of testing, based on 3 month intervals, in the year preceding the first attendance during the study period. Cox proportional hazards regression was used to determine the association between HIV testing pattern and time to HIV diagnosis with and without adjustment for demographic confounders. Analyses were stratified by risk stratum, with 'high risk' defined as a history of a bacterial STI in the past year. Adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) are reported. RESULTS: Among the 37 702 HIV-negative MSM attending an SHC in 2013-2014, 1105 (3%) were diagnosed with HIV infection within 1 year of their first attendance. The probability of HIV diagnosis was highest in MSM who were tested quarterly compared with those who were not tested in the past year (aHR 2.51; 95% CI 1.33-4.74); this increased 1.8-fold among high-risk MSM (aHR 4.48; 95% CI 0.97-21.17). CONCLUSIONS: The probability of subsequent HIV diagnosis was greatest in high-risk MSM who were tested most frequently. Quarterly HIV testing increased the likelihood of identifying undiagnosed HIV infection and should remain a continued recommendation for high-risk MSM.

International normalised ratio monitoring in the community populations of the Auckland and Northland regions of New Zealand: time in therapeutic range and frequency of testing.

BACKGROUND: Warfarin remains a commonly used anticoagulant for the treatment and prevention of thrombosis. To balance the risks and benefits of therapy, monitoring of the international normalised ratio (INR) is necessary. Patients derive most benefit from warfarin when they spend ≥65% of time in the therapeutic range (INR 2-3). We performed an analysis of INR monitoring for the Auckland and Northland regions of New Zealand in order to estimate anticoagulation control and appropriateness of testing at the population level. METHODS: INR test results and patient demographics (age and sex) were extracted from the laboratory information system of Labtests and Northland Pathology Laboratories for the period of 1 January 2016 to 27 July 2016. RESULTS: We included 126 184 INR results from 10 922 patients. The median age of patients represented was 74 years and 57% were male. The overall mean time in therapeutic range was 63%, with a mean interval between INR tests of 14 days. CONCLUSION: Our results indicate that anticoagulant control in our communities could be improved, and that inappropriately frequent INR testing should be redressed. Appropriate interventions could lead to net clinical benefits and reduce resource misallocation.

Epidermal growth factor receptor and anaplastic lymphoma kinase testing and mutation prevalence in patients with advanced non-small cell lung cancer in Switzerland: A comprehensive evaluation of real world practices.

In order to improve outcomes, identification of the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) genes has become crucial in advanced non-small-cell lung cancer (NSCLC). The aim of the present study is to analyse time trends and frequency of testing, factors affecting testing as well as prevalence of mutations in the Swiss population. We analysed EGFR and ALK testing in a cohort of patients with newly diagnosed metastasised non-squamous NSCLC in the catchment area of the cancer registry Eastern Switzerland in the years 2008-2014. We analysed prevalence of mutations and studied clinicopathological characteristics and survival of tested and non-tested patients and of patients with and without mutations. Among 718 patients identified, 11% (51/447) harboured an EGFR mutation in the exons 18, 19 or 21 and further 12% (31/265) showed a positive test result for ALK rearrangements. In non-smokers the proportions of mutations were 31% and 23% respectively. Testing rates increased over time and reached 79% in 2014. We observed significantly lower testing rates and poorer survival in elderly, patients with limited life expectancy and patients treated at hospitals not involved in clinical research. Outcomes can be further improved in a considerable proportion of patients with advanced non-squamous NSCLC.

Evaluation of hyperketonemia risk period and screening protocols for early-lactation dairy cows.

The objectives of this study were to describe the onset of hyperketonemia, the number of positive hyperketonemia test results, and the duration of the longest hyperketonemic period during the first 42 d in milk (DIM) in dairy cows. Furthermore, we set out to evaluate test characteristics of single and repeated measurements of ß-hydroxybutyric acid (BHBA) during this period to diagnose hyperketonemia. Using an electronic handheld meter, 252 cows from 3 farms were tested twice weekly for hyperketonemia (blood BHBA ≥1.2 mmol/L) during the first 42 DIM, resulting in 12 test results per cow (i.e., in lactation wk 0.5 to 6). Prevalence and incidence of hyperketonemia were calculated for the 12 examination days and the 42-d period, respectively. Test characteristics for the diagnosis of hyperketonemia were calculated for 4 different testing scenarios (testing all cows 1, 2, 3, or 6 times during the first 42 DIM) and 2 different gold-standard definitions (BHBA ≥1.2 mmol/L at least once during the observation period or BHBA ≥1.2 mmol/L at least twice during the observation period). Mean prevalence of hyperketonemia was 11.8%, ranging from 9.6% in lactation wk 0.5 and 2.0 to 14.6% in lactation wk 5.5. In total, 134 cows (53.2%) had at least 1 positive hyperketonemia test result during the whole 42-d period. Of these cows, 46.3% had only 1 positive result. The median first positive hyperketonemia test result was in lactation wk 2.0 [interquartile range (IQR) 1.0-3.5]. Median frequency of positive test results in cows affected by hyperketonemia was 2 positive test results (IQR 1-3). Median duration of the longest hyperketonemic period per cow affected was 1 examination interval (3-4 d; IQR 1-2). Considering a minimum of 1 positive hyperketonemia test result during the first 42 DIM as the gold standard, sensitivity of a single BHBA measurement during this period to diagnose hyperketonemia was 21%. A weekly testing protocol had a sensitivity of 72%. Specificity was 100% in both cases. Considering a minimum of 2 positive hyperketonemia test results as the gold standard, sensitivity and specificity of a single BHBA measurement during the first 42 DIM were 33 and 97%, respectively. A weekly testing protocol provided sensitivity and specificity of 91 and 83%, respectively. We conclude that the risk period for hyperketonemia lasts at least until lactation wk 6, which should be considered when planning hyperketonemia screening programs. Test characteristics of screening protocols depend on testing frequency.

Optimization of time interval for the measurement of plasma lipids for cardiovascular disease risk assessment.

BACKGROUND: Lipid testing for atherosclerotic cardiovascular disease (ASCVD) risk is often performed every 4-6 years, but we hypothesized that the optimum time interval may vary depending on baseline risk. RESEARCH DESIGN AND METHODS: Using lipid values and other risk factors from the National Health and Nutrition Examination Survey (NHANES) (n = 9,704), we calculated a 10-year risk score with the pooled-cohort equations. Future risk scores were predicted by increasing age and projecting systolic blood pressure (SBP) and lipid changes, using the mean-percentile age group change in NHANES for SBP (n = 17,329) and the Lifelines Cohort study for lipids (n = 133,540). The crossing of high and intermediate-risk thresholds were calculated by time to determine optimum intervals for lipid testing. RESULTS: Time to crossing risk thresholds depends on baseline risk, but the mean increase in the risk score plateaus at 1% per year for those with a baseline 10-year risk greater than 15%. Based on these findings, we recommend the following maximum time intervals for lipid testing: baseline risk < 15%: 5-years, 16%: 4-years, 17%: 3-years, 18%: 2-years, and 19%: ≤1-year. CONCLUSIONS: Testing patients for lipids who have a higher baseline risk more often could identify high-risk patients sooner, allowing for earlier and more effective therapeutic intervention.

Adherence to PKU guidelines among patients with phenylketonuria: A cross-sectional national multicenter survey-based study in Argentina, Brazil, and Mexico.

Objective: To characterize adherence to Phenylketonuria (PKU) management practices among PKU patients treated at reference sites around Argentina, Brazil, and Mexico. Methods: This is a retrospective, observational, multicenter, and multinational survey-based study using aggregate data. From an initial list of 40 sites, 22 clinicians expressed interest in completing the survey, with 20 clinicians from 20 unique sites fulfilling all the study criteria. The Survey contained 28 questions, including respondent's clinic characteristics, clinic PKU treatment recommendations, and patient adherence to clinic recommendations. Survey was available in local languages, and the respondents were asked to consult their clinic records to complete their responses. Adherence was assessed by target blood phenylalanine (Phe), target blood testing frequency, and clinic visits. Results: A total of 1077 (out of 1377) actively managed PKU patients (seen in the clinic in the last 3 years) from 13 clinics in Brazil, six in Argentina, and one in Mexico were analyzed. Upper blood Phe target was set over 360 µMol/L in 70% of the clinics for adult patients. Around 40% of the patients >30 years old had Phe blood tests done twice a year or less, with 60% of the clinics recommending semestral visits for adults <30 years old. Twice a month was the most common frequency of visits for <1 year old. The COVID-19 pandemic was a disruptor for frequency of visits and exams. Conclusions: These results show that there is still room for improvement in terms of adherence, namely in adults and older children. More efforts must be made to educate patients and healthcare professionals about the importance of treatment adherence, accompanied by public policies that expand access to pharmacological and dietary treatment with diversity and quality to improve adherence to adequate blood Phe levels.

Impact of screening and doxycycline prevention on the syphilis epidemic among men who have sex with men in British Columbia: a mathematical modelling study.

Background: Men who have sex with men (MSM) in British Columbia (BC) are disproportionately affected by infectious syphilis and HIV. In this study, we developed a co-interaction model and evaluated the impact and effectiveness of possible interventions among different MSM subgroups on the syphilis epidemic. Methods: We designed a deterministic compartmental model, which stratified MSM by HIV status and HIV pre-exposure prophylaxis (HIV-PrEP) usage into (1) HIV-negative/unaware MSM (HIV-PrEP not recommended, not on HIV-PrEP), (2) HIV-negative/unaware MSM with HIV-PrEP recommended (not on HIV-PrEP), (3) HIV-negative/unaware MSM actively on HIV-PrEP, and (4) MSM diagnosed with HIV. We estimated the effect of scaling up syphilis testing frequency from Status Quo to six-, four-, and three-months, increasing the percentage of MSM using doxycycline prevention (Doxy-P) to 25%, 50%, and 100% of the target level, and a combination of both among subgroups (2)-(4). We also assessed the impact of these interventions on the syphilis incidence rates from 2020 to 2034 in comparison to the Status Quo scenario where no intervention was introduced. Findings: Under the Status Quo scenario, with the expansion of the HIV-PrEP program to improve syphilis testing, the syphilis incidence rate was estimated to peak at 16.1 [Credible Interval (CI):14.2-17.9] per 1,000 person-years (PYs) in 2023 and decrease to 6.7 (CI:3.8-10.9) per 1,000 PYs by 2034. The syphilis incidence rate in 2034 was estimated at 0.7 (0.3-1.3) per 1,000 PYs if MSM diagnosed with HIV could be tested every four months, and at 1.5 (0.7-3.0) per 1,000 PYs if HIV-negative/unaware MSM actively on HIV-PrEP could be tested every three months. By achieving 100% of the target coverage of Doxy-P, the syphilis incidence rate was estimated at 1.4 (0.5-3.4) if focusing on MSM diagnosed with HIV, and 2.6 (1.2-5.1) per 1,000 PYs if focusing on HIV-negative/unaware MSM actively on HIV-PrEP. Under the combined interventions, the syphilis incidence rate could be as low as 0.0 (0.0-0.1) and 0.8 (0.3-1.8) per 1,000 PYs, respectively. Interpretation: The HIV-PrEP program in BC plays a crucial role in increasing syphilis testing frequency among high-risk MSM and reducing syphilis transmission among this group. In addition, introducing Doxy-P can be an effective complementary strategy to minimize syphilis incidence, especially among MSM diagnosed with HIV. Funding: This work was funded by the Canadian Institutes of Health Research.

Adaptive Sentinel Testing in Workplace for COVID-19 Pandemic.

Testing and isolation of infectious employees is one of the critical strategies to make the workplace safe during the pandemic for many organizations. Adaptive testing frequency reduces cost while keeping the pandemic under control at the workplace. However, most models aimed at estimating test frequencies were structured for municipalities or large organizations such as university campuses of highly mobile individuals. By contrast, the workplace exhibits distinct characteristics: employee positivity rate may be different from the local community because of rigorous protective measures at workplace, or self-selection of co-workers with common behavioral tendencies for adherence to pandemic mitigation guidelines. Moreover, dual exposure to COVID-19 occurs at work and home that complicates transmission modeling, as does transmission tracing at the workplace. Hence, we developed bi-modal SEIR (Susceptible, Exposed, Infectious, and Removed) model and R-shiny tool that accounts for these differentiating factors to adaptively estimate the testing frequency for workplace. Our tool uses easily measurable parameters: community incidence rate, risks of acquiring infection from community and workplace, workforce size, and sensitivity of testing. Our model is best suited for moderate-sized organizations with low internal transmission rates, no-outward facing employees whose position demands frequent in-person interactions with the public, and low to medium population positivity rates. Simulations revealed that employee behavior in adherence to protective measures at work and in their community, and the onsite workforce size have large effects on testing frequency. Reducing workplace transmission rate through workplace mitigation protocols and higher sensitivity of the test deployed, although to a lesser extent. Furthermore, our simulations showed that sentinel testing leads to only marginal increase in the number of infections even for high community incidence rates, suggesting that this may be a cost-effective approach in future pandemics. We used our model to accurately guide testing regimen for three campuses of the Jackson Laboratory.

Optimal Frequency of Hepatitis C Virus (HCV) RNA Testing for Detection of Acute HCV Infection Among At-risk People With Human Immunodeficiency Virus: A Multicenter Study.

Using 3-stage pooled-plasma hepatitis C virus (HCV) RNA testing performed quarterly among at-risk people with human immunodeficiency virus (PWH), we found that if testing had been performed every 6 or 12 months, 58.6%-91.7% of PWH who recently acquired HCV would be delayed for diagnosis and might contribute to onward HCV transmission with longer durations.

Large-scale frequent testing and tracing to supplement control of Covid-19 and vaccination rollout constrained by supply.

Non-pharmaceutical interventions (NPI) were implemented all around the world in the fight against COVID-19: Social distancing, shelter-in-place, mask wearing, etc. to mitigate transmission, together with testing and contact-tracing to identify, isolate and treat the infected. The majority of countries have relied on the former measures, followed by a ramping up of their testing and tracing capabilities. We present here the cases of South Korea, Italy, Canada and the United States, as a look back to lessons that can be drawn for controlling the pandemic, specifically through the means of testing and tracing. By fitting a disease transmission model to daily case report data in each of the four countries, we first show that their combination of social-distancing and testing/tracing have had a significant impact on the evolution of their first wave of pandemic curves. We then consider the hypothetical scenario where the only NPI measures implemented past the first pandemic wave consisted of isolating individuals due to repeated, country-scale testing and contact tracing, as a mean of lifting social distancing measures without a resurgence of COVID-19. We give estimates on the average isolation rates needed to occur in each country. We find that testing and tracing each individual of a country, on average, every 4.5 days (South Korea), 5.7 days (Canada), 6 days (Italy) and 3.5 days (US), would have been sufficient to mitigate their second pandemic waves. We also considered the situation in Canada to see how a frequent large-scale asymptomatic testing and contact tracing could have been used in combination with vaccination rollout to reduce the infection in the population. This could offer an alternative approach towards preventing and controlling an outbreak when vaccine supply is limited, while testing capacity has been increasingly enhanced.

The stochastic dynamics of early epidemics: probability of establishment, initial growth rate, and infection cluster size at first detection.

Emerging epidemics and local infection clusters are initially prone to stochastic effects that can substantially impact the early epidemic trajectory. While numerous studies are devoted to the deterministic regime of an established epidemic, mathematical descriptions of the initial phase of epidemic growth are comparatively rarer. Here, we review existing mathematical results on the size of the epidemic over time, and derive new results to elucidate the early dynamics of an infection cluster started by a single infected individual. We show that the initial growth of epidemics that eventually take off is accelerated by stochasticity. As an application, we compute the distribution of the first detection time of an infected individual in an infection cluster depending on testing effort, and estimate that the SARS-CoV-2 variant of concern Alpha detected in September 2020 first appeared in the UK early August 2020. We also compute a minimal testing frequency to detect clusters before they exceed a given threshold size. These results improve our theoretical understanding of early epidemics and will be useful for the study and control of local infectious disease clusters.

Tap out: reducing waterborne Pseudomonas aeruginosa transmission in an intensive care unit.

BACKGROUND: Pseudomonas aeruginosa is a ubiquitous and important opportunistic pathogen in immunocompromised or critically ill patients. Nosocomial P. aeruginosa outbreaks have been associated with hospital water sources. AIM: To describe engineering interventions to minimize contamination of water outlets and the subsequent clinical impact. METHODS: New tap outlets were fitted at selected outlets across the intensive care unit (ICU). Laboratory testing demonstrated that, following artificial contamination with P. aeruginosa, these taps could be effectively decontaminated using a thermal washer-disinfector. Water samples were collected weekly from new outlets on the ICU over an eight-month period and tested for the enumeration of P. aeruginosa via membrane filtration. Surveillance of P. aeruginosa from clinical specimens was routinely undertaken. FINDINGS: Prior to the interventions, water sampling on ICU indicated that 30% of the outlets were positive for P. aeruginosa at any one time, and whole genome sequencing data suggested at least 30% transmission from water to patient. Since their installation, weekly sampling of the new tap outlets has been negative for P. aeruginosa, and the number of P. aeruginosa clinical isolates has fallen by 50%. CONCLUSION: Installation and maintenance of tap outlets free of P. aeruginosa can substantially reduce the number of P. aeruginosa clinical isolates in an ICU.

Effectiveness of self-testing kits availability on improving HIV testing frequency for chinese men who have sex with men and their sexual partners: a protocol for a multicenter randomised controlled trial.

INTRODUCTION: HIV epidemic is increasing among men who have sex with men (MSM) in China, yet HIV testing uptake remains low. As an emerging approach, HIV self-testing (HIVST) has the potential to promote HIV testing coverage and frequency in this population. However, evidence of the effectiveness on implementation of HIVST among Chinese MSM and their sexual partners is scarce. METHODS AND ANALYSIS: The randomised controlled trial will be performed in Changsha, Changde, Shaoyang and Yiyang, Hunan province, China, recruiting 184 recent testers (men who had at least one HIV test within the past 2 years) and 26 non-recent testers (men who did not have HIV tests within 2 years or never had an HIV test). Eligible men will be randomly divided 1:1 into two groups: intervention (with free HIVST kits plus site-based HIV testing services) and control (site-based HIV testing services only). Participants in the intervention group will be provided with two free finger-prick-based HIVST kits, and can apply for two to four kits every 3 months for 1 year.Participants in both groups will complete questionnaires via WeChat at five separate times: baseline, third, sixth, ninth and twelfth month. The primary outcome is the mean number of HIV tests for MSM over the 12-month study period. The secondary outcome is the mean number of HIV tests for sexual partners of MSM over the 12-month study period. The tertiary outcomes are the self-reported proportion of consistent condom usage for anal sex, and the numbers of sexual partners during the 12-month study period. ETHICS AND DISSEMINATION: The study has been approved by the Institutional Review Board of Behavioural and Nursing Research in Xiangya School of Nursing of Central South University, China (2018002). Study results will be disseminated through conferences and academic journals. TRIAL REGISTRATION NUMBER: ChiCTR1800015584; Pre-results.

Use of an integrated strip-free blood glucose monitoring system increases frequency of self-monitoring and improves glycemic control: Results from the ExAct study.

AIMS: We investigated the impact of using an integrated, strip-free system compared to the use of single-strip systems on testing frequency and glycemic control in individuals with insulin-treated diabetes. METHODS: This multinational, comparative, cluster-randomized, observational study included 311 patients with type 1 and insulin-treated type 2 diabetes who were performing SMBG at suboptimal frequencies. Sites were cluster-randomized to "integrated strip-free" system (EXP group) or any "single-strip" system (CNL group). Testing frequency and HbA1c were measured at baseline, 12 weeks and 24 weeks. RESULTS: At week 24, the EXP group showed an increase in SMBG frequency from baseline of 4.17 tests/week (95% CI 2.76, 5.58) compared with an increase of 0.53 tests/week (95% CI -0.73, 1.79) among CNL patients, resulting in a between-group difference of 3.63 tests/week (p < 0.0002). Mixed-effects models for repeated measurements (MMRM) controlling for baseline frequency of testing, country and clinical site confirmed a higher SMBG testing frequency in the EXP group compared to the CNL group, with a between-group difference of 2.70 tests/week (p < 0.01). Univariate analysis showed greater HbA1c reductions in the EXP group than CNL group: -0.44% (95% CI -0.59, -0.29) vs. -0.13% (95% CI -0.27, 0.01), respectively, p < 0.0002. MMRM analyses confirmed these HbA1c reductions. A greater percentage of EXP than CNL patients achieved HbA1c reductions of ≥0.5%: 45.1% vs. 29.1%, respectively, p < 0.01. CONCLUSIONS: The use of an integrated, strip-free SMBG system improved testing adherence and was associated with improvements in glycemic control.