Heterogeneity in testing for infectious diseases

Testing strategies have varied widely between nation states during the COVID-19 pandemic, in intensity as well as methodology. Some countries have mainly performed diagnostic testing while others have opted for mass-screening for the presence of SARS-CoV-2 as well. COVID passport solutions have been introduced, in which access to several aspects of public life requires either testing, proof of vaccination or a combination thereof. This creates a coupling between personal activity levels and testing behaviour which, as we show, leverages the heterogeneous behaviours in the population and turns this heterogeneity from a disadvantage to an advantage for epidemic control.

Evaluation of effectiveness of mass screening for tuberculosis infection in children from 1 to 7 years old in Moscow

The objective: to evaluate effectiveness of mass screening for tuberculosis infection in children aged 1 to 7 years in different periods – before and after the use of tuberculosis recombinant allergen skin test (TRA) in primary health care as an additional diagnostic method.Subjects and Methods. The study was designed as continuous observational prospective-retrospective study. Two different periods were assessed: the first one was 2014-2016 when screening for tuberculosis infection was performed in all children from 1 to 17 years (inclusive) using Mantoux test with 2 TU PPD-L in pediatric primary health care, and then children suspected to have a positive reaction were referred to TB dispensary where they were examined with a skin test with TRA if necessary. The second period was from 2018 to 2020 when children of 1-7 years old were given Mantoux test and if tuberculosis infection was suspected, a skin test with TRA was done both in primary health care network and TB units. In the first 3 years, 1,864,137 children were examined and in the second 3 years, 2,078,800 children from 1 to 7 years old were examined.Results. Among children of 1-7 years old who were screened by two stages (initial Mantoux test, and then in those who had a positive reaction, the TRA test was used), only 10-12% of those referred to a phthisiologist were subject to dispensary follow-up. Thus, with the implementation of the new edict on screening for tuberculosis infection in children with two tests, this proportion has not changed compared to previous years, when screening was carried out only with one Mantoux test. The reason why almost 90% of the children who were referred to TB Dispensary were not subject to dispensary follow-up is the following: children who have had previous conversion of tuberculin tests, along with everyone else are again screened with Mantoux test despite being previously followed up by TB dispensary due to the primary infection.Recommendations:Currently, there is no division of Group VI into Subgroups A, B, C in the dispensary follow up grouping. Why should conversion of Mantoux test reaction from negative into positive not be considered an infection, and the increase in the reaction must be at least 6 mm.Since Order No. 124n of the Russian Ministry of Health allows testing with TRA in the primary health care in case of suspected infection, it is advisable to refer those who have already had this test to a phthisiologist.A child with conversion of Mantoux test should not be re-screened with Mantoux test but the TRA test should be used. If a positive reaction to the TRA test occurs for the first time, it should be considered as conversion of this test, and in this case the child should be examined by computed tomography (CT), and preventive therapy should be prescribed. If in subsequent years the TRA reaction increases by at least 6 mm after previous preventive therapy, the child should be re-referred for CT to rule out the development of active tuberculosis.

SARS-CoV-2 Saliva Mass Screening in Primary Schools: A 10-Week Sentinel Surveillance Study in Munich, Germany

Representative, actively collected surveillance data on asymptomatic SARS-CoV-2 infections in primary schoolchildren remain scarce. We evaluated the feasibility of a saliva mass screening concept and assessed infectious activity in primary schools. During a 10-week period from 3 March to 21 May 2021, schoolchildren and staff from 17 primary schools in Munich participated in the sentinel surveillance, cohort study. Participants were tested using the Salivette® system, testing was supervised by trained school staff, and samples were processed via reverse transcription quantitative polymerase chain reaction (RT-qPCR). We included 4433 participants: 3752 children (median age, 8 [range, 6–13] years; 1926 girls [51%]) and 681 staff members (median age, 41 [range, 14–71] years; 592 women [87%]). In total, 23,905 samples were processed (4640 from staff), with participants representing 8.3% of all primary schoolchildren in Munich. Only eight cases were detected: Five out of 3752 participating children (0.13%) and three out of 681 staff members (0.44%). There were no secondary cases. In conclusion, supervised Salivette® self-sampling was feasible, reliable, and safe and thus constituted an ideal method for SARS-CoV-2 mass screenings in primary schoolchildren. Our findings suggest that infectious activity among asymptomatic primary schoolchildren and staff was low. Primary schools appear to continue to play a minor role in the spread of SARS-CoV-2 despite high community incidence rates.

Newborn Screening in Japan—2021

Japan’s Newborn Mass Screening (NBS) was started in 1977 for amino acid metabolism disorders (phenylketonuria (PKU), homocystinuria, maple syrup urine, histidineemia (discontinued in 1993)) and galactosemia at the national level as a national project [...]

Novel Multi-Modal Throat Inflammation and Chest Radiography based Early-Diagnosis and Mass-Screening of COVID-19

Background: The upsurge of COVID-19 has received significant international contemplation considering its life-threatening ramifications. To ensure that the susceptible patients can be quarantined to control the spread of the disease during the incubation period of the coronavirus, it becomes imperative to automatically and non-invasively mass screen patients. The diagnosis using RT-PCR is arduous and time-consuming. Currently, the non-invasive mass screening of susceptible cases is being performed by utilizing the thermal screening technique. However, with the consumption of paracetamol, the symptoms of fever can be suppressed. Methods: A novel multi-modal approach has been proposed. Throat inflammation-based mass screening and early prediction followed by Chest X-Ray based diagnosis have been proposed. Depth-wise separable convolutions have been utilized by fine-tuning Xception Net and Mobile Net architectures. NADAM optimizer has been leveraged to promote faster convergence. Results: The proposed method achieved 91% accuracy on the throat inflammation identification task and 96% accuracy on chest radiography conducted on the dataset. Conclusion: Evaluation of the proposed method indicates promising results and henceforth validates its clinical reliability. The future direction could be working on a larger dataset in close collaboration with the medical fraternity.

Five-year follow-up of new cases after a coeliac disease mass screening

ObjectiveWe previously performed a population-based mass screening of coeliac disease in children aged 12 years in two birth cohorts resulting in 296 seropositive children, of whom 242 were diagnosed with coeliac disease after duodenal biopsies. In this follow-up study, we wanted to identify new cases in the screening population that tested negative—either converting from potential coeliac disease (seropositive but normal duodenal mucosa) or converting from seronegative at screening to diagnosed coeliac disease.MethodsAll seropositive children were invited to a follow-up appointment 5 years after the screening with renewed serological testing and recommended endoscopic investigation if seropositive. Seronegative children in the screening study (n=12 353) were linked to the National Swedish Childhood Coeliac Disease Register to find cases diagnosed in healthcare during the same period.ResultsIn total, 230 (77%) came to the follow-up appointment, including 34 of 39 with potential coeliac disease. Of these, 11 (32%) had converted to coeliac disease. One new case was found in the National Swedish Childhood Coeliac Disease Register who received the diagnosis through routine screening in children with type 1 diabetes.ConclusionsThere is a high risk of conversion to coeliac disease among those with potential disease. However, a negative screening test was associated with a very low risk for a clinical diagnosis within a follow-up period of 5 years.

Is mass screening enough to control tuberculosis in Ecuador’s prisons?

Objective: To evaluate mass screening campaigns for tuberculosis in prisoners in Ecuador. Material and method: Cross-sectional study of Chronic Cough (CC) detected amongst inmates who entered two prisons in Ecuador between January and December 2016 (n = 12,365). The time distribution of the CCs was analyzed with the uniformity test and its relationship with the diagnosed cases of PTB, the prevalence of PTB was calculated. A logistic regression model was performed to determine the factors modifiers of PTB positivity. Results: 1.332 chronic cougher were recorded, the positivity rate was 17.3% (95% CI, 15.1-19.4), and the prevalence was 1.9% (95% CI, 1.6 - 2.1). There was an absence of uniformity in the detection and diagnosis by epidemiological weeks; there was a positive correlation between CC and PTB cases. The positivity rate was associated with the prison with the highest density (adjusted OR 3.8; 95% CI, 2.5-5.5). Discussion: Massive screening campaigns are not enough to control tuberculosis in Ecuador’s prisons. The incidence found is high. It is necessary to strengthen the diagnostic process to treat all the cases found and thus break the chain of transmission.

A semi-automated, isolation-free, high-throughput SARS-CoV-2 reverse transcriptase (RT) loop-mediated isothermal amplification (LAMP) test

Shortages of reverse transcriptase (RT)-polymerase chain reaction (PCR) reagents and related equipment during the COVID-19 pandemic have demonstrated the need for alternative, high-throughput methods for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-mass screening in clinical diagnostic laboratories. A robust, SARS-CoV-2 RT-loop-mediated isothermal amplification (RT-LAMP) assay with high-throughput and short turnaround times in a clinical laboratory setting was established and compared to two conventional RT-PCR protocols using 323 samples of individuals with suspected SARS-CoV-2 infection. Limit of detection (LoD) and reproducibility of the isolation-free SARS-CoV-2 RT-LAMP test were determined. An almost perfect agreement (Cohen’s kappa > 0.8) between the novel test and two classical RT-PCR protocols with no systematic difference (McNemar’s test, P > 0.05) was observed. Sensitivity and specificity were in the range of 89.5 to 100% and 96.2 to 100% dependent on the reaction condition and the RT-PCR method used as reference. The isolation-free RT-LAMP assay showed high reproducibility (Tt intra-run coefficient of variation [CV] = 0.4%, Tt inter-run CV = 2.1%) with a LoD of 95 SARS-CoV-2 genome copies per reaction. The established SARS-CoV-2 RT-LAMP assay is a flexible and efficient alternative to conventional RT-PCR protocols, suitable for SARS-CoV-2 mass screening using existing laboratory infrastructure in clinical diagnostic laboratories.