Analysis of COVID-19 Infection Chains in a School Setting: Data From a School-Based rRT-PCR-Gargle Pool Test System.

BACKGROUND: School testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was implemented in some countries to monitor and prevent SARS-CoV-2 transmissions. Here, we analyze infection chains in primary schools and household members of infected students based on systematic real-time reverse-transcriptase polymerase-chain-reaction (rRT-PCR)-gargle pool testing. METHODS: Students and school staff (N = 4300) of all 38 primary schools in the rural county of Cham, Germany, were tested twice per week with a gargle pool rRT-PCR system from April to July of 2021. Infection chains of all 8 positive cases identified by school testing were followed up. RESULTS: In total, 8 positive cases were found by gargle pool PCR testing based on 96,764 school tests. While no transmissions occurred in the school setting, 20 of 27 household members of the 8 cases tested positive. The overall attack rate was 74.1% in families. CONCLUSIONS: No school outbreaks occurred during the study period. All cases but 1 were initially picked up by school testing. No transmission from school to families was observed.

Incidence of SARS-CoV-2 Infection among Healthcare Personnel after Restarting an Elective Cataract Surgery during the First COVID-19 Wave

Background: During the COVID-19 pandemic, most elective surgeries were postponed, including cataract surgery. However, patients with severe and disabling visual impairment may have required urgent correction. Objective: To report the incidence of SARS-CoV-2 infection among healthcare personnel working with the patients requiring cataract surgery, under a pre-operative screening protocol. Materials and Methods: A retrospective observational study was conducted in the Suddhavej Hospital, Mahasarakham University, Mahasarakham, Thailand during the early unlocked phase in May 2020. The local pre-operative screening protocol used during the period included questionnaires and pre-operative nucleic acid testing to screen for COVID-19 infection among patients. A combination of serial single nucleic acid test and SARSCoV-2 IgG antibody testing were used to screen SARS-CoV-2 infection among healthcare personnel. Mask wearing and physical distancing were required during hospitalization. Results: One hundred fifty-eight patients underwent cataract surgery under local anesthesia. Thirty-three healthcare personnel were included. All tests for SARS-CoV-2 were negative for both patients and healthcare personnel. The incidence rate of COVID-19 infection among healthcare personnel was 0 (95% CI 0.000 to 0.003) per 100 person-hours. There were no reported symptoms compatible with COVID-19 during the observed period and follow-up. Conclusion: Due to a very low incidence rate of hospital-acquired SARS-CoV-2 infection among healthcare personnel, elective cataract surgery under local anesthesia could be continued during COVID-19 pandemic with strict adherence to screening protocol and other preventive measures. SARS-CoV-2 screening method by questionnaire alone may be feasible in a low COVID-19 incidence rate. © 2022 JOURNAL OF THE MEDICAL ASSOCIATION OF THAILAND

Nucleic Acid and Immunological Diagnostics for SARS-CoV-2: Processes, Platforms and Pitfalls.

Accurate diagnosis at an early stage of infection is essential for the successful management of any contagious disease. The coronavirus disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus is a pandemic that has affected 214 countries affecting more than 37.4 million people causing 1.07 million deaths as of the second week of October 2020. The primary diagnosis of the infection is done either by the molecular technique of RT-qPCR by detecting portions of the RNA of the viral genome or through immunodiagnostic tests by detecting the viral proteins or the antibodies produced by the host. As the demand for the test increased rapidly many naive manufacturers entered the market with novel kits and more and more laboratories also entered the diagnostic arena making the test result more error-prone. There are serious debates globally and regionally on the sensitivity and specificity of these tests and about the overall accuracy and reliability of the tests for decision making on control strategies. The significance of the test is also complexed by the presence of asymptomatic carriers, re-occurrence of infection in cured patients as well as by the varied incubation periods of the infection and shifting of the viral location in the host tissues. In this paper, we review the techniques available for SARS-CoV-2 diagnosis and probable factors that can reduce the sensitivity and specificity of the different test methods currently in vogue. We also provide a checklist of factors to be considered to avoid fallacious practices to reduce false positive and false negative results by the clinical laboratories.