COVID-19 active case findings based on self-collected saliva samples with CRISPR-Cas12a detection.

COVID-19 is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus affecting the world population. Early detection has become one of the most successful strategies to alleviate the epidemic and pandemic of this contagious coronavirus. Surveillance testing programs have been initiated in many countries worldwide to prevent the outbreak of COVID-19. In this study, we demonstrated that our previously established clustered regularly interspaced short palindromic repeats (CRISPR)-Cas12a-based assay could detect variants of concern during 2021 in Thailand, including Alpha, Beta, and Delta strains as well as Omicron strain in early 2022. In combination with the newly designed saliva collection funnel, we established a safe, simple, economical, and efficient self-collection protocol for the COVID-19 screening process. We successfully utilized the assay in an active case finding with a total number of 578 asymptomatic participants to detect the SARS-CoV-2 in saliva samples. We finally demonstrated that the validation and evaluation in a large-scale setting could provide valuable information and elaborate the practicality of the test in real-world settings. Our optimized protocol yielded effective results with high sensitivity, specificity, and diagnostic accuracy (96.86%). In addition, this study demonstrates COVID-19 active case findings in low-resource settings, which would be feasible and attractive for surveillance and outbreak prevention in the future.

Community-based surveillance contribution to the response of COVID-19 in Niger.

INTRODUCTION: the COVID-19 pandemic has spread across all countries in Africa, with much of the model forecasting disastrous results owing to weak health services and political uncertainty. In Niger, an adaptive solution to the COVID-19 pandemic has been implemented by community-based surveillance system (CBS) to complement passive case-finding in health systems. METHODS: the CBS program was designed to use the current CBS polio network spanning 37 health districts in six regions. Between April and November 2020, 150 community health workers (CHWs) were equipped to improve integrated disease surveillance and response (IDSR) preparedness and response to the COVID-19 pandemic. We retrospectively analysed the health data of the National Health Information System to describe the effect of CBS in COVID-19 surveillance. RESULTS: overall, trained CHWs were able to raise awareness among 2,681,642 persons regarding COVID-19 preventions and controls strategies. They reported 143 (84%) valid alerts resulting in two positive COVID-19 cases missing in the community. In addition, CHWs added to the contact tracing of 37 individuals and informed about the deaths in the community. CONCLUSION: community-based surveillance improved COVID-19 response in Niger. Logistic assistance and ongoing training are the foundations for increasing and sustaining the sensitivity of CBS systems in response to the COVID-19 pandemic to deter hotspots across countries.