Test-to-Stay After Exposure to SARS-CoV-2 in K-12 Schools

OBJECTIVES: We evaluated the safety and efficacy of a test-to-stay program for unvaccinated students and staff who experienced an unmasked, in-school exposure to someone with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Serial testing instead of quarantine was offered to asymptomatic contacts. We measured secondary and tertiary transmission rates within participating schools and in-school days preserved for participants. METHODS: Participating staff or students from universally masked districts in North Carolina underwent rapid antigen testing at set intervals up to 7 days after known exposure. Collected data included location or setting of exposure, participant symptoms, and school absences up to 14 days after enrollment. Outcomes included tertiary transmission, secondary transmission, and school days saved among test-to-stay participants. A prespecified interim safety analysis occurred after 1 month of enrollment. RESULTS: We enrolled 367 participants and completed 14-day follow-up on all participants for this analysis. Nearly all (215 of 238, 90%) exposure encounters involved an unmasked index case and an unmasked close contact, with most (353 of 366, 96%) occurring indoors, during lunch (137 of 357, 39%) or athletics (45 of 357, 13%). Secondary attack rate was 1.7% (95% confidence interval: 0.6%-4.7%) based on 883 SARS-CoV-2 serial rapid antigen tests with results from 357 participants; no tertiary cases were identified, and 1628 (92%) school days were saved through test-to-stay program implementation out of 1764 days potentially missed. CONCLUSION: After unmasked in-school exposure to SARS-CoV-2, even in a mostly unvaccinated population, a test-to-stay strategy is a safe alternative to quarantine

Combining Host-based and network-based intrusion detection system: A cost effective tool for managing intrusion detection

Intrusion detection has emerged as an important approach to data security. Current researches in areas of intrusion detection have tended towards network-based systems and how to improve on their intrusion detection. Only a little attention is given to host-based systems. For a thorough check on intrusion, both host-based and network-based systems should be involved to effectively detect attacks from insider as well as outsider sources. Installing separate systems, however, could be expensive. Some Intrusion detection System (IDS) vendors prefer to market them separately for some commercial gains. This study aims to integrate the advantages of both types of IDSs in a simple design that is cost effective. The proposed system uses its knowledge-based approach in the security log of the event log file in the Windows operating system to detect failed logins and unauthorized logins for the host-based IDS module while the network-based IDS module uses a hybrid  approach to detect attacks like land attack, syn flood, smurf, ping of death, and dictionary attacks. These attacks were simulated using hping. The proposed system is implemented in Java. The results show that the proposed system is able to detect attacks both from within (host-based) and outside sources (network-based).Key Words: Intrusion Detection System (IDS), Host-based, Network-based, Signature, Security log