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Human Source SARS-CoV-2 Aerosol Transmission to Remote Sentinel Hamsters
Investigators used the South African Airborne Infections Research (AIR) facility near Pretoria to study human to animal (H2A) transmission of SARS-CoV-2 in newly diagnosed patients. Clinically confirmed COVID-19 patients were housed for up to four days in the AIR facility with continuously exhausting patient ward air to hamsters housed in animal exposure rooms. After a three- week exposure period, animals were held for an additional week to allow for antibody development. Animal sera were analyzed for anti-spike and plaque reduction activities and lung samples for pathology. Seven patients provided 400+ in-residence hours over a 17-day period. Pair-housed naïve golden Syrian hamsters (n=216) received continuous exposure to mixed patient-ward exhaust. Serum analyses revealed anti-SARS-CoV-2 IgG in 58% of animals tested. Plaque reduction assays on seven high titer sera revealed neutralizing activity. These results support the concept that viral bioaerosols generated from patients remain infectious over long-distance transport through a building ventilation system.
Nirmatrelvir–ritonavir versus Placebo–ritonavir in Individuals with Long COVID in the USA (PAX LC): A Double-blind, Randomized, Placebo-controlled, Phase 2, Decentralized Trial
Given that viral persistence has been hypothesized as a potential cause of Long COVID authors looked at whether antiviral therapy might provide a therapeutic benefit. In this phase 2, decentralized, double-blind, randomized controlled trial, adults (aged ≥18 years) from the 48 states across the contiguous USA, with previous documented SARS-CoV-2 infection and Long COVID symptoms starting within four weeks of initial infection and persisting for at least 12 weeks, were eligible for inclusion. Participants were randomly allocated to receive either two tablets of nirmatrelvir (150 mg each) and one tablet of ritonavir (100 mg), or placebo and one tablet of ritonavir (100 mg), orally administered twice daily for 15 days, stratified by age, sex at birth, and COVID-19 vaccination status. Between April 14, 2023, and Feb 26, 2024, 119 participants were screened. 100 were enrolled (66 [66%] female participants and 34 [34%] male participants), with 49 assigned to the nirmatrelvir–ritonavir group and 51 to the placebo–ritonavir group (intention-to-treat population). They found that nirmatrelvir–ritonavir administered for 15 days did not significantly improve health outcomes in participants with Long COVID compared with placebo–ritonavir at day 28.
Quantitative Brain Volume Differences Between COVID-19 Patients and Non-COVID-19 Volunteers: A Systematic Review
In this review, the majority of studies reported smaller grey matter volumes amongst COVID-19 patients compared to healthy volunteers, however, there were inconsistent findings, with three studies reporting larger grey matter volumes in the COVID-19 groups. Important context for these results is that studies with COVID-19 cohorts with more severe presentations, characterized by admission to the hospital or the ICU, were more likely to report smaller grey matter volumes compared to healthy volunteers, than studies that were focused on patients who recovered at home.
Donepezil for Fatigue and Psychological Symptoms in Post–COVID-19 Condition: A Randomized Clinical Trial
These results are from a randomized clinical trial of 110 patients, the baseline-adjusted estimating treatment effect of donepezil (Aricept-the minimally effective Alzheimer’s drug) on fatigue. They saw a minimal impact, which was not statistically significant. Secondary outcomes including depression, anxiety, and quality of life scores at three and eight weeks were also negative.
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COVID-19 in US and Canada
