The application of sample pooling for mass screening of SARS-CoV-2 in an outbreak of COVID-19 in Vietnam

We sampled nasal–pharyngeal throat swabs from 96,123 asymptomatic individuals at risk of SARS-CoV-2 infection, and generated 22,290 pools at collection, each containing samples from two to seven individuals. We detected SARS-CoV-2 in 24 pools, and confirmed the infection in 32 individuals after resampling and testing of 104 samples from positive pools. We completed the testing within 14 days. We would have required 64 days to complete the screening for the same number of individuals if we had based our testing strategy on individual testing. There was no difference in cycle threshold (Ct) values of pooled and individual samples. Thus, compared with individual sample testing, our approach did not compromise PCR sensitivity, but saved 77% of the resources. The present strategy might be applicable in settings, where there are shortages of reagents and the disease prevalence is low, but the demand for testing is high

Human versus equine intramuscular antitoxin, with or without human intrathecal antitoxin, for the treatment of adults with tetanus: a 2x2 factorial randomized control trial

Background: Intramuscular antitoxin is recommended in tetanus treatment, but there are few data comparing human and equine preparations. As tetanus toxin acts within the central nervous system, where there is limited penetration of peripherally-administered antitoxin, intrathecal antitoxin administration may improve clinical outcomes compared to intramuscular injection. Methods: In a 2x2 factorial trial, adults with tetanus in a single-centre in Vietnam were randomized first to 3,000 IU human or 21,000 U equine intramuscular antitoxin, then to either 500 IU intrathecal human antitoxin or sham procedure. Interventions were delivered by independent clinicians, with attending clinicians and study staff blind to treatment allocations. The primary outcome was requirement for mechanical ventilation. Secondary outcomes included in-hospital mortality, death and disability at 240-days, duration of intensive care unit (ICU) stay, and adverse events. The study was registered at ClinicalTrials.gov, NCT 02999815 (status: recruitment completed). Findings: 272 adults were randomized. Mechanical ventilation was given to 56/130 (43%) of patients allocated to intrathecal antitoxin and 65/131 (50%) allocated to sham procedure (RR 0.87; 95% CI 0.66 to 1.13; p=0.29). For the intramuscular allocation 48/107 (45%), patients allocated to human antitoxin received mechanical ventilation compared to 48/108 (44%) patients allocated to equine antitoxin (relative risk (RR) 1.01, 95% confidence interval (CI) 0.75, 1.36, p=0.95). No clinically-relevant differences in secondary outcomes or adverse events were seen except for shorter length of ICU stay in those treated with intrathecal antitoxin compared to sham. Interpretation: We found no advantage of intramuscular human antitoxin over intramuscular equine antitoxin in tetanus treatment. Intrathecal antitoxin administration was safe but did not provide overall benefit in addition to intramuscular antitoxin administration. Funding: The Wellcome Trust, grant number 107367/Z/15/Z