Abstract: Rapid increase of SpO2 on room air for 34 severe COVID-19 patients after ivermectin-based combination treatment: 55-62% normalization within 12-24 hours Jacqueline C Stone College of Primary Care Physicians of Zimbabwe, Harare, Zimbabwe Pisirai Ndarukwa National Coordinator Ivermectin Research (MoHCC), Harare, Zimbabwe David E Scheim (  dscheim@alum.mit.edu ) US Public Health Service, Commissioned Corps, Inactive Reserve, Blacksburg, VA, US https://orcid.org/0000-0001-6841-7054 Barry M Dancis Independent bioinformatics consultant, Silver Spring, MD, US Jerry Dancis Department of Mathematics, University of Maryland, College Park, MD, US Martin G Gill ENT Surgeon, Private Practice, Fourways Life Hospital, Gauteng, South Africa Colleen Aldous College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa https://orcid.org/0000-00027199-9160 Research Article Keywords: COVID-19, SARS-CoV-2, spike protein, ivermectin, doxycycline, SpO2 Posted Date: November 9th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-1048271/v1 License:   This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/21 Abstract Background. The emergence of COVID-19 in March 2020 challenged Zimbabwe to mount a response with limited medical facilities and therapeutic options. Ivermectin (IVM) had by then been safely used to treat a variety of human diseases affecting millions, as noted by the Nobel Committee in awarding its 2015 prize for medicine. Based upon early clinical indications of efficacy against COVID-19, IVM-based combination treatments were deployed to treat this infection in Zimbabwe. Methods. Data were retrospectively analyzed for 34 severe COVID-19 patients treated with IVM-based combination therapy between August 2020 and May 2021, for whom pre- and post-treatment SpO2 values were all recorded on room air. Mortality and deterioration outcomes were also analyzed for a larger set of 92 severe COVID-19 patients receiving IVM-based treatment. Results: For the 34-patient SpO2 tracking series, all but two patients had significantly increased SpO2 values after the first IVM dose, and all patients recovered. Mean increases in SpO2 as percentages of full normalization to SpO2=97 were 55.1% at +12 hours and 62.3% at +24 hours post-treatment. These results paralleled similar sharp increases in SpO2, all on room air, for a series of 24 RT-qPCR confirmed, mostly severe COVID-19 patients in the USA (California) who were given IVM combination treatment, all of whom recovered. For 19 of those patients having SpO2 ≤ 90 prior to IVM, the mean SpO2 normalization at +24 hours posttreatment was 65.2% as calculated from the SpO2 values reported. For our larger series of 92 severe COVID-19 patients in Zimbabwe, median age 53, only two died and two more deteriorated prior to recovery, far less than a predicted 7 deaths and 17 deteriorations for the demographics and risk factors of these patients. Conclusions. The rapid, marked increases in SpO2 for both the Zimbabwe and California patients stand in sharp contrast to the decline in SpO2 and associated pulmonary function following onset of moderate or severe COVID-19 symptoms under standard care. These rapid SpO2 increases and low mortality rates support extended deployment of IVM treatment for COVID-19, complementary to immunizations for prevention. Background Evaluations of efficacy for COVID-19 therapeutics are challenging since most patients with this..