COVID 19 breakthrough infection risk: a simple physical model describing the dependence on antibody concentration

The increase of COVID-19 breakthrough infection risk with time since vaccination has a clear relationship to the decrease of antibody concentration with time. The empirically-observed dependence on blood IgG anti-receptor binding domain antibody concentration of SARS-CoV-2 vaccine efficacy against infection has a rational explanation in the statistics of binding of antibody to spike proteins on the virus surface, leading to blocking of binding to the receptor: namely that the probability of infection is the probability that a critical number of the spike proteins protruding from the virus are unblocked. The model is consistent with the observed antibody concentrations required to induce immunity and with the observed dependence of vaccine efficacy on antibody concentration and thus is a useful tool in the development of models to relate, for an individual person, risk of infection given measured antibody concentration. It can be used to relate population breakthrough infection risk to the distribution across the population of antibody concentration, and its variation with time.

The failure of private health services: COVID-19 induced crises in low- and middle-income country (LMIC) health systems.

For decades, governments and development partners promoted neoliberal policies in the health sector in many LMICs, largely motivated by the belief that governments in these countries were too weak to provide all the health services necessary to meet population needs. Private health markets became the governance and policy solution to improve the delivery of health services which allowed embedded forms of market failure to persist in these countries and which were exposed during the COVID-19 pandemic. In this article, we analyse the manifestations of these market failures using data from an assembled database of COVID-19 related news items sourced from the Global Database of Events, Language, and Tone. Specifically, we identify how pre-existing market failure and failures of redistribution have led to the rise of three urgent crises in LMICs: a financial and liquidity crisis among private providers, a crisis of service provision and pricing, and an attendant crisis in state-provider relations. The COVID-19 pandemic has therfore exposed important failures of the public-private models of health systems and provides an opportunity to rethink the future orientation of national health systems and commitments towards Universal Health Coverage.

Validation and testing of a method for detection of SARS-CoV-2 RNA in healthy human stool

Summary (Abstract)O_ST_ABSBackgroundC_ST_ABSFecal shedding of SARS-CoV-2 has raised concerns about transmission through fecal microbiota transplantation (FMT) procedures. While many tests have been authorized for diagnosis of COVID-19 using respiratory samples, no fully validated stool tests for detection of SARS-CoV-2 are currently available. We sought to adapt and validate an available test specifically for detection of SARS-CoV-2 in human stool. MethodsStool samples were spiked with inactivated SAR-CoV-2 virus for development and validation of the assay. A modified version of the CDC rRT-PCR SARS-CoV-2 test was used for detection of virus. Analytical sensitivity, assay reproducibility, and sample stability under a variety of storage conditions were assessed. We also performed the assay on stool samples collected from known COVID positive individuals. FindingsThe lower limit of detection (LoD) of the assay was found to be 3000 viral RNA copies per gram of original stool sample, with 100% detection across 20 replicates assessed at this concentration. Samples were relatively stable in all buffers tested at both 4{degrees}C and ambient temperature, with the exception of storage in STAR buffer at ambient temperature. Assay sensitivity was slightly diminished in low-copy-number samples after a single freeze-thaw cycle at -80{degrees}C. Thirty contrived SARS-CoV-2 samples were tested by a second laboratory and were correctly identified as positive or negative in at least one of two rounds of testing. Additionally, we detected SARS-CoV-2 RNA in the stool of known COVID-19 positive individuals using this method. InterpretationThis is a sensitive, reproducible, and validated assay for detection of SARS-CoV-2 RNA in human stool with potential uses in FMT donor screening, sewage monitoring, and further research into the impact of fecal shedding on the epidemiology of this pandemic. FundingNational Institute for Allergy and Infectious Diseases, NIH. Center for Biologics Evaluation and Research, FDA. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSSince the onset of the COVID-19 pandemic, multiple studies have documented shedding of SARS-CoV-2 RNA in feces and considered the potential for fecal-oral transmission of this virus. This potential risk led to the U.S. Food and Drug Administration issuing a safety alert that contained the recommendation that no stool donated after December 1, 2019 be used for manufacture of Fecal Microbiota for Transplantation (FMT) products in the United States until such a time as sufficient screening procedures could be put in place to mitigate this risk. Added value of this studyHere, we report the development and validation of an assay specifically meant for the detection of SARS-CoV-2 RNA in the stool of healthy individuals. While studies have reported detection of viral RNA in stool previously, this is the first publication of a validated assay designed for this purpose. Implications of all the available evidenceThe work presented here provides a validated SARS-CoV-2 stool assay with potential application to FMT donor screening protocols, sewage monitoring protocols, as well as research studies assessing the role of stool shedding and transmission on the epidemiology of COVID-19.

The First Meeting of the National Control Laboratories for Vaccines and Biologicals in the Western Pacific in 2016

The first meeting of the National Control Laboratories for Vaccines and Biologicals in the Western Pacific Region was held on September 1–2, 2016 in Seoul, the Republic of Korea. The meeting objectives were to share results of current research and to promote collaboration between the National Control Laboratories. To this end, we first discussed each country’s current status of research on quality control of biologicals. Next, we reviewed quality control of snake venom and antivenom production and the progress of a collaborative study on the Korean reference standard candidate for snake venom. We also discussed the establishment of the second regional reference standard antivenom and the characterization of the Vero cell genome landscape and its application to quality control. Moreover, we also reflected on the importance of collaboration among interested parties participating in this meeting. In conclusion, the meeting initiated networking between the national control laboratories in the Western Pacific region and paved the way to continue collaboration, which will eventually improve the region’s capacity for quality control of biologicals.