SARS-CoV-2 in Africa.

The earliest cases of COVID-19 disease in Africa were, in most cases, the result of imports from abroad. The Democratic republic of the Congo (DRC) identified the first case at the beginning of 2020. Two days after his return from France, the first patient was tested positively in the capital, Kinshasa. The travel restrictions and status of the state of emergency were announced on 24 March 2020. A lockdown followed. In June of the same year, 11 provinces were already affected by COVID-19 disease. The negative socio-economic impact has occurred and is similar to that in any other country. The DRC does not differ from other African countries or on the issue of infectious diseases such as HIV, malaria, cholera, measles or Ebola virus disease. Recurring Ebola epidemics are addressed by vaccination with Ervebo vaccine. Unlike Ebola, part of the population does not believe in the existence of SARS-CoV-2 and does not respect basic anti-epidemic measures. Medical capacities were very limited at the beginning of the SARS-CoV-2 epidemic, both in terms of diagnosis and testing and availability of treatment (60 ventilators to 83 million inhabitants). The situation is complicated as a result of 20 years continuing wars. Another African country, Guinea, is currently facing not only COVID-19, but also the zoonotic disease of Lassa fever, which has been detected in several patients. Copyright © 2021, Medakta s.r.o.. All rights reserved.

Design of Replication-Competent VSV- and Ervebo-Vectored Vaccines Against SARS-CoV-2.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global public health emergency. Several vaccine candidates have been developed in response to the COVID-19 pandemic. One approach is to construct live-recombinant viruses expressing the SARS-CoV-2 spike protein (S) as vaccine candidates. The vesicular stomatitis virus (VSV) vector is a mature vaccine platform which was successfully developed as a vaccine against Ebola virus (EBOV), leading to its licensure by the Food and Drug Administration (FDA) in December 2019. Based on this work, we developed two live, replication-competent VSV-vectored vaccines against SARS-CoV-2: (1) a VSV expressing the S protein of SARS-CoV-2 and (2) a bivalent VSV expressing the S protein of SARS-CoV-2 and the glycoprotein (GP) of EBOV. This protocol describes the methodologies for the design, cloning, rescue, and preparation of these recombinant VSV vaccines.

Environmental Risk Assessment for rVSVΔG-ZEBOV-GP, a Genetically Modified Live Vaccine for Ebola Virus Disease.

rVSVΔG-ZEBOV-GP is a live, attenuated, recombinant vesicular stomatitis virus (rVSV)-based vaccine for the prevention of Ebola virus disease caused by Zaire ebolavirus. As a replication-competent genetically modified organism, rVSVΔG-ZEBOV-GP underwent various environmental evaluations prior to approval, the most in-depth being the environmental risk assessment (ERA) required by the European Medicines Agency. This ERA, as well as the underlying methodology used to arrive at a sound conclusion about the environmental risks of rVSVΔG-ZEBOV-GP, are described in this review. Clinical data from vaccinated adults demonstrated only infrequent, low-level shedding and transient, low-level viremia, indicating a low person-to-person infection risk. Animal data suggest that it is highly unlikely that vaccinated individuals would infect animals with recombinant virus vaccine or that rVSVΔG-ZEBOV-GP would spread within animal populations. Preclinical studies in various hematophagous insect vectors showed that these species were unable to transmit rVSVΔG-ZEBOV-GP. Pathogenicity risk in humans and animals was found to be low, based on clinical and preclinical data. The overall risk for non-vaccinated individuals and the environment is thus negligible and can be minimized further through defined mitigation strategies. This ERA and the experience gained are relevant to developing other rVSV-based vaccines, including candidates under investigation for prevention of COVID-19.