Induction of Cross-Reacting Antibodies Against the COVID-19 by BCG Vaccination in the Mouse Model.

It was reported that tuberculosis and BCG vaccination are potential tools for reducing the burden of COVID-19, mainly through the non-specific trained immunity. We have investigated whether BCG vaccination is able to induce cross-reacting antibodies against the SARS-CoV-2. We have tested the induced humoral immune responses against the SARS-CoV-2 Spike in the mouse model, after either BCG or rabies DNA-based vaccination alone or in Prime/Boost approach to COVID-19 DNA-based vaccination. We have demonstrated that BCG vaccination alone was able to induce cross-reacting antibodies to SARS-CoV-2 Spike. It can also boost the antibody response induced by a COVID-19 DNA-based vaccination. Hence, both BCG and latent tuberculosis infection can explain the lower burden of COVID-19 in developing countries, not only through the trained immunity but also by inducing cross-reacting antibodies. Furthermore, with the emergence of different COVID-19 variants, or eventually other Betacoronaviruses, the use of BCG vaccination can help against immune escapes of the current vaccines.

Genetic characterization and phylogenetic analysis of rabbit hemorrhagic disease virus isolated in Tunisia from 2015 to 2018.

Two distinct genotypes responsible for rabbit hemorrhagic disease (RHD) are reported, GI.1 (RHDV) and GI.2 (RHDV2). Vaccines based on these two genotypes are only partially cross-protective. Hence, knowing which genotype is circulating is important for appropriate control measures. We have investigated 25 field samples isolated between 2015 and 2018 from rabbits with clinical signs of RHD. Only GI.2 (RHDV2) is currently circulating in Tunisia. All Tunisian samples were grouped together with typical genotypic and phenotypic mutations. Therefore, we recommend initiating an extensive preventive vaccination program based on GI.2 vaccines in addition to a regular monitoring of the circulating lagoviruses.