Assessment of the efficacy of SARS-CoV-2 vaccines in non-human primate studies - a systematic review

Abstract

The outbreak of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggered the rapid and successful development of vaccines to help mitigate the effect of the coronavirus disease 2019 (COVID-19) and circulation of the virus. Preclinical vaccine trials provide a wealth of information about the presence and persistence of virus in different anatomical sites. We systematically reviewed all available preclinical SARS-CoV-2 candidate vaccine studies where non-human primates were challenged after vaccination. We found marked heterogeneity in experimental design between the studies. Most of the tested vaccines, only triggered a low or moderate reduction of viral RNA in the upper respiratory tract; We need to consider that most SARS-CoV-2 vaccines that protect against disease might not fully protect against infectiousness and vaccinated individuals might still contribute to SARS-CoV-2 transmission. Careful assessment of secondary attack rates from vaccinated individuals is warranted. Standardization in design and reporting of preclinical trials is necessary.