ABSTRACT
Messenger RNA (mRNA) vaccine has emerged as an attractive agent for prevention of infectious disease and anti-cancer therapy. However, there is a fatal risk that the safety evaluation for mRNA vaccine have not been fully studied yet. In this study, we evaluated the safety of four type of COVID-19 S-protein targeting mRNA vaccines with different compositions (C2/ LNP90, C2LNP128, C3LNP90 and C3LNP128). Theses vaccines were intramuscularly injected to 6-wk old male and female ICR mice with twice at an interval of 2 wks. The necropsy was carried out on 2 days or 14 days after secondary injection. The results showed that the body weight was decreased for 2days after the first injection in C2/LNP128 and C3/LNP128-injected mice, but it was almost recovered at 7day post injection (dpi). At 2 dpi after secondary injection, the endpoint blood analysis of demonstrated that C2/LNP128 and C3/LNP128 decreased the number of lymphocytes, monocytes and reticulocytes carrying the abnormal level of liver function indicator such as albumin, AST, ALT and total protein. Additionally, C2/LNP128 decreased the number of platelet and C3LNP128 decreased the number of red blood cells, respectably. Spleen and inguinal lymph node were enlarged in all experimental group. Notably, C2/LNP128 and C3/LNP128 induced severe edema in injection site, femoris muscle. At 14 dpi after secondary injection, the toxicity that was observed at 2 dpi after secondary injection was recovered. These results suggest that the potential side effects of mRNA vaccines must be systematically evaluated with multiple aspect of toxicology.
ABSTRACT
Middle East respiratory syndrome coronavirus (MERS-CoV) is an RNA virus that causes severe respiratory disease. Since it was identified in 2012, approximately 2500 MERS cases with high mortality have been confirmed in 27 countries. Although most cases have occurred in the Middle East, an outbreak in South Korea in 2015 showed that MERS could be a global threat via human-to-human transmission. There is no licensed vaccine against MERS. Thus, early detection is the best way to limit the spread of this fatal disease. In this review, we focus on transmission, the infection process, and scientific efforts in vaccine development and diagnostics for MERS-CoV. Keywords: Middle East respiratory syndrome coronavirus; epidemiology; virology; vaccine; diagnostics.