Authors: Lauren Woolfe, Future Science Group
Research conducted at the University of Iowa (IA, USA) and the University of Georgia (GA, USA) has demonstrated a novel vaccine to be successful in protecting mice against a lethal dose of MERS. The results, published in mBio, hold implications for the development of a vaccine for COVID-19.
SARS-Cov-2, the causative agent for COVID-19, is closely related to MERS, a virus that is fatal in approximately one third of known cases, making it more deadly than SARS-CoV-2; however, only 2494 cases have been reported since 2012.
The vaccine tested in this study is an innocuous parainfluenza virus (PIV5) carrying a ‘spike protein,’ which MERS uses to infect cells. Recent studies have also revealed that it is this same mechanism employed in human cell invasion by SARS-CoV-2.
Mice were vaccinated intranasally with a relatively low dose. When challenged with a lethal dose of MERS, they all survived.
Upon analyzing the immune responses, the researchers discovered that both antibody and protective T cells were produced. However, these responses were weak, leading the team to speculate that this may be due to the T cell response in the mouse lungs.
The researchers explained that PIV5 expressing a coronavirus spike protein is an excellent candidate for future vaccine development due to parainfluenza virus’ ability to infect a multitude of mammalian hosts, along with the sufficiency of a low vaccine dose to prevent infection, which makes it ideal for creation on a mass scale.
The vaccine used in this study was the most effective MERS vaccine to date in animal models of the disease, and is currently being investigated for use in other respiratory diseases, such as respiratory syncytial virus, suggesting that this development could be utilized in the creation of a vaccine against SARS-CoV-2.
“Our new study indicates that PIV5 may be a useful vaccine platform for emerging coronavirus diseases, including SARS-CoV-2, the virus causing the ongoing COVID-19 pandemic” commented lead author Paul McCray (University of Iowa). “Using the same strategy, vaccine candidates based on PIV5 expressing the spike protein of SARS-CoV-2 have been generated. We are planning more studies in animals to test the ability of PIV5-based vaccines in preventing disease caused by SARS-CoV-2.”