Successful MERS Vaccine In Mice May Hold Promise For COVID-19 Vaccine

Vaccine research to vanquish the horrendous and deadly viruses may occasionally hold positive surprises for scientists and their fans. A team of researchers at the University of Iowa and the University of Georgia, USA have developed a vaccine that fully protects mice against a lethal dose of MERS, a notorious, close cousin of SARS-COV2 that causes COVID-19. Surprisingly, they found that their MERS vaccine also holds promise for developing vaccines against other coronaviruses diseases, including COVID-19, which at present holds many nations including India to ransom.

 Use of PIV5, an innocuous virus

Their vaccine is a parainfluenza virus (PIV5) carrying the “spike” protein that MERS uses to infect cells. Researchers showed that all the vaccinated mice survived a lethal dose of the MERS coronavirus. mBio, the Journal of the American Society for Microbiology published the results of the study on April 7, 2020.

 “PIV5 is an excellent viral vector candidate for vaccine development; it is safe and infects a large number of mammals without being associated with any diseases, except kennel cough in dogs,” the researchers clarified.

The team led by Paul McCray at the UI Carver College of Medicine, and Biao He, at the University Of Georgia College Of Veterinary Medicine, tested a MERS vaccine candidate in mice engineered to be susceptible to the MERS coronavirus and found that just one, relatively low dose of the vaccine given to the mice intra-nasally (inhaled through the nose) was sufficient to protect fully all the treated mice from a lethal dose of MERS coronavirus.

“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,” says McCray, UI professor of paediatrics in a press release from the University of Iowa Health Care.

Some questions and answers

“Can you comment on the way the vaccine may be applied to persons and advantages if any, for accepting the method?

“The idea is to use this as a topical mucosal vaccine, similar to how the influenza vaccine FluMist is delivered. It may be advantageous to immunize this way for a respiratory pathogen like SARS-CoV-2,” Professor Paul McCray responded to my e-mail query.

“How stable is the vaccine at different temperatures?”

“This is a very good question.  PIV5 is used in vaccines for kennel cough.  We know that kennel cough vaccines can be stored in refrigerators for over 1 year. At -80 degrees, we can keep PIV5 stable for over 5 years. Currently, we are investigating storage at room temperature,” he replied.

To the question on the effectiveness of the vaccine for different age groups, Professor McCray conceded that they have not tested PIV5 vaccine in humans yet. 

“We expect it to be effective in both young and old,” McCray added.

 “How long it may take for getting the vaccine ready for use?”

“We have made a PIV5-based COVID-19 vaccine. We are testing it in different animal species right now. Based on experience we have had with other PIV5-based vaccines such as a PIV5-based RSV vaccine, we expect that PIV5-COVID-19 will perform well in non-human primates. Dr. He’s group is working on preparing a GMP lot of PIV5-COVID-19 vaccine, which is required for testing in humans, by the end of summer,” McCray said.  

McCray noted that, “The overall goal is to test this vaccine in humans as soon as FDA approves. It is possible that if there is FDA approval a trial could happen by the fall of 2020.  An advantage of this vaccine strategy is that it is likely that a small dose is sufficient for protection. This could help simplify production issues”.

McCray confidently drew the expected time line. Regulatory agencies are also changing their rigid stands. It may fast-forward such projects.

Humanity quickly needs an effective drug and an efficacious vaccine against the COVID 19 virus. A recent review published by the Coalition for Epidemic Preparedness Innovations (CEPI) in journal Nature noted that the publication of the genetic sequence of the coronavirus that causes COVID-19 triggered  intense global R&D activity to develop a vaccine against the disease. The CEPI found that as of 8 April 2020, this vaccine field includes 115 vaccine candidates. Five of the most advanced among them have entered human trial.  

According to the CEPI, “the current response to the coronavirus disease 2019 (COVID-19) pandemic involves aggressive implementation of suppression strategies, such as case identification, quarantine and isolation, contact tracing, and social distancing. However, models developed by the Imperial College COVID-19 Response Team suggest that “transmission will quickly rebound if interventions are relaxed”. The coalition asserted that   the development of COVID-19 vaccines that can be used globally is a priority for ending the pandemic.