The Middle East Respiratory Syndrome (MERS)-related coronavirus was first identified in 2012 and the World Health Organization (WHO) lists MERS as a pathogen that is considered of particular threat to the public health. MERS is transmitted by camel-human or human-human contact and can have a mortality rate as high as 35%. It was first reported in Saudi Arabia but has spread to 27 other countries, with almost 2,500 cases reported worldwide. Currently, there is still no vaccine or treatment drug for MERS.
Being able to develop a MERS vaccine could help with the development of a vaccine for the novel coronavirus (SARS-CoV-2). Says Marylyn Addo, Head of the Division of Infectious Diseases at the UKE and scientist at the German Center for Infection Research (DZIF), "In 2014, together with DZIF partners, we started to develop a vaccine against the MERS coronavirus in preparation for larger outbreaks of the virus in the future. The results of this vaccine trial are also important and promising regarding the development of a vaccine against SARS-CoV-2, the new coronavirus. The development of the MERS vaccine provides a basis upon which we at the DZIF can rapidly develop a vaccine against the new coronavirus."
The vaccine trial sampled 23 healthy volunteers who were vaccinated twice with the experimental vaccine (MVA-MERS-S), with four weeks between vaccinations. The vaccine trial set out to answer two questions: is it well-tolerated and safe for humans and does it trigger the development of MERS-CoV antibodies?
The results of the trial were positive; the vaccine was well-tolerated with no severe side effects. One of the first authors of the vaccine trial, Dr. Till Koch, commented, “The tolerability and safety of the vaccine candidate as well as the resulting immune responses are very promising.”
"After the second injection of MVA-MERS-S, antibody formation and T cell responses occurred in 87 percent of the trial subjects," says first co-author Dr. Christine Dahlke.
The next step is a phase 1b trial, which will test the vaccine in 160 participants. If this trial is also successful, the scientists will then try to use the same viral vector (MVA) and then will insert the SARS-CoV-2 spike protein in place of the MERS-CoV spike protein to see if this can also be used as a vaccine for the novel coronavirus. The results of the trial are published in the journal, The Lancet.