Vaccine against the MERS coronavirus tested as safe and effective in phase Ib clinical trial

The MERS coronavirus—MERS stands for “Middle East respiratory syndrome”—causes severe respiratory diseases with a high mortality rate. To date, there is neither a vaccine nor a specific treatment. The safety, immunogenicity and optimal dosing regimen of the MVA-MERS-S vaccine candidate developed at the DZIF have now been investigated in a phase Ib study in healthy individuals who were previously infected with the related coronavirus SARS-CoV-2.

The study, led by Prof Marylyn Addo at the University Medical Center Hamburg-Eppendorf and published in The Lancet Infectious Diseases, has shown that the vaccine is safe and effective. Further studies on the safety and efficacy of the vaccine in risk groups for severe MERS-CoV disease, including the elderly and people with relevant comorbidities, will follow.

First identified in the Middle East in 2012, the MERS coronavirus is transmitted from dromedaries to humans by droplet infection and can also be passed from person to person. The pathogen causes severe respiratory diseases, which are fatal in up to 36% of cases. The MERS coronavirus has been classified by the World Health Organization (WHO) as particularly dangerous to public health. To date, more than 2,600 cases of MERS have been confirmed in 27 countries worldwide, with a focus on Saudi Arabia. To date, there is no effective vaccine and no specific treatment.

The MVA-MERS-S vaccine candidate developed at the German Center for Infection Research (DZIF) since 2013 is based on an attenuated virus—the so-called “Modified Vaccinia Ankara Virus” (MVA)—which has been supplemented with protein components of the MERS virus. The results of the Phase 1B trial show that the vaccine is effective and safe, even in people with a previous or simultaneous infection with the COVID-19 pathogen SARS-CoV-2.

Two vaccine doses and two different vaccination intervals were investigated in the placebo-controlled and randomized double-blind study. The 140 test subjects experienced isolated local reactions such as slight pain at the injection site, but no serious vaccine-related side effects.

“Further studies are now needed, including to verify these results in risk groups for severe MERS-CoV disease such as the elderly and people with relevant comorbidities,” says Prof Addo, who is director of the Institute for Infection Research and Vaccine Development at the UKE and coordinator of the DZIF research area Emerging Infections.

Provided by
Deutsches Zentrum für Infektionsforschung