New Marburg outbreak sparks race to test vaccines

Equatorial Guinea announced its first outbreak of the highly-infectious Marburg disease — a hemorrhagic fever similar to Ebola. The disease has a fatality rate that can reach 88%. The virus spills over from fruit bats to humans, and once transferred can spread between people through bodily fluids with the virus able to persist for several days on surfaces. The last outbreak of Marburg ended last September in Ghana, with three confirmed cases. There are no vaccines or antiviral treatments approved for the virus, but there are candidates. Researchers held an emergency meeting on Tuesday to examine the prospect for quickly rolling out clinical trials during the current outbreak. A district health officer in Equatorial Guinea raised the alarm of the disease on Feb. 7, after which test samples were sent to a reference laboratory at Institut Pasteur in Senegal to confirm the outbreak. Nine deaths and 16 suspected cases of the virus have been reported in the western province of Kié Ntem, which borders on Cameroon and Gabon. The suspected cases are in quarantine. George Ameh, the World Health Organization representative to Equatorial Guinea, said during the emergency meeting the cases are close family members that attended burials — an event that can spread the virus. There are 15 asymptomatic contacts being held at home. Teams have been deployed for contact tracing of cases and to provide medical care. During the emergency meeting members of the Marburg Virus Vaccine Consortium — a WHO-led group working to increase international collaboration around the development of a vaccine — discussed the possibility of hosting clinical trials during this outbreak. Members of the consortium stressed the need for speed — in the recent Ebola outbreak in Uganda, efforts to start clinical trials for vaccines for the rare Sudan strain of the virus took longer than the outbreak lasted, preventing researchers from collecting data. William Dowling, head of preclinical development at the Coalition for Epidemic Preparedness, or CEPI, said he is aware of two candidate vaccines to counter Marburg that have phase 1 clinical trial data — one developed by Sabin Vaccine Institute and the other by Janssen. Three other candidates are yet to reach the completion of phase 1 clinical trials. A key purpose of the meeting was to determine how many vials of vaccine candidates are available for use and if they have bulk material that could be put into vials quickly. Representatives from Janssen said thousands of candidate vaccine doses might be available but additional stability testing was needed. Other developers reported smaller batches. “Having doses available in vials is going to be a critical element of being able to do investigations in outbreaks,” said Phil Krause, chair of WHO’s COVID-19 Vaccines Research Expert Group. There are also no existing therapeutics for Marburg, but there are candidates for therapeutics which could also be tested in clinical trials during this outbreak. Krause said combining some of these candidate therapeutics together may be more effective than using any individual therapeutic as a sole treatment. Currently, health workers rehydrate Marburg patients with oral and intravenous fluids to increase their chances of survival.