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Global race for Marburg vaccine

Marburg virus, initially presenting as a cold before an explosion of symptoms, including organ failure and bleeding from multiple orifices, is spreading through Central Africa and causing panic among global health chiefs, who are racing to develop a vaccine for the virus.

An outbreak of the extremely deadly virus was declared in Equatorial Guinea last Monday after nine deaths and 16 suspected cases, and this past week, neighbouring Cameroon declared two suspected infections in a pair of teenagers with no travel links to Equatorial Guinea, indicating it is more widespread than official case counts suggest.

Marburg causes a haemorrhagic fever similar to Ebola. After incubating in the body for several days, if not weeks, it causes a devastating eruption of inflammation and blood clotting around the body that causes organs to stop working, reports Daily Mail.

The virus spreads when someone comes into contact with an infected person’s broken skin or mucous membranes in the eyes, nose, or mouth, and can take from two days to three weeks from exposure to the first appearance of symptoms, before a rapid and gory deterioration of health. This “incubation period” is where the virus has entered the body and begun to replicate, but has not yet caused symptoms.

When the virus enters the body, it targets immune cells, which protect the body from invaders like Marburg, and which then fail to properly activate white blood cells’ response to the virus, allowing it to spread further and evade natural protections.

Usually, around the fifth day, the patient starts bleeding from their eyes, with inflammation and swelling, often on the legs, ankles and feet.

Internal bleeding can cause discolouration of the skin, vomiting blood, dark and blood-coloured faeces, blood collection in the lungs and stomach and bleeding gums.

The fever remains high and some people have reported neurological symptoms like brain swelling, delirium, confusion, irritability and aggression.

Patients often die within eight or nine days of their first symptoms appearing, according to the WHO. The virus has an overall kill rate of around 50%, but up to 90% of patients die.

There are currently no vaccines or treatments approved to treat the virus.

On Tuesday, the WHO convened an urgent meeting of the Marburg virus vaccine consortium (MARVAC) to handle the outbreak.

The group said it could take months for effective vaccines and therapeutics to become available, as manufacturers would need to gather materials and perform trials, but experts told Daily Mail that a widely available effective treatment is actually “some years off”.

The MARVAC team has identified 28 experimental vaccine candidates that could be effective against the virus, most of which were developed to combat Ebola.

Five were highlighted in particular as vaccines to be explored.

Three vaccine developers – Janssen Pharmaceuticals, Public Health Vaccines and the Sabin Vaccine Institute – all non-profits, said they might be able to make doses available to test in the current outbreak.

The vaccines from Janssen and Sabin have already gone through phase one clinical trials. However, none of the vaccines is available in large quantities.

Public Health Vaccines’ jab was recently found to protect against the virus in monkeys, and the US Food and Drug Administration (FDA) has cleared it for human testing.

Little is known about other potential treatments that could help fend off infection, however.

Marburg is part of the Filoviridae family of viruses, believed to have been transmitted to humans from African fruit bats, with the first infected people exposed to the animals in mines and caves.

This is the first time Marburg has been detected in either Equatorial Guinea or Cameroon, signalling that the virus is spreading further into Africa.

It was first picked up in 1967, when workers were exposed to infected African green monkeys imported from Uganda to Germany and Serbia for experimentation.

Since then, outbreaks have occurred sporadically throughout sub-Saharan Africa, making its appearance in Central Africa a worrying sign. A total of 474 cases have been recorded.

All but 31, the initial outbreak in Europe, originated in Africa. Two cases from Uganda reached the Netherlands and United States in 2008.  Only nine cases have been recorded globally in the decade before the Equatorial Guinea outbreak.

 

Daily Mail article – Race against time for a vaccine for Marburg virus: Fears over stealthy disease that masquerades as a cold for days then suddenly causes organ failure and bleeding from multiple orifices – as outbreak in Africa spreads (Open access)

 

See more from MedicalBrief archives:

 

Equatorial Guinea confirms Marburg virus outbreak

 

First cases of deadly Marburg virus reported in Ghana

 

WHO confirms Marburg virus discovered for first time in West Africa

 

Zoonotic diseases: Sindbis, Langya and monkeypox outbreaks keep scientists on alert

 

 

 

 

 

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