Priority diseases

Vaccines can help prevent disease outbreaks from becoming humanitarian crises. CEPI supports the development of vaccines against deadly diseases for which no licenced vaccines are currently available.

Targeting diseases with epidemic potential

CEPI has announced three calls for proposals inviting applicants to submit funding proposals to develop specific vaccine candidates or research that can directly support development of vaccines against our priority pathogens.


The first call supports candidate vaccines against MERS-CoV, Nipah virus, and Lassa virus. These diseases were chosen from a priority list established by the WHO in its R&D Blueprint for Action to Prevent Epidemics.


The second call supports the advancement of rapid-response platforms against unknown pathogens (also referred to as Disease X). Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease. In the WHO R&D Blueprint, it explicitly seeks to enable cross-cutting R&D preparedness that is also relevant for an unknown “Disease X” as far as possible.


Our third call will support vaccines against Rift Valley fever and Chikungunya viruses. Rift Valley fever has been listed in the WHO R&D Blueprint of priority pathogens in view of its epidemic potential. The WHO has also highlighted Chikungunya as a major public health risk and has stated that further research and development is needed to mitigate the risk it poses.

MERS-CoVLassaNipahDisease XRift Valley feverChikungunya Test
Disease X
Rift Valley fever

Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

What is it?

MERS-CoV is the virus that causes Middle East respiratory syndrome (MERS). It is a coronavirus, part of the same family of viruses that causes the common cold and SARS (severe acute respiratory syndrome). MERS is a zoonotic disease, meaning it passes from animals to humans. It’s thought that camels are a major source of infection in people. Raising camels, eating undercooked camel meat, and drinking raw camel milk or urine are risk factors for the disease in humans. MERS-CoV can spread from person to person, usually through close contact.

Where does it occur?

The disease was first reported in Saudi Arabia in 2012, and most reported cases have been linked to countries in and around the Arabian Peninsula.


According to WHO, from 2012 through 16 September 2018, the total global number of laboratory-confirmed MERS cases reported to WHO is 2254, with 800 associated deaths.


In 2015, a large outbreak occurred in South Korea, following a single “super-spreader” transmitting the virus to 82 people in three days.


More recently, from 1 June 2018 athrough to 16 September 2018, the International Health Regulations (IHR 2005) National Focal Point of Saudi Arabia reported 32 additional cases of MERS, including 10 deaths. Cases have also been recently reported in South Korea and the UK.

Who does it affect?

MERS-CoV can infect people of any age. It causes a severe acute respiratory illness with fever, cough and shortness of breath. Gastrointestinal symptoms can also occur. Around 36% of people reported as having MERS have died, many of whom already had an underlying medical condition. There is no specific antiviral treatment for MERS-CoV infection.


How do we currently prevent infections?

People are advised to try and prevent getting infected by avoiding undercooked or raw camel products, and by being hygienic, especially around animals. There is currently no vaccine against MERS-CoV.

Lassa virus

What is it?

Lassa virus belongs to the Arenaviridae family and causes Lassa fever, also known as Lassa haemorrhagic fever (LHF). It is a haemorrhagic illness that occurs between one and three weeks after infection.


Lassa fever is a zoonotic disease, meaning it passes from animals to humans. The natural host of Lassa virus is the rodent Mastomys natalensis, otherwise known as the Natal multimammate mouse or rat.


The virus is spread when a person comes into contact with items contaminated with the rodent’s urine or faeces – for example, by handling objects, eating, or through open wounds. It can also be inhaled.


Lassa virus can pass from person to person via bodily fluids, and can spread in healthcare settings if suitable precautions are not taken.


Where does it occur?

Lassa virus was identified in 1969 after the death of two missionary nuns in Nigeria. Lassa fever occurs regularly in parts of West Africa, including, Sierra Leone, Nigeria, Guinea, Liberia, Mali Benin and Ghana. It causes more than 300,000 cases of illness and 3000 deaths each year.


Various outbreaks were reported in West Africa in 2016. In March 2016, a healthcare worker evacuated from Togo to Germany died and was subsequently diagnosed with Lassa fever. A funeral home employee who handled the corpse then contracted the disease, but recovered. In Sweden, a 72-year-old woman was diagnosed with Lassa fever following a six-week trip to Liberia. She was later discharged.


In 2018, Nigeria experienced an unusually large increase in Lassa fever cases which led the WHO to declare it an outbreak. A recent study identified that the spread of disease during this outbreak was largely a result of ongoing cross-species transmission from local rodent populations, rather than via human-human transmission.


What does it do?

Around 80 per cent of patients with Lassa fever have no symptoms. Those that do can experience mild fever or headache. More serious symptoms include: vomiting, swelling of the face, pain in the chest, back and abdomen, and bleeding from body parts, including the eyes and nose.


Patients can be given rehydration therapy and supportive care. An antiviral drug ribavirin has been used successfully in some cases.


One per cent of infections are fatal, usually within two weeks of symptoms beginning. Around 15 to 20 per cent of people hospitalised with Lassa fever die from it. A common complication in survivors of Lassa fever is hearing loss.


How do we currently prevent infections?

People are advised to avoid contact with Mastomys rodents, including by keeping homes clean and storing food away from rodents. Healthcare workers should follow specific infection control methods. There is currently no vaccine against Lassa virus.

Image Cred

Nipah virus

What is it?

Nipah virus belongs to the Paramyxoviridae family of viruses, genus Henipavirus, alongside Hendra virus. Nipah is a zoonotic disease, meaning it passes from animals to humans.


The natural hosts of the virus are fruit bats (also known as flying foxes) of the genus Pteropus. Nipah virus can be spread to people from infected bats, infected pigs, or infected people.


Where does it occur?

Nipah virus was first identified in 1999 during an outbreak of illness affecting pig farmers and others having close contact with pigs in Malaysia and Singapore. Over 100 human deaths were reported, and over a million pigs were killed in the effort to stop the outbreak. No cases of person-to-person spread were reported. In 2001, there was an outbreak of Nipah virus in people in Bangladesh, and a separate outbreak in a hospital in India. In both countries, person-to-person transmission occurred. Since then, Bangladesh has suffered outbreaks nearly every year – with over 300 confirmed cases occurring there from 2001 to 2015.


India has also occasionally reported cases and experienced an outbreak in the southern State of Kerala earlier this year. A total of 19 Nipah virus cases, including 17 deaths, were reported from Kerala State. Those who died included a nurse who had been caring for a patient ill with Nipah virus disease. More than 2500 contacts of Nipah patients were monitored by the state surveillance system and a 24-hour helpline took queries from the community. By mid-June, the Kerala government and the Union Health Ministry announced that the outbreak had been contained.


So far, Nipah outbreaks have been confined to South and Southeast Asia, but Pteropus bats are found in a large geographical area across the globe covering a population of more than 2 billion people. A spread of the virus among these bat populations could put a huge number of people worldwide at risk of zoonotic infection. Furthermore, as the virus is capable of person-to-person spread, in theory a Nipah-infected individual could bring the virus even to regions where Pteropus bats do not live and infect others in those regions. Thus, Nipah virus has the biological potential to be a truly global threat.


What does it do?

Nipah virus infection can cause severe, rapidly progressive illness that affects the respiratory system and the central nervous system, including inflammation of the brain (encephalitis). Symptoms begin between 5 and 14 days after infection, and include fever, altered mental state, cough and respiratory problems.


How do we currently prevent infections?

People are advised to avoid contact with ill pigs and bats in countries where Nipah virus is known to occur. They are also advised to avoid drinking raw date palm sap, which can be infected with bodily fluids from bats.


There are currently no vaccines or specific therapeutics against Nipah virus approved for use in humans.

Disease X

What is it?

“Disease X” represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease. In February 2018, Disease X was included in the updated WHO R&D Blueprint list of priority diseases.


By their very nature, we cannot predict what or where “Disease X” is likely to emerge.


What we do know is that new diseases emerge all the time, from locations all around the world. Developing countries, particularly those with high rates of biodiversity, are at heightened risk, because of the increased risk of outbreaks and the limited capacity for surveillance and response in these countries.


Because epidemic diseases do not respect borders, we need to be prepared on a global scale to respond to dangerous outbreaks anywhere.


Preparing for Disease X

To help the world quickly respond to Disease X, CEPI is funding the development of new vaccine platform technologies so that we can rapidly manufacture vaccines against many different types of disease.

Historically, vaccine development has been a long, risky, and costly endeavour, taking years or even decades to test the safety and efficacy of a vaccine in humans. The idea with platform technologies is that the process for developing a new vaccine is worked out in advance, fast-tracking its production for use against a new disease. If we can hone these technologies and refine the platform manufacturing approach, we could create vaccines against epidemic infectious diseases ‘just-in-time’, within weeks instead of years, enabling the world to respond quickly and control epidemic threats.

Rift Valley fever


Rift Valley fever has been listed in the WHO R&D Blueprint of priority pathogens in view of its epidemic potential.


The virus—a member of the Phlebovirus genus—is transmitted by mosquitoes and blood feeding flies that usually affects animals (commonly cattle and sheep) but can also involve humans.


Most human infections result from contact with the blood or organs of infected animals but can also result from the bites of infected mosquitoes. The virus was first identified in 1931 during an investigation into an epidemic among sheep on a farm in the Rift Valley of Kenya. Multiple outbreaks have been reported across the African continent and in Saudi Arabia and Yemen.


Most human cases are mild but in a small proportion of patients severe forms of the disease can develop, which can include ocular disease, encephalitis, or haemorhagic fever, which can be lethal.



WHO has highlighted Chikungunya as a major public health risk and has stated that further research and development is needed to mitigate the risk it poses.


Chikungunya is a mosquito-borne viral disease first described during an outbreak in southern Tanzania in 1952. It is spread from human to human by the bites of infected female mosquitoes—mostly Aedes aegypti and Aedes albopictus.


It causes fever, severe joint pain, muscle pain, headache, nausea, fatigue and rash. Joint pain is often debilitating and can vary in duration.


The disease shares some clinical signs with Dengue and Zika viruses and can be misdiagnosed in areas where they commonly occur.


No commercial vaccine against chikungunya is available.

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