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 to the end of April 2019, the total global number of laboratory-confirmed MERS cases reported to WHO is 2428, with 838 associated deaths, (case–fatality rate: 34.5%) were reported globally. The majority of these cases were reported from Saudi Arabia (2037 cases, including 760 related deaths).

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

From January to March 2019, there were 61 reported MERS cases in the city of Wadi Aldwasir, Saudi Arabia. Investigations into the source of infection of the 61 cases found that 37 were health-care acquired infections, 14 were primary cases presumed to be infected from contact with dromedary camels and the remaining infections occurred among close contacts outside of health care settings.

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 35% of people reported as having MERS have died, many of whom already had an underlying medical condition.

The age group 50–59 years continues to be at highest risk for acquiring infection of primary cases. The age group 30–39 years is most at risk for secondary cases.

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.

CEPI has 5 MERS vaccine candidates in its portfolio.

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 in 2018. 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.

In June 2019, the Indian Government confirmed a new case of Nipah virus infection in a 23-year-old man in Kerala, India – the same state that experienced a deadly outbreak of the disease last year. The patient was hospitalised and was discharged after 2 months. In total, 355 case contacts were monitored and 7 were kept in the isolation ward of a government hospital.

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.

Through a 14-year study in Bangladesh, another country prone to Nipah outbreaks, research published in May 2019 identified that increasing age and respiratory problems were key indicators in the infectivity of the virus.

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.

CEPI has four Nipah vaccine candidates in its portfolio.

The experimental antiviral drug, Remdesivir, which is being tested against the Ebola virus in the ongoing outbreak in the DRC, has also shown promise in protecting non-human primates against infection with Nipah virus. In a new trial, published in Science Translational Medicine, four African Green Monkeys given intravenous remdesivir survived lethal doses of Nipah virus; the other four that did not, died within 8 days.

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.

CEPI has two Rift Valley fever vaccine candidates in its portfolio.