MERS Vaccines

Authored by
Staff
Last reviewed
October 2, 2024
Content Overview
MERS vaccine candidates protect people from severe infections related to interactions with camels and llamas.

Middle East Respiratory Syndrome (MERS) Vaccine Candidates, Clinical Trials, Side Effects

The U.S. Food and Drug Administration (FDA), the European Medicines Agency (EMA), the World Health Organization (WHO), and the Kingdom of Saudi Arabia have not approved a Middle East Respiratory Syndrome Coronavirus (MERS-CoV) vaccine candidate as of October 2024. The WHO says several vaccine candidates are conducting human clinical trials in 2024. Efforts to develop an effective and safe human MERS-CoV vaccine have progressed, with a few vaccine candidates having reached human studies; these vaccines are based on DNA platforms, viral vector platforms, and modified vaccinia Ankara. On April 10, 2023, the U.S. government announced Project-NextGen, which intends to empower companies to expedite the development of vaccines and therapies for human coronaviruses such as MERS.

MERS-COV Vaccine Candidates

Oxford University's Pandemic Sciences Institute and Barinthus Biotherapeutics Inc. are developers of the ChAdOx1 MERS vaccine and announced on September 15, 2023, that eighty-four people aged 50 to 70 will participate in a phase 1 study in Liverpool. This study follows two previous Phase I clinical trials in the U.K. and Saudi Arabia. VTP-500 (ChAdOx1) MERS-CoV is a vaccine candidate from the University of Oxford that consists of the replication-deficient simian adenovirus vector ChAdOx1 MERS Spike protein antigen. The VTP-500 vaccine is administered as a single administration and with a homologous prime booster. CEPI is funding up to $34.8 million to develop and stockpile VTP-500 vaccines. Due to VTP-500's potential to significantly address the unmet need for MERS, the EMA has confirmed support for the program through the PRIME designation. 

MVA MERS-S (Modified Vaccinia virus Ankara) is a vaccine candidate that contains the full-length spike gene of MERS-CoV. Vaccination with MVA-MERS-S had a favorable safety profile without severe adverse events. Homologous prime-boost immunization induced humoral and cell-mediated responses against MERS-CoV. In June 2023, the U.S. CDC reported after a single modified vaccinia virus Ankara-MERS-S vaccine and seropositive camels showed increased levels of MERS-CoV‒specific T cells and antibodies, indicating the suitability of camel vaccinations in disease-endemic areas as a promising approach to control infection.

BVRS-GamVac-Combi is conducting phase 1/2 clinical studies sponsored by the Gamaleya Research Institute of Epidemiology and Microbiology, which is part of the Health Ministry of the Russian Federation.

The inactivated rabies vectored SARS-CoV-2 S1 vaccine CORAVAX is adjuvanted with MPLA-AddaVax, a TRL4 agonist, induced high levels of neutralizing antibodies and generated a strong Th1-biased immune response. 

Avacc 101 vaccine candidate is designed to provide broad protection against SARS-CoV-1, SAR-CoV-2, and MERS-CoV. 

Novavax's MERS investigational vaccine was paused at the pre-clinical process.

Ralph Baric's lab at the University of North Carolina at Chapel Hill, the office of the U.S. NIAID, negotiated an agreement to develop a MERS mRNA vaccine candidate.

MERS Outbreaks

The U.S. Centers for Disease Control and Prevention (CDC) says Middle East respiratory syndrome coronavirus (MERS-CoV) is a viral respiratory infection. The zoonotic source of this virus remains unknown. A study published in The Lancet in July 2024 highlighted the potential threat of MERS-CoV, subgenus Merbecovirus, to global health. MERS-CoV circulates in dromedary camels in the Arabian Peninsula and occasionally causes human spillover infections. The emergence of MERS-CoV in camels and humans was preceded by a critical recombination event in which the ancestral receptor binding domain was replaced with a different merbecovirus lineage, thereby altering receptor usage. A key concern is the ability of the virus to use diverse cell entry receptors, including ACE2. 

The U.S. CDC's Emerging Infectious Diseases published a study (Volume 30, Number 3) in March 2024 that identified more than three case clusters in camels from different areas of Nairobi, Kenya, and a 15% infection rate in slaughterhouse workers. In February 2024, the WHO reported that between August 2023 and February 2024, the Ministry of Health of the Kingdom of Saudi Arabia reported four MERS-CoV cases, including two deaths.

Since the first report of MERS-CoV infection in a patient with pneumonia who died in a Jeddah hospital in Saudi Arabia in 2012, about 2.625 cases of MERS, including 951 associated fatalities (36%), have been reported from 27 countries in six World Health Organization as of June 2024.