MERS Vaccines 2023

Middle East Respiratory Syndrome (MERS) Vaccines 2023

The U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have not approved a Middle East Respiratory Syndrome Coronavirus (MERS-CoV) vaccine candidate as of August 2023. Still, several vaccine candidates are conducting clinical trials. 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 (GLS-5300) and viral vector platforms (ChAdOx1) and modified vaccinia Ankara [MVA). 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 coronaviruses such as MERS. A study published by the  International Journal of Infectious Diseases on March 29, 2023, confirms MERS-CoV remains a threat to global health security. as variants continue circulating in humans and camels. In addition, recent recombination rates indicate co-infections with different MERS-CoV Clades: clade B (n=462), A (n=10), and C (n=5).

MERS-COV Vaccine Candidates 2023

Oxford University's Pandemic Sciences Institute and developer of the ChAdOx1 MERS vaccine announced on September 15, 2023, eighty-four people aged 50 to 70 will participate in a study in Liverpool, which follows two previous Phase I clinical trials in the U.K. and Saudi Arabia. 

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 vaccination, 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, Health Ministry of the Russian Federation.

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.

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.

MERS Cases 2023

The U.S. Centers for Disease Control and Prevention (CDC) says MERS is a viral respiratory infection. The zoonotic source of this virus remains unknown; however, 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 2,605 cases with 945 associated fatalities (36%) have been reported from 27 countries in six World Health Organization.

MERS and SARS-CoV-2

A study published by the journal Nature in March 2023 stated it is generally believed that sarbecoviruses, such as SARS-CoV-2 and SARS-CoV, use angiotensin-converting enzyme 2 (ACE2) as the entry receptor, while merbecoviruses, such as MERS-CoV, HKU4, and HKU25, utilize dipeptidyl peptidase 4 (DPP4) as the entry receptor. Previous findings (2022) reveal a potential zoonotic threat that MERS-CoV could, during its evolution, be gaining the ability to use hACE2 as an entry receptor and, thus, could also coinfect ACE2-expressing cells with SARS-CoV-2.

MERS-CoV News 2023

September 15, 2023 - Oxford and Liverpool scientists launch a new MERS vaccine phase 1 clinical trial.

May 2023 - The Lancet published Vaccination strategies for mitigating MERS-CoV outbreaks. Affected countries should have plans for maintaining MERS-CoV vaccine stockpiles that are sufficiently available and ready to use, especially in populations at high risk of infection during outbreaks.

March 3, 2023 - Abstract: MERS-CoV clade B viruses are found in camelids and humans in the Middle East, but clade C viruses are not. The kinetics by which llamas shed infectious MERS-CoV are similar to those of dromedary camels. We provide experimental evidence for the extended shedding of MERS-CoV clade B viruses in llamas, which might explain why they outcompete clade C strains in the Arabian Peninsula.

December 7, 2022 - The journal Nature published an article: Close relatives of MERS-CoV in bats use ACE2 as their functional receptors, that describes MERS-CoV-related viruses that use ACE2 as an entry receptor, underscoring a promiscuity of receptor use and a potential zoonotic threat.

January 31, 2022 - The peer-reviewed Frontiers in Immunology published an ORIGINAL RESEARCH article: Inactivated Rabies Virus Vectored MERS-Coronavirus Vaccine Induces Protective Immunity in Mice, Camels, and Alpacas. The current results demonstrate that the inactivated rabies virus-vectored MERS-CoV vaccine is safe, efficacious, and can induce robust protective immune responses, representing a promising MERS camelid vaccine candidate and warranting further efficacy study.

January 28, 2022 - The Journal of Microbiology published: the MERS coronavirus vaccine development: Updating Clinical Studies using platform technologies.

November 4, 2021 - Vaccitech plc announced the publication in The Lancet Microbe of the first Phase 1 clinical trial conducted in the Middle East evaluating the safety and tolerability of the ChAdOx1 MERS (Middle Eastern Respiratory Syndrome) vaccine candidate.

November 3, 2021 - The Lancet published: Safety and immunogenicity of ChAdOx1 MERS vaccine candidate in healthy Middle Eastern adults (MERS002): an open-label, non-randomized, dose-escalation, phase 1b trial. Results Interpretation: The acceptable safety and immunogenicity data from this phase 1b trial of the ChAdOx1 MERS vaccine candidate in Healthy Middle Eastern adults, combined with previous safety and immunogenicity data from a trial in the U.K., support selecting the ChAdOx1 MERS vaccine for advancement into phase 2 clinical evaluation.

August 4, 2021 - INOVIO announced that the company had dosed the first subject in its Phase 2 trial to evaluate INO-4700, its DNA vaccine candidate for preventing MERS.

April 14, 2021 - A team of researchers in the Kingdom of Saudi Arabia studied the antibody responses in 48 human MERS-CoV infection survivors with variable disease severity in Saudi Arabia. MERS-CoV–specific neutralizing antibodies were detected for six years after postinfection. Choe et al. showed that patients with severe disease had robust MERS-CoV neutralizing antibody titers for one year. Conversely, patients with mild disease had waning antibody responses over time. 

July 24, 2019 - The Lancet published: Safety and immunogenicity of an anti-Middle East respiratory syndrome coronavirus DNA vaccine: a phase 1, open-label, single-arm, dose-escalation trial. Interpretation - The GLS-5300 MERS coronavirus vaccine was well tolerated with no vaccine-associated serious adverse events. Immune responses were dose-independent, detected in more than 85% of participants after two vaccinations, and durable through 1 year of follow-up. The data support further development of the GLS-5300 vaccine, including additional studies to test the efficacy of GLS-5300 in a region endemic to MERS coronavirus.