Safety and immunogenicity of ChAdOx1 MERS vaccine candidate in healthy Middle Eastern adults (MERS002): an open-label, non-randomised, dose-escalation, phase 1b trial
Mohammad Bosaeed, Hanan H Balkhy, Sultan Almaziad, Haya A Aljami, Hind Alhatmi, Hala Alanazi, Mashael Alahmadi, Ayah Jawhary, Mohammed W Alenazi, Abdulrahman Almasoud, Rawan Alanazi, Mustapha Bittaye, Jeremy Aboagye, Nahla Albaalharith, Sarah Batawi, Pedro Folegatti, Fernando Ramos Lopez, Katie Ewer, Khalid Almoaikel, Majed Aljeraisy, Adel Alothman, Sarah C Gilbert, Naif Khalaf Alharbi
Abstract
BACKGROUND: ChAdOx1-vectored vaccine candidates against several pathogens have been developed and tested in clinical trials and ChAdOx1 nCoV-19 has now been licensed for emergency use for COVID-19. We assessed the safety and immunogenicity of the ChAdOx1 MERS vaccine in a phase 1b trial in healthy Middle Eastern adults. METHOD: viral particles in a high-dose group. The primary objective was to assess the safety and tolerability of ChAdOx1 MERS, measured by the occurrence of solicited and unsolicited adverse events after vaccination for up to 28 days and occurrence of serious adverse events up to 6 months. The study is registered with ClinicalTrials.gov, NCT04170829. FINDINGS: Between Dec 17, 2019, and June 1, 2020, 24 participants were enrolled (six to the low-dose, nine to the intermediate-dose, and nine to the high-dose group) and received a dose; 23 were available for follow-up at 6 months. The one dose of ChAdOx1 MERS vaccine was well tolerated with no serious adverse event reported during the 6 months of follow-up. Most adverse events were mild (67, 74%) and moderate (17, 19%). Six (7%) severe adverse events were reported by two participants in the intermediate-dose group (two feverish, two headache, one joint pain, and one muscle pain). Pain at the injection site was the most common local and overall adverse event, reported by 15 (63%) of the 24 participants. The most common systemic adverse event was headache, reported by 14 (58%), followed by muscle pain reported by 13 (54%). The vaccine induced both antibody and T cell immune responses in all volunteers; antibodies peaked at day 28 and T cell responses peaked at day 14; and continued until the end of follow-up at 6 months. INTERPRETATION: The acceptable safety and immunogenicity data from this phase 1b trial of ChAdOx1 MERS vaccine candidate in Healthy Middle Eastern adults, combined with previous safety and immunogenicity data from a trial in the UK, support selecting the ChAdOx1 MERS vaccine for advancement into phase 2 clinical evaluation. FUNDING: UK Department of Health and Social Care, using UK Aid funding, managed by the UK National Institute for Health Research; and King Abdullah International Medical Research Center.