# Long-Term Clinical Safety of the Ad26.ZEBOV and MVA-BN-Filo Ebola Vaccines: A Prospective, Multi-Country, Observational Study

## TL;DR

This study confirms the long-term safety of two Ebola vaccines, Ad26.ZEBOV and MVA-BN-Filo, over a 5-year period in multiple countries.

## Contribution

The study provides the first long-term safety data for Ad26.ZEBOV and MVA-BN-Filo vaccines across multiple countries and diverse populations.

## Key findings

- Only 8% of participants experienced at least one serious adverse event, with no deaths or life-threatening events.
- The incidence rate of serious adverse events was 27.4 per 1000 person-years, with most being unrelated to the vaccines.
- No major safety issues were identified, and only one serious adverse event was considered related to the vaccines.

## Abstract

In this prospective, observational study (ClinicalTrials.gov Identifier: NCT02661464), long-term safety information was collected from participants previously exposed to the Ebola vaccines Ad26.ZEBOV and/or MVA-BN-Filo while enrolled in phase 1, 2, or 3 clinical studies. The study was conducted at 15 sites in seven countries (Burkina Faso, France, Kenya, Tanzania, Uganda, the United Kingdom, and the United States). Adult participants and offspring from vaccinated female participants who became pregnant (estimated conception ≤28 days after vaccination with MVA-BN-Filo or ≤3 months after vaccination with Ad26.ZEBOV) were enrolled. Adults were followed for 60 months after their first vaccination, and children born to female participants were followed for 60 months after birth. In the full analysis set (n = 614 adults; median age [range]: 32.0 [18–65] years), 49 (8.0%) had ≥1 serious adverse event (SAE); the incidence rate of any SAE was 27.4 per 1000 person-years (95% confidence interval: 21.0, 35.2). The unrelated SAEs of malaria were reported in the two infants in the full analysis set, aged 11 and 18 months; both episodes were resolved. No deaths or life-threatening SAEs occurred during the study. Overall, no major safety issues were identified; one related SAE was reported. These findings support the long-term clinical safety of the Ad26.ZEBOV and MVA-BN-Filo vaccines.