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Clinical Trial
. 2019 Apr 19;219(10):1634-1641.
doi: 10.1093/infdis/jiy698.

PREVAIL I Cluster Vaccination Study With rVSVΔG-ZEBOV-GP as Part of a Public Health Response in Liberia

Fatorma K Bolay  1 , Greg Grandits  2 , H Clifford Lane  3 , Stephen B Kennedy  4 , Melvin P Johnson  5 , Mosoka P Fallah  1 , Barthalomew Wilson  5 , Wissedi S Njoh  6 , Laura A McNay  3 , Lisa E Hensley  3 , Elizabeth S Higgs  3
Affiliations
Clinical Trial

PREVAIL I Cluster Vaccination Study With rVSVΔG-ZEBOV-GP as Part of a Public Health Response in Liberia

Fatorma K Bolay et al. J Infect Dis. .

Abstract

Objective: In November 2015, a 15-year-old boy received a diagnosis of Ebola virus disease (EVD) at the John F. Kennedy Medical Center in Monrovia, Liberia. Two additional family members received a diagnosis of EVD. The protocol for a phase 2 placebo-controlled trial of 2 Ebola vaccines was amended and approved; in 4 days, a single-arm cluster vaccination trial using the Merck rVSVΔG-ZEBOV-GP vaccine was initiated. Here, we evaluate the safety and immunogenicity of the vaccine and discuss challenges for its implementation in a small Ebola outbreak.

Method: We conducted a ring vaccination study among contacts and contacts of close contacts of EVD cases a in Monrovia. Participants were evaluated 1 and 6 months after vaccination.

Results: Among 650 close contacts and contacts of close contacts of EVD cases, 210 (32%) consented and were vaccinated with rVSVΔG-ZEBOV-GP. Of those vaccinated, 189 (90%) attended the month 1 follow-up visit; 166 (79%) attended the month 6 visit. No serious adverse events were reported. Among 88 participants without an elevated antibody level at baseline, 77.3% (95% confidence interval, 68.5-86.1) had an antibody response at 1 month.

Conclusions: The Merck rVSVΔG-ZEBOV-GP vaccine appeared to be safe and immunogenic among the vaccinated individuals. However, fewer than one third of eligible individuals consented to vaccination. These data may help guide implementation decisions for of cluster vaccination programs in an Ebola cluster outbreak response situation.

Keywords: Ebola virus; Ebola virus disease; Liberia; PREVAIL; cluster vaccination; outbreak response; rVSVΔG-ZEBOV-GP vaccine; ring vaccination; vaccine.

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Figures

Figure 1.
Figure 1.
Initial vaccination response time line. ETU, Ebola treatment unit; FAQ, frequently asked question; IRB, institutional review board; JFK Hospital, John F. Kennedy Medical Center; MoH, Minister of Health; SMC, Social Mobilization, Community Engagement, and Communications.
Figure 2.
Figure 2.
Flow diagram for cluster vaccination study in Liberia. ETU, Ebola treatment unit; EVD, Ebola virus disease; HCW, healthcare worker; JFK Hospital, John Fitzgerald Kennedy Memorial Hospital; MoH, Ministry of Health.
Figure 3.
Figure 3.
Distribution of days from case diagnosis to participant vaccination.
Figure 4.
Figure 4.
Distribution of antibody levels before and 1 month after vaccination. Median antibody levels before vaccination were 151 EU/mL (interquartile range, 99–241 EU/mL). One month after vaccination, these antibody levels were 1339 EU/mL (interquartile range, 1103–1626 EU/mL).
See this image and copyright information in PMC

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