Ebola Vaccine Immune Responses Persist After One Year

All active vaccine recipients maintained Ebola virus-specific immunoglobulin responses at day 360.
All active vaccine recipients maintained Ebola virus-specific immunoglobulin responses at day 360.

HealthDay News -- According to a research letter published in JAMA, heterologous primary and booster vaccination schedule of the adenovirus type 26 vector vaccine encoding Ebola virus glycoprotein (Ad26.ZEBOV) and the modified vaccinia virus Ankara vector vaccine, which encode glycoproteins from Ebola, Sudan, Marburg, and Tai Forest viruses nucleoprotein (MVA-BN-Filo) immunity, persisted after one year.

Rebecca Winslow, from the University of Oxford in the United Kingdom, and colleagues reported follow-up data at one year for the Ad26.ZEBOV and MVA-BN-Filo vaccines.

Eighty-seven healthy participants aged 18 to 50 years were enrolled; 72 were randomized to four groups and received Ad26.ZEBOV or MVA-BN-Filo followed by boosting with the alternate vaccine 28 or 56 days later. 

An additional group of 15 participants were vaccinated with Ad26.ZEBOV followed by MVA-BN-Filo 14 days later. Sixty-four participants attended follow-up at day 360.

The researchers found that there were no reports of serious adverse events from day 240 to 360. At day 360 all of the active vaccine recipients maintained Ebola virus-specific immunoglobulin G responses. 

In 60 to 83% of participants receiving Ad26.ZEBOV first followed by MVA-BN-Filo as a booster, vaccine-induced T-cell responses persisted, compared with 69 to 100% among those receiving MVA-BN-Filo followed by Ad26.ZEBOV.

"Additional research is also warranted to explore the persistence of immunity beyond one year following immunization and response to booster doses of vaccine," the authors write.

One author disclosed financial ties to the pharmaceutical industry. One author reported pending patents related to work in the study.

Reference

Winslow RL, et al. "Immune Responses to Novel Adenovirus Type 26 and Modified Vaccinia Virus Ankara–Vectored Ebola Vaccines at 1 Year." JAMA. 2017;317(10): 1075-1077 doi:10.1001/jama.2016.20644 [Epub ahead of print]

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