norovirus

Norovirus Vaccine Formulations Well Tolerated

New formulations of the norovirus vaccine (NoV) were well tolerated among healthy adults, according to the findings of a recent study. The best response was from 15μg GI.1/50μg GII.4c vaccine, which had the best balance of immunogenicity.

The study included 420 healthy adult participants from 18 to 64 years of age who were randomly assigned to 4 equal groups. On days 1 and 28, participants received either intramuscular control vaccine for hepatitis A, or 1 of 11 NoV formulations that contained varying dosages of GI.1 and GII.4c genotype bivalent virus-like particle (VLP) antigens with al(OH)3, and 0μg, 15μg or 50μg MPL. The immunogenicity of the different formulations was assessed on days 1, 28, 56, 208 and 393. Systemic and local reactions to the vaccines were recorded for 7 days, adverse events were documented for 56 days, and serious adverse events were reported throughout the trial.
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Overall, the researchers found that all NoV formulations induced similar increases in Pan-Ig, IgA, and histo-blood group binding antigen-blocking antibodies by day 56. These increases mostly occurred after 1 dose and persisted from baseline to day 393.

In addition, higher GI.1 content was found to interfere with GII.4c responses and responses did not benefit from MPL.

Mild injection site pain, headache and fatigue were common reactions to the vaccine, and no vaccine-related serious adverse events were observed. 

“All candidate NoV formulations were well tolerated,” the researchers concluded. “Overall, 15μg GI.1/50μg GII.4c elicited the best balance of immunogenicity with no clear benefit of MPL, and is the candidate formulation being taken forward in clinical development.”

—Melissa Weiss

Reference:

Leroux-Roels G, Cramer JP, Mendelman PM, et al. Safety and immunogenicity of different formulations of norovirus vaccine candidate in healthy adults: a randomized, controlled, double-blind clinical trial [published online November 13, 2017]. J Infect Dis. https://doi.org/10.1093/infdis/jix572.