High-Dose Vaccine Could Reduce Cholera Outbreaks
A stronger single-dose live oral cholera vaccine (CVD 103-HgR) could more effectively protect individuals during outbreaks of cholera, according to the findings of a recent study.1
For their study, researchers at the University of Maryland School of Medicine conducted a randomized controlled trial in Mali, recruiting 150 participants between 18 and 45 years of age. Participants were randomly assigned to 1 oral dose of the attenuated Vibrio cholerae O1 classical Inaba vaccine CVD 103-HgR or 2 oral doses of the standard CVD 103-HgR inactivated cholera vaccine administered 2 weeks apart. Those assigned to the single-dose vaccine received a placebo as their second dose at week 2. The main outcome included seroconversion between baseline and day 14 after receiving the first and second vaccine doses.
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Fourteen days post-vaccination, the rate of seroconversion among participants who received the standard-dose CVD 103 HgR was 71.7% compared with 83.3% among those who received the high-dose vaccine. In addition, the rate of seroconversion after 1 dose of the standard vaccine was significantly lower than the high-dose vaccine.
The vibriocidal geometic mean titer (BMT) for the high-dose CVD 103- HgR vaccine exceed the standard-dose GMT at day 14 and was approximately 2-fold higher than the GMT of the standard-dose vaccine on day 7 and 14.
"Immunization with a single-dose cholera vaccine that could rapidly protect people in low-income countries who have not previously been exposed to cholera would be a significant asset in helping control outbreaks and lower mortality rates," the researchers concluded. "Given the highly encouraging results, we envision that as a matter of priority high-dose CVD 103-HgR will now be evaluated more completely in low income countries menaced by cholera."2
—Melissa Weiss
Reference:
1) Sow SO, Tapia MD, Chen WH, et al. Randomized, placebo-controlled, double-blind phase 2 trial comparing the reactogenicity and immunogenicity of a single standard dose to those of a high dose of CVD 103-HgR live attenuated oral cholera vaccine, with Shanchol inactivated oral vaccine as an open-label immunologic comparator. Clin Vaccine Immunol. 2017;24(12): e00265-17. https://doi.org/10.1128/CVI.00265-17.
2) High-dose cholera vaccine developed by UMSOM scientists shows promise for controlling outbreaks [press release]. Baltimore, MA: University of Maryland. http://www.medschool.umaryland.edu/news/2017/High-Dose-Cholera-Vaccine-Developed-by-UMSOM-Scientists-Shows-Promise-for-Controlling-Outbreaks.html. Accessed December 12, 2017.