A single-dose oral cholera vaccine intended for international travelers has been approved by the US Food and Drug Administration (FDA), making a cholera vaccine available to US travelers for the first time.
The vaccine, Vaxchora, made by PaxVax, is intended for people ages 18 through 64 who plan to travel to cholera-ridden areas, the FDA announced Jun 10. It targets Vibrio cholerae serogroup O1, the globally dominant cause of cholera.
Vaxchora is the only cholera vaccine approved by the FDA, the agency said. Two other oral cholera vaccines, Dukoral and ShanChol, are available elsewhere, but they require two doses and can take weeks to confer protection, according to the Centers for Disease Control and Prevention (CDC).
Until now, US travelers to cholera-affected areas have relied on preventive strategies like safe food and water practices and frequent hand washing, the FDA noted.
Vaxchora uses a live, weakened strain of V cholerae and is taken in a liquid dose of about 3 fluid ounces at least 10 days before travel to a cholera-affected area, the FDA said.
Up to 90% efficacy
The vaccine's efficacy was demonstrated in a randomized, placebo-controlled human challenge study of 197 US volunteers 18 to 45 years of age, the agency reported. Of the 197 volunteers, 68 Vaxchora recipients and 66 placebo recipients were challenged by oral ingestion of V cholerae. Vaccine efficacy was 90% among those challenged 10 days after vaccination and 80% in those challenged 3 months after vaccination.
In immunogenicity trials in the United States and Australia, at least 90% of adults who received the vaccine developed antibodies indicating protection against cholera, the FDA said.
"FDA approval of a new vaccine for a disease for which there has been no vaccine available is an extremely rare event," Nima Farzan, MBA, chief executive officer and president of PaxVax, said in a company press release. "We are proud to provide the only vaccine against cholera available in the US."
Vaxchora's effectiveness has not been established in people living in cholera-affected areas or in those who have pre-existing immunity because of previous exposure to V cholerae or receipt of a cholera vaccine, the company said. Also, the vaccine has not been shown to protect against disease caused by non-O1 serogroups.
PaxVax is based in Redwood city, Calif., and the vaccine is made in Hamilton, Bermuda.
Jun 10 FDA announcement
Jun 10 PaxVax press release