FDA Approves First Cholera Vaccine in the US

The US Food and Drug Administration (FDA) today approved the first vaccine available in the United States for the prevention of cholera (Vaxchora, PaxVax Bermuda Ltd) caused by serogroup 01, for use in adults aged 18 through 64 years traveling to cholera-affected regions.

The World Health Organizations reports that serogroup 01 is the primary cause of cholera worldwide.

The vaccine is the only one approved by the FDA for cholera prevention. It is a live, weakened vaccine administered as a single, oral liquid dose of about three fluid ounces at least 10 days before travel to a cholera-affected region. The only other existing cholera-prevention vaccines require two doses, according to the Centers for Disease Control and Prevention (CDC). A single-dose vaccine is especially beneficial to a person who needs to travel to a cholera-affected region on short notice.

Cholera is caused by the Vibrio cholera bacteria, and is acquired by consuming contaminated water or food. It causes watery diarrhea that can become quite severe. The infection is usually mild but can become potentially life-threatening, with profuse diarrhea and vomiting, and eventual dehydration. Prompt administration of antibiotics and fluid replacement are critical to the disease's treatment.

"The approval of Vaxchora represents a significant addition to the cholera-prevention measures currently recommended by the Centers for Disease Control and Prevention for travelers to cholera-affected regions," Peter Marks, MD, PhD, director of the FDA's Center for Biologics Evaluation and Research, said in an FDA news release.

Cholera is rare in the US, but those who travel to regions of the world with inadequate sanitation, water treatment, and sewage treatment are at risk for the infection. The CDC recommends that those who travel to cholera-affected regions follow safe food and water practices and frequent hand washing, among other prevention strategies.

The decision follows a discussion of data from several trials. One trial was a randomized, placebo-controlled, human challenge study of 197 US volunteers aged from 19 through 45 years. The researchers randomly assigned 68 participants to receive the vaccine and 66 participants to receive placebo. Study participants later underwent oral challenge of V cholerae, the cholera-causing bacterium.

Vaccine efficacy was 90% among participants challenged 10 days after vaccination and 80% among participants challenged 3 months after vaccination.

The study allowed participants who became ill to receive antibiotics and fluid replacement. The study also sought to prevent transmission of the illness into the community by providing for antibiotic administration to asymptomatic participants.

The company also conducted two placebo-controlled trials to evaluate vaccine response in adults aged 18 through 64 years in the US and Australia. In participants aged 18 through 45 years, 93% of vaccinated participants produced antibodies indicative of protection against the illness. In those aged 46 through 64 years, 90% produced antibodies indicative of protection against the disease. Researchers have not tested the vaccine's effectiveness in those living in cholera-affected regions, according to the FDA.

The company also conducted four randomized, placebo-controlled, multicenter clinical trials to evaluate the vaccine's safety. The researchers randomly assigned 3235 participants to receive Vaxchora and 562 participants to receive placebo. The most frequently reported adverse reactions were fatigue, headache, abdominal pain, nausea and vomiting, anorexia, and diarrhea.

The FDA granted fast track designation and priority review status to the Vaxchora application — programs "intended to facilitate and expedite the development and review of medical products that address a serious or life-threatening condition," according to the FDA news release.

The FDA also awarded the company a tropical disease priority review voucher, a provision of the Food and Drug Administration Amendments Act of 2007 intended to encourage the development of new drugs and biologicals to prevent and treat certain tropical diseases.

Additional information is available at FDA: Vaccines, Review Designations