Privately held PaxVax is getting a boost for its cholera vaccine with the U.S. Centers for Disease Control and Prevention now recommending Vaxchora for adults aged 18 to 64 traveling to areas where cholera is active. Vaxchora is the only FDA-approved cholera vaccine.
The agency’s Advisory Committee on Immunization Practice made the recommendation last June, just two weeks after the FDA approved Vaxchora, a single-dose, live attenuated oral cholera vaccine. The CDC adopted the recommendation as published in the recent issue of Morbidity and Mortality Weekly Report.
PaxVax's vaccine demonstrated a 90% protection rate at 10 days after vaccination and about 80% at three months in a cholera challenge trial. The vaccine’s efficacy after that time is yet unknown.
“The primary prevention strategy for cholera is consistent access to and exclusive use of safe water and food and frequent handwashing,” CDC officials state in the report. However, when traveling to places where those resources are limited and where the bacteria is so prevalent that human beings can encounter it unexpectedly, protection from a vaccine is the best option, according to the agency.
Although cholera is rare in the U.S., cases have been increasing in other parts of the world in recent years. The CDC estimated the disease is endemic in about 60 countries worldwide, mainly in Africa, Southeast Asia and the Caribbean, causing about 2.9 million cases and 95,000 deaths annually.
The U.S. reported 42 cholera cases in 2011 after an outbreak started in Haiti in 2010, but has seen fewer than 25 cases each year since then. The CDC notes that most U.S. travelers do not visit areas with active cholera transmission and are rarely at risk, but 80% of U.S. cases are associated with travel to endemic regions.
Two other oral cholera vaccines are available outside the U.S.: Valneva’s Dukoral and Shanchol by Sanofi’s Shantha, both two-dose regimens.
The CDC recommends that travelers do not receive antibiotics in the 14 days before receiving the vaccine.
Redwood City, California-based PaxVax also recently started the first clinical trial in more than 30 years of a vaccine against adenovirus serotypes 4 and 7—which can cause acute respiratory distress—in collaboration with the U.S. Army Medical Materiel Development Activity and the Walter Reed Army Institute of Research.