A global shortage of oral cholera vaccine coupled with more widespread and severe cholera outbreaks in recent months have forced restrictions on the administration of the vaccine. The International Coordinating Group (ICG), which manages and coordinates the provision of emergency vaccine supplies, announced in October 2022 that a single-dose regimen will temporarily replace the standard two doses.
The World Health Organization (WHO) noted that since January 2022, there have been cholera outbreaks in 29 countries, up from an average of 20 affected countries in recent years. The number of outbreaks around the world has risen as a result of natural and human-made disasters. Floods, droughts, and violent conflicts have displaced millions of people, who as a result may have limited access to clean water and live in settings with poor sewage management, increasing the risk of cholera.
The usual two-dose regimen of cholera vaccine provides immunity that lasts about three years. A single dose offers short-term immunity-possibly as short as six months-but the WHO states that the single-dose regimen has proven effective in controlling outbreak situations. Widespread short-term immunity during an outbreak can sometimes buy time for potable water and sanitation systems to be put into place.
A shortage of vaccine manufacturers has exacerbated the crisis. A subsidiary of Sanofi pharmaceuticals in the past contributed about 15% of the ICG's emergency cholera vaccine stockpile, but the company stopped production last year and plans to exit the market at the end of 2023. The remaining manufacturers of the vaccine are working at capacity, and increased production is unlikely before 2024. The ICG is looking for new manufacturers, but there is little commercial incentive to produce this inexpensive ($1 to $3 per dose) vaccine because cholera is less common in middle- and high-income countries.
Economic development, universal access to safe drinking water, and adequate sanitation could prevent cholera outbreaks and allow better control of cholera in endemic areas. As Philippe Barboza, the cholera team leader at the WHO, told the Lancet, "It's unacceptable that, in the 21st century, people are still dying from an easily preventable and treatable disease."-Betsy Todd, MPH, RN