Avian Flu Diary: WHO: Steep Rise In Global Cholera Outbreaks Creates Vaccine Shortages

OCV Clinic in Haiti in 2013 - Credit CDC PHIL

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The unwelcome news two weeks ago that Cholera has broken out again in Haiti after nearly 3 years (see
WHO: Risk Assessment) is only the latest example of this scourge's resurgence in 2022. Other nations, (including Malawi and Syria) are facing large outbreaks, and smaller outbreaks have been reported in more than 2 dozen other countries.

While rarely a problem in developed countries with modern water treatment and good sanitation, Cholera remains a serious threat in dozens of nations where these facilities have been degraded by natural disasters, war, or civil strife.

This from the World Health Organization Fact Sheet.

Cholera
30 March 2022

Key facts

Most of those infected will have no or mild symptoms and can be successfully treated with oral rehydration solution.
A global strategy on cholera control, Ending Cholera: a global roadmap to 2030, with a target to reduce cholera deaths by 90% was launched in 2017.
Researchers have estimated that each year there are 1.3 to 4.0 million cases of cholera, and 21 000 to 143 000 deaths worldwide due to cholera (1)
Cholera is an acute diarrhoeal disease that can kill within hours if left untreated.
Provision of safe water and sanitation is critical to prevent and control the transmission of cholera and other waterborne diseases.
Severe cases will need rapid treatment with intravenous fluids and antibiotics.
Oral cholera vaccines should be used in conjunction with improvements in water and sanitation to control cholera outbreaks and for prevention in areas known to be high risk for cholera.
Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. Cholera remains a global threat to public health and an indicator of inequity and lack of social development.

The last Cholera pandemic (the 7th) supposedly ended in 1975, but many would argue it continues today, with flare ups every few years.

Starting in 1991, and running through 1994, a Cholera epidemic swept out of Peru infecting more than 1 million South Americans, and claiming nearly 10,000 lives.

In 1992, a new serogroup – Designated V. cholerae 0139 Bengal – emerged in Bangladesh and caused an extensive epidemic.

And following their 2010 devastating 7.0 Earthquake, Cholera re-emerged in Haiti (likely imported by a relief worker from Asia) after an absence of 100 years, sparking a nearly decade-long outbreak.

There are currently 3 approved oral Cholera Vaccines (OVC) - Dukoral®, Shanchol™, and Euvichol-Plus® - but all three require two doses for full (3 year) protection. The demands for the vaccine in 2022 have risen markedly, and now - as the WHO explains below - there is now a shortage necessitating the administration of a single dose instead of two.

Shortage of cholera vaccines leads to temporary suspension of two-dose strategy, as cases rise worldwide

The exceptional decision reflects the grave state of the cholera vaccine stockpile

19 October 2022 News release New York / Geneva Reading time: 2 min (546 words)

A strained global supply of cholera vaccines has obliged the International Coordinating Group (ICG) — the body which manages emergency supplies of vaccines — to temporarily suspend the standard two-dose vaccination regimen in cholera outbreak response campaigns, using instead a single-dose approach.

The pivot in strategy will allow for the doses to be used in more countries, at a time of unprecedented rise in cholera outbreaks worldwide.

Since January this year, 29 countries have reported cholera cases, including Haiti, Malawi and Syria which are facing large outbreaks. In comparison, in the previous 5 years, fewer than 20 countries on average reported outbreaks. The global trend is moving towards more numerous, more widespread and more severe outbreaks, due to floods, droughts, conflict, population movements and other factors that limit access to clean water and raise the risk of cholera outbreaks.

The one-dose strategy has proven to be effective to respond to outbreaks, even though evidence on the exact duration of protection is limited, and protection appears to be much lower in children. With a two-dose regimen, when the second dose is administrated within 6 months of the first, immunity against infection lasts for 3 years.

The benefit of supplying one dose still outweighs no doses: although the temporary interruption of the two-dose strategy will lead to a reduction and shortening of immunity, this decision will allow more people to be vaccinated and provide them protection in the near term, should the global cholera situation continue deteriorating.

The current supply of cholera vaccines is extremely limited. Its use for emergency response is coordinated by the ICG which manages the global stockpile of oral cholera vaccines. Of the total 36 million doses forecast to be produced in 2022, 24 million have already been shipped for preventive (17%) and reactive (83%) campaigns and an additional 8 million doses were approved by the ICG for the second round for emergency vaccination in 4 countries, illustrating the dire shortage of the vaccine. As vaccine manufactures are producing at their maximum current capacity, there is no short-term solution to increase production. The temporary suspension of the two-dose strategy will allow the remaining doses to be redirected for any needs for the rest of the year.

This is a short-term solution but to ease the problem in the longer term, urgent action is needed to increase global vaccine production.

The ICG will continue to monitor the global epidemiological trends as well as the status of the cholera vaccine stockpile, and will review this decision regularly.