Cholera vaccines: When to inject, Kinds of vaccines, How wide they are used?
How do people get cholera?
Cholera is a bacterial infection of the intestines. The good news is, cholera is easy to treat if it's caught early by injecting Cholera vaccine. People who have mild to moderate cases usually get better within a week. Even people with severe cases of cholera recover fully in a week or so if they get medical care.
People get cholera from eating or drinking food or water that's been contaminated with the feces (poop) of someone who has cholera. This is one reason why cholera is rare in countries with good sanitation systems. Things like flush toilets, sewer systems, and water treatment facilities keep poop out of the water and food supply.
But for people living in places without good sanitation, cholera is more of a risk. Cholera epidemics can also sometimes happen after a disaster (like an earthquake or flood) if people are living in tent cities or other places without running water or proper sanitation systems.
When should we inject the Cholera vaccine?
It is important to distinguish between endemic and epidemic cholera. For the control of epidemic cholera, selective vaccination of populations at a definably high risk of an epidemic, or reactive vaccination shortly after the onset of the epidemic, can be considered. Because populations experiencing epidemic cholera often have limited background natural immunity to cholera, vaccines must be effective in immunologically naive persons, and they should target all age groups, as the risk of epidemic cholera tends to be age independent.
For endemic cholera, vaccines should be able to immunize in the face of the background natural immunity to cholera that develops in recurrently exposed populations. Vaccination may target preschool and school-age children rather than adults in view of the higher risk of cholera in younger age groups in endemic settings. Long-term protection is more critical than early onset of protection after initiation of dosing for vaccines against endemic cholera. In contrast, early onset of protection after the first dose of vaccine would be of greater importance for vaccines used reactively in epidemic situations, and duration of protection would be of lesser importance, according to sciencedirect.
Why are cholera vaccines not widely used?
|Photo: Health Europa|
According to WHO, vaccination has been shown to be a cost‒effective, more immediate option for cholera control and prevention. Two oral cholera vaccines have been available for years, but have not been widely used due to either cost or licensing restrictions. With the availability of lower-cost options, cholera vaccine is increasingly being considered for use in eendemic countries or during outbreaks. Current vaccines are two-dose inactivated vaccines. Several live oral cholera vaccines, including a single-dose vaccine that was recently approved by the United States Food and Drug Administration, are currently under consideration for future vaccination policy. A single-dose regimen would have great potential for use in emergency or epidemic situations.
In 2011 the first low-cost oral cholera vaccine obtained prequalification by WHO for international use. Prequalification certifies the acceptability of a vaccine for purchase by the United Nations Children’s Fund (UNICEF) and other United Nations (UN) agencies; the main vaccine procurers for low-income countries. In 2013, Gavi, the Vaccine Alliance approved financing of a stockpile of an oral cholera vaccine for use in endemic and epidemic settings. Although the financing (115 million United States dollars) could support a stockpile of 20 million doses over the following 5 years, full capacity could not be achieved due to a short supply of vaccine. Thus, vaccine deployment was low, despite demand for the vaccine. To help overcome anticipated supply constraints, the International Vaccine Institute facilitated the transfer of the vaccine technology to a second manufacturer, which led to WHO prequalification of a second affordable oral cholera vaccine for global use in December 2015. This has already begun contributing to the global stockpile of oral cholera vaccines12 and is projected to increase the supply significantly in 2017. The same manufacturing technology for the vaccine was transferred to a third manufacturer, who is expected to begin production of the first-ever oral cholera vaccine registered and licensed for use in Bangladesh ‒ one of the countries most affected by cholera ‒ in the near future.
As demonstrated by the creation of the stockpile, global interest in cholera control has increased, which should help pave the way to global use, availability and distribution of the vaccine, particularly in low-income countries through the UNICEF and Gavi procurement mechanisms. It is still not known, however, what the demand would be for oral cholera vaccines.
Based on experiences from other vaccines, even with increased production capacity, adoption of new vaccines into policy takes time, and actual demand may not meet projected demand. The long-term support for oral cholera vaccines depended on impact and cost information gathered through 2018. The Gavi board reconvened in 2018 to reconsider its oral cholera vaccine strategy for 2018–2022, which could have an impact on the future direction of oral cholera vaccination, including its financing. Moreover, an increased supply will not alleviate vaccine delivery costs, a barrier that many countries in need of oral cholera vaccines face. Understanding financing constraints on the increased use of oral cholera vaccines will be critical in the coming years but is a complex issue that is beyond the scope of our report.
Current vaccines for dealing with Cholera
|Photo: Contagion Live|
Vaxchora® (lyophilized CVD 103-HgR)
Please note: In December 2020, the maker of this cholera vaccine temporarily stopped making and selling it. This vaccine may be in limited supply or unavailable.
The FDA approved external icon a single-dose live oral cholera vaccine called Vaxchora® (lyophilized CVD 103-HgR) in the United States. The Advisory Committee on Immunization Practices (ACIP) voted to approve the vaccine for adults 18 – 64 years old who are traveling to an area of active cholera transmission.
An area of active cholera transmission is defined as a province, state, or other administrative subdivision within a country where cholera infections may be reported regularly (endemic) or where a cholera outbreak is occurring (epidemic), and includes areas with cholera activity within the past year, shows CDC.
The vaccine is not regularly recommended for most travelers from the United States, as most travelers do not visit areas with active cholera transmission.
No country or territory currently requires vaccination against cholera as a condition for entry.
Vaxchora® has been reported to reduce the chance of severe diarrhea in people by 90% at 10 days after vaccination and by 80% at 3 months after vaccination. The safety and effectiveness of Vaxchora® in pregnant or breastfeeding women is not yet known, and it is also not known how long protection lasts beyond 3 – 6 months after getting the vaccine. Side effects from Vaxchora® are uncommon and may include tiredness, headache, abdominal pain, nausea and vomiting, lack of appetite, and diarrhea.
Dukoral®, ShanChol®, and Euvichol-Plus®/Euvichol®
|Photo: International Vaccine Institute|
Three other oral inactivated, or non-live cholera vaccines are available: Dukoral (manufactured by SBL Vaccines); ShanChol (manufactured by Shantha Biotec in India), and Euvichol-Plus/Euvichol (manufactured by Eubiologics). These cholera vaccines are World Health Organization (WHO) prequalified but are not available in the U.S.
Cholera vaccines offer incomplete protection. Therefore, vaccination should never take the place of standard prevention and control measures.
|Cholera is mostly found in the tropics — in particular Asia, Africa, Latin America, India, and the Middle East. It's rare in the United States, but people can still get it. People who travel from countries where the infection is more common can bring cholera into the U.S. Some people in the U.S. have become sick from eating raw and undercooked shellfish from the Gulf of Mexico, cites Kidshealth.|
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