Cholera is an important public health problem globally and results in an estimated 2.9 million cases of disease and 95,000 deaths annually. Cholera is endemic in Malaysia with incidence rate ranged between 0.01-0.8 per 100,000 population in the last five years (2014-2019). High incidence rates in 2015 and 2018 were due to outbreaks which occurred in Sabah with 235 and 163 cases reported in the respective years. It is an acute enteric infection caused by the ingestion of the bacterium Vibrio cholerae O1 or O139. The disease is transmitted through the faecal-oral route and through ingestion of contaminated water or food. It can cause severe diarrhoea with or without vomiting. Death can occur in a few hours due to dehydration, electrolyte imbalance, acidosis, shock, hypoglycaemia and renal failure.
Cholera is treated with oral rehydration salts, intravenous fluids and other supportive measures. Appropriate antibiotics may be given to severe cases to diminish the duration of diarrhoea, reduce the volume of rehydration fluids needed and shorten the duration of Vibrio excretion. It is controlled from spreading by public health measures and prevented by good hygiene, good sanitation and clean water supply.
The use of vaccines has now been advocated as an additional measure of lowering the risk of acquiring and transmitting the infection. However, the vaccine should not be used to treat a cholera infection. No adverse effects have been noted in pregnant women or the immunocompromised who were given the vaccine. However, it should only be used if the benefit outweighs the risk.
It is an oral vaccine consisting of killed whole-cell V. cholerae O1 with purified recombinant B subunit of cholera toxin (WC/rBS). The protection starts approximately 1 week after ingestion of the 2nd dose and gives a demonstrated protection of 85-90% at 6 months in all age groups, and of 62% at 1 year among adults.
2. Vaxchora, PaxVax, Redwood City, California
Live attenuated oral cholera vaccine (lyophilised CVD 103-HgR). It is approved in the USA only for use in travelers to cholera affected areas.
Vaccines Available in Malaysia
- AJ Biologics Sdn Bhd/ Valneva, Sweden
- The vaccine is supplied in 3mL single-dose vials, each with a sachet of sodium bicarbonate buffer.
- Each dose of the vaccine should be administered in 150mL of water (75mL for children aged 2-6 years) mixed with the buffer.
- It cannot be administered to children aged <2 years.
- 2 doses are given orally with a minimum of 1 week and a maximum of 6 weeks apart.
- Vaccinees must be informed of the necessity to fast for 2 hours before and 1 hour after ingesting the dose.
- The reconstituted vaccine should be drunk within 2 hours.
Table 2.1 Characteristics of Cholera Vaccine Dukoral.PNG
The most frequently reported adverse effects include gastrointestinal symptoms such as stomach pain, diarrhoea, nausea & vomiting. Other adverse effects such as headache, dizziness, fever, rash, itching, runny nose & cough have been reported.
Target Groups in Malaysia
- Travelers to areas in which there is a recognised risk of exposure to cholera. All travelers to cholera-affected areas should follow safe food and water precautions and proper sanitation and personal hygiene measures as primary strategies to prevent cholera.
- The course of vaccination should be completed at least one week before travel.
- During humanitarian crises with high risk of cholera, and during cholera outbreaks
- The vaccine is not routinely recommended for travelers who are not visiting areas of active cholera transmission*.
- *An area of active cholera transmission is defined as a province, state, or other administrative subdivision within a country with endemic or epidemic cholera caused by toxigenic V. cholerae O1 and includes areas with cholera activity within the last year that are prone to recurrence of cholera epidemics; it does not include areas where only rare imported or sporadic cases have been reported.
Implications for Healthcare Workers (HCWs)
Evidence for Effectiveness
- Both available formulations of the vaccines were effective in inducing a vibriocidal antibody response
- For recipients ages 5 to 15, the cholera vaccine was 52% effective in protecting against all cholera and 71% effective in protecting against severe episodes. For adults, the vaccine protective efficacy was 59% against all cholera episodes.
- Ali, M., Nelson, A. R., Lopez, A.L, Sack, D. A. (2015). Updated global burden of cholera in endemic countries. PLoS Negl Trop Dis, 9, e0003832 https://doi.org/10.1371/journal. pntd.0003832
- Centers for Disease Control and Prevention (CDC). (2016). Department of Health and Human services. Advisory Committee on Immunization Practices. Summary Report. https://www. cdc.gov/vaccines/acip/meetings/downloads/min-archive/min-2016-06.pdf
- Centers for Diseases Control and Prevention (CDC). (2017). Recommendations of the Advisory Committee on Immunization Practices for Use of Cholera Vaccine. MMWR (66)18: 482-485. https://www.cdc.gov/vaccines/acip/meetings/downloads/min-archive/min-2016-02.pdf Malaysian National Centre of Adverse Drug Reactions database. https://npra.gov.my/ Ministry of Health of Malaysia (MOH). (2011-2019). Health facts: Incidence rate and mortality rate of communicable diseases. https://www.moh.gov.my/index.php/pages/view/58 Ministry of Health of Malaysia (MOH). (2016 &2019). Health Indicators: Indicators for Monitoring and Evaluation of Strategy Health for All. https://www.moh.gov.my/index.php/ pages/view/58
- Summary of WHO Position Paper. (2019). Immunisation of Healthcare workers. https://www. who.int/immunization/policy/Immunization_routine_table4.pdf
- World Health Organization (WHO). (2005). Cholera. WHO position paper. Weekly Epidemiol Rec 81: 297-308. http://www.who.int/wer
- World Health Organization. (2010). Cholera vaccines. WHO position paper. Weekly Epidemiol Rec 85: 117-128. http://www.who.int/wer