Oral Cholera Vaccination in Emergencies: Experiences from Freetown, Republic of Sierra Leone

Dr Denis Marke, CH/EPI Program Manager at the Sierra Leone Ministry of Health shared his experiences from a recent natural disaster at the WHO African Regional Immunization Technical Advisory Group meeting in Johannesburg, 5-8 December 2017. Below find his observations.

Heavy rains occurred in the early hours of 14th August 2017 that resulted in flash floods and mudslides that affected three communities (Sugar Loaf, Motomeh, and Kaningo) in the Western Area districts. The mudslides and flash floods blocked water ways and contaminated water sources in several low lying communities of Freetown, the capital city. Both mudslides and flooding destroyed houses, killing many people and displacing thousands of people. In addition, water and sewerage infrastructure were damaged.

Data collected from the emergency operations centre set up to manage the incident showed that 496 people died (168 females, 171 males of which 157 children). An additional 5,905 people were registered as displaced. The WHO assessment classified the incident as a Grade 1 emergency.

In analysis of health risks likely to affect the displaced people, cholera was ranked high on the account that there had been no confirmed Cholera outbreak since 2012. All historical outbreaks of cholera were analyzed and documented to a) Sierra Leone had had a history of 9 cholera outbreaks between 1970-2012; b) large outbreaks with case counts above 20,000 had occurred in 1994/5 and 2012; c) improved case-fatality ratios due to improvements in Health Worker skills and competencies in case management; d) almost all cholera epidemics occurred or peaked in the rainy season and e) shortening inter-epidemic periods, and thus another Cholera outbreak had been predicted since 2016.

A preventive Oral cholera vaccination concept for prevention of Cholera in Sierra Leone as part of the interventions in the emergency was mooted by WHO as the lead agency supporting the emergency response. A technical proposal for Oral Cholera vaccination was developed, presented and discussed at the Emergency Operations Centre and approved by the Ministry of Health and Sanitation. Support to implement the Oral Cholera vaccination was received from the Global Outbreaks and Alert Network, ICG, GAVI, UKaid, PIH and MSF.

Preparations for Oral Cholera vaccination broke records in terms of speedy planning and implementation. The OCV concept note was developed and approved by the MOH in 9 days. A proposal and request for OCV was approved by ICG in 72 hours. And the approved OCV doses were delivered in-country in 10 days. The national Regulatory Authority gave a waiver of vaccine registration, on the account of WHO pre-qualification and procurement through UNICEF supply division, and the OCV campaign conducted within 7 days of vaccine receipt. Notably, this was the FIRST cholera vaccination campaign EVER conducted in Sierra Leone and FIRST for that matter in an emergency.

The Objective of the OCV campaign was to provide two OCV vaccination doses to at least 95% of populations above 1 year of age living in communities affected by floods and mudslides and vulnerable populations in slums. The campaign took place in two rounds conducted on 14th – 19th September 2017 (first dose) and 5th – 10th October 2017 (second dose).

The Target Population for the Oral Cholera vaccination was all people aged >1 year resident in flood affected and slum communities of Western Area (Urban/Rural). Based on population projections for the affected communities, the estimated target was planned as 539,692 individuals.

The Oral Cholera vaccine delivery strategy was based on experiences from Oral Polio SIAs and it included four approaches: 1) House to House; 2) Schools-based temporary vaccination sites; 3) Fixed site at 22 affected Peripheral Health Units and 4) Outreach/mobile vaccination posts in camps of displaced people.

Overall the OCV Campaign reached 96.1% of the target population in the first round and 100% in the second round.  Post campaign independent monitoring documented that the overall coverage was slightly lower than was reported using the administrative reporting system. Independent monitors also documented that the main reasons for accepting vaccination were a) health information given out by health workers about the dangers of cholera, b) assurance from health workers and community leaders that the vaccine was safe. Unlike all previous Polio vaccination campaigns, radio, community social mobilizers, health workers and TV were the main source of information about the campaign.

Where non-vaccinated people were found, the major reasons were a) Poor H2H team movements and penetration; b) absence of beneficiary; c)  Acute sickness and d) unaware of vaccination dates/time. The poor team performance was attributed to the challenging terrains and clogged roads.

To verify community coverage, a post OCV Verification Survey was conducted from 21- 29 October 2017 in 140 clusters (enumeration areas). In total 2,908 Households studied and 6,987 individuals interviewed. Among people vaccinated 31.1% received only one dose and 68.6% received two doses.

In addition to oral cholera vaccination, Sierra Leone a) provided standard case definitions for cholera and trained camp commanders in the displaced populations to improve early detection of suspected cases; b) Updated and disseminated case management guidelines before conducting refresher training of case-management teams; c) Procured and prepositioned transport media for stool samples to be taken from suspected cases; d) Stock-piled and prepositioned at least 1 cholera case management kit; e) developed and disseminated IEC materials before conducting community engagement meetings with 48 Ward Councilors, 100 Market women, 120 teachers, 60 religious leaders and 40 CBO staff and f) Assured inclusion of cholera preparedness and response as a standing agenda of all EOC coordination mechanisms

This preventive effort not only kept cholera out of the area but also strengthened capacity to respond to future outbreaks and preventive campaigns. Coordination mechanisms have been established, vaccinators have been trained. Behavior change communication messages have been developed and a monitoring mechanism was tested to verify post-intervention results.  Coming out of the Ebola epidemic of a few years ago, Sierra Leone is encouraged by its new abilities to respond to emergencies and prevent outbreaks.

We acknowledge the assistance of Dr William Baguma MBABAZI, Medical Epidemiologist, EPI/WHO Sierra Leone, in the preparation of this posting.


2 thoughts on “Oral Cholera Vaccination in Emergencies: Experiences from Freetown, Republic of Sierra Leone

  1. Hello,

    My name is Christina Shaw and I run the Stop Cholera website (https://www.stopcholera.org/), created under the DOVE Project which is led by Dr. David Sack. We came across ‘Oral Cholera Vaccination in Emergencies: Experiences from Freetown, Republic of Sierra Leone’ and feel that it would be a great addition to our blog.

    We have cross-posted stories on our blog from NPR, Harvard Humanitarian Initiative’s Advanced Training Program on Humanitarian Action, and others and you can see an example of what that looks like here: https://www.stopcholera.org/blog/yemen%E2%80%99s-cholera-crisis-fighting-disease-during-armed-conflict. You would get full credit and we would link directly to your website. Please let me know if you would allow us to promote this great piece via cross-posting!

Leave a Reply

Your email address will not be published. Required fields are marked *