Table 2. Characteristics and main findings of post-licensure oral cholera vaccination campaign studies, 1997–2014.
| Vaccine and year of the campaign | Site | Setting | Type and purpose of the vaccination campaign | Eligibility criteria | Target population | Coverage |
Main findings | ||
|---|---|---|---|---|---|---|---|---|---|
| Received 1st dose, no. (%) | Received 2nd dose, no. (%) | ||||||||
| Dukoral® | |||||||||
| 1997 | Adjumani district, Uganda | Refugee camp, rural | Pre-emptive vaccination to assess feasibility in a stable refugee camp setting16,17 | ≥ 1 year old | 44 000 | 35 613 (81) | 27 607 (62) | Oral cholera vaccination of a large refugee population is feasible.16 During a cholera epidemic in the area the following year, cholera attack rates were 0.59% in the non-refugee Ugandan villages, 0.04% in the 30 non-vaccinated refugee camps and 0.00% in the six vaccinated refugee camps17 | |
| 2000 | Mayotte Island, Comoros | Urban and rural | Pre-emptive vaccination campaign to prevent a cholera epidemic18 | NA | 145 000 | NA | 93 000 (64) | NA | |
| 2003–2004 | Beira, Mozambique | Urban | Pre-emptive vaccination in an endemic area with seasonal outbreaks. Effectiveness study in an HIV-endemic sub-Saharan African site20,21 | Non-pregnant women, ≥ 2 years old children | 19 550 | 14 164 (72) | 11 070 (57) | Mass vaccination was feasible but required considerable logistic support and planning.20 One or more doses conferred 78% protection (95% CI: 39–92) against cholera during the year post vaccination21 | |
| 2004 | South Darfur, Sudan | Refugee camp, rural | Pre-emptive vaccination to assess feasibility during the acute phase of an emergency (i.e. refugee camp of internally displaced persons)22,23 | ≥ 2 years old | 45 825 | 42 502 (93) | 40 330 (88) | Although planning and implementation requirements were significant, the campaign was successful because of the strong support and commitment of the refugee community and collaborators22,23 | |
| 2005 | Aceh, Indonesia | Site of internally displaced persons | Pre-emptive vaccination to assess feasibility during the acute phase of an emergency (i.e. post-tsunami)23,24 | ≥ 2 years old | 78 870 | 62 505 (79) | 54 627 (69) | Challenges in the coordination, heavy logistics and frequent aftershocks complicated and delayed implementation. Difficulties in maintaining a cold chain resulted in 11.7% vaccine losses23,24 | |
| 2009 | Zanzibar, the United Republic of Tanzania | Urban and rural | Pre-emptive vaccination in an endemic area with seasonal outbreaks. Effectiveness study to measure direct and indirect protection26–28 | Non-pregnant women, ≥ 2 years old children | 48 178 | 27 678 (57) | 23 921 (50) | Confirmed direct vaccine effectiveness of 79% (95% CI: 47–92). First study to show vaccine herd protection in an African setting: 75% (95% CI: 11–93%) indirect protection in the higher coverage group compared with the lower coverage group.26 No evidence of a harmful effect of gestational exposure to the vaccine.27 First use of personal digital assistants for direct data entry during a survey enumeration and mass vaccination28 | |
| ORC-Vax™ and mORC-Vax™ | |||||||||
| 1998–2012 | Viet Nam | Endemic urban and rural areas | Pre-emptive and reactive vaccinations of children integrated into the country’s public health programme33 | Non-pregnant women, ≥ 1 year old children | ≈10.9 million doses | NA | NA | Viet Nam is the only country in the world to regularly use oral cholera vaccinations. Since 1997, the number of cholera cases in Viet Nam has declined, in association with increased vaccination use as well as improvements in socioeconomic and water and sanitation conditions33 | |
| 1998 and 2000 | Hue, Viet Nam | Urban and rural | Pre-emptive vaccination campaign in a cholera-endemic area. Study to assess long term effectiveness30,31 | Non-pregnant women, ≥ 1 year old children | 149 557 (1998) and 137 082 (2000) | In 1998: 125 135 (84) and in 2000:104 706 (76) | In 1998:118 703 (79) and in 2000:103 226 (75) | Mass immunization is feasibly administered through the public health system.30 Direct vaccine effectiveness 3 to 5 years after vaccination was 50% (95% CI: 9–63)31 | |
| 2008 | Hanoi, Viet Nam | Urban | Reactive vaccination campaign during an on-going outbreak32 | Non-pregnant women, ≥ 1 year old children | ≈370 000 > 10 years old | NA | ≈80% vaccinated | Protective effectiveness of 76% (95% CI: 5–94). First study to document reactive use of oral cholera vaccination during an outbreak32 | |
| Shanchol™ | |||||||||
| 2011 | Odisha, India | Rural | Pre-emptive vaccination campaign and feasibility study34 | Non-pregnant woman, ≥ 1 year old | 51 488 | 31 552 (61) | 23 751 (46) | Feasible to vaccinate using governmental set-up34 | |
| 2011 | Dhaka, Bangladesh | Endemic urban areas | Pre-emptive vaccination. Cluster randomized study with three arms: vaccine, vaccine plus safe water and hand washing practice and no intervention35 | Non-pregnant women, ≥ 1 year old children | 172 754 | 141 839 (82) | 123 666 (72) | Feasible to use the national immunization set-up.35 On-going study of vaccine effectiveness | |
| 2012 | Port-au-Prince, Haiti | Urban | Reactive vaccination campaign. Pilot study36 | ≥ 1 year old children | 70 000 | 52 357 (75) | 47 540 (68) | Effort, community mobilization and organizational capacity needed for a successful campaign where there were logistical and security challenges36 | |
| 2012 | Bocozel and Grand Saline, Haiti | Rural | Reactive vaccination campaign. Pilot study37–40 | ≥ 1 year old children | ≈50 000 | 45 417 | 41 238 (Estimated 77–79% in Bocozel and 63% in Grand Saline) | The campaign integrated with the other components of cholera control was found to be feasible and acceptable37–40 | |
| 2012 | Choiseul and Shortland, Solomon Islands | Rural | Pre-emptive vaccination campaign near an area with a cholera outbreak41 | Children 1–14 years old in high-risk areas | NA | 11 888 | 11 318 | NA | |
| 2012 | Tak Province, Thailand | Refugee camps, rural | Pre-emptive vaccination campaign with a knowledge, attitudes and practices survey42 | Non-pregnant women, ≥ 1 year old children | 43 968 | 36 325 (83) | 26 753 (61) | First use of Shanchol™ in a stable refugee camp setting42 | |
| 2012 | Boffa and Forecariah regions, Guinea | Rural | Reactive vaccination campaign during an on-going outbreak and feasibility study43–45 | ≥ 1 year old children | ≈209 000 (≈163 000 in Boffa and ≈46 000 Forecariah) | 172 544 | 143 706 (Based on administrative population figures, 68% in Boffa and 51% in Forecariah. Household survey immediately after campaign 76%)43 | First use of Shanchol™ in sub-Saharan Africa. The campaign was successful despite short preparation time, remote rural setting and highly mobile population.43,44 Protective effectiveness of 87% (95% CI: 56–96)45 | |
| 2013 | Maban county, South Sudan | Refugee camps, rural | Pre-emptive vaccination campaign in an area with escalating Hep E outbreak46,47 | ≥ 1 year old children | 146 317 | NA | 132 000 (> 85% by survey) | The campaign was successful despite logistical challenges46,47 | |
| 2013 | Petite Anse and Cerca Carvajal, Haiti | Urban and rural | Pre-emptive vaccination campaign in a cholera-endemic areaa | ≥ 1 year old children | > 110 000 | 113 045 | 102 250 | NA | |
| 2014 | South Sudan | Internally displaced persons camps | Pre-emptive vaccination campaign48 | Non pregnant women, ≥ 1 year old children | 152 000 | 125 311 (72) | 76 088 (awaiting coverage surveys) | Humanitarian crisis. First use of global OCV stockpile. Fixed and mobile teams. Second round in one site was co-administered with meningitis vaccine48 | |
CI: confidence interval; Hep E: Hepatitis E; NA: information not available; OCV: oral cholera vaccination.
a Information obtained through personal communications with Kathryn Alberti, UNICEF, New York, USA.