Coverage was comparable to or higher than that in other countries.
In 2013, the first government-led oral cholera vaccination (OCV) campaign in Haiti was implemented in Petite Anse and Cerca Carvajal. To evaluate vaccination coverage, barriers to vaccination, and adverse events following vaccination, we conducted a cluster survey. We enrolled 1,121 persons from Petite Anse and 809 persons from Cerca Carvajal, categorized by 3 age groups (1–4, 5–14,
Since October 2010, Haiti has endured one of the largest cholera epidemics ever recorded in a single country, accounting for 54% of all cholera cases and 41% of all cholera deaths reported to the World Health Organization (WHO) during 2010–2013 (
OCVs are increasingly being used as part of preemptive and reactive vaccination strategies (
In 2012, the first pilot OCV campaign was conducted in Haiti by 2 Haitian nongovernmental organizations (NGOs) in a rural area in Artibonite Department (target population for vaccination 50,000) and in an urban area in Port-au-Prince (target population 69,185) (
Areas selected for the first government-implemented oral cholera vaccination campaign in Haiti, 2013. Data source: Haiti Ministry of Health and Population, Centre National de l’Information Géo-Spatiale, and Institut Haïtien de Statistique et d’Informatique, OpenStreetMap.
To inform planning for future OCV campaigns in Haiti and other countries, we conducted a vaccination coverage survey. Compared with use of administrative coverage results, this method enables better assessment of the success of vaccination campaigns (evaluation of vaccine coverage, barriers to vaccination, and adverse events reported following vaccination).
We conducted a multistage cluster survey by using the 2011 household and population estimates provided by the Haitian Institute of Statistics and Information. The sampling frame consisted of 116 enumeration areas in Petite Anse and 25 in Cerca Carvajal. Enumeration areas are the primary sampling units, clearly delineated and mapped by the census bureau in Haiti, and are used as a sampling frame for major surveys in Haiti, including the Demographic and Health Survey. Sample size was calculated to estimate coverage by age group (1–4, 5–14 and
We selected 30 (26%) enumeration areas from Petite Anse and 18 (72%) from Cerca Carvajal by systematic random sampling without replacement. In each enumeration area, 20 households were selected by systematic sampling. Finally, in each selected household, 1 person in each age group, if available, was randomly selected (by use of a random number table) for interview.
A household was defined as a group of persons who ate together and lived under the same roof. Persons in households were eligible to participate if they 1) were
The protocol was approved by the national ethics committee in Haiti. It was classified as a program evaluation activity by the Centers for Disease Control and Prevention.
Team members (2 interviewers and 1 supervisor) who had experience with Demographic and Health Surveys were trained on survey and household selection methods, interviewing, use of smartphones for data collection, and use of global positioning system units. The survey was conducted during September 13–27, 2013, <1 month after campaign completion.
Interviews were initiated with the first household in 1 of the corners of the enumeration area noted on the global positioning system device. Subsequent households were selected by using the systematic method of traversing the enumeration area by moving in a clockwise manner and skipping households according to a precalculated sampling interval (estimated total number of households in cluster divided by 20). Contact was initiated with an adult, usually the female head of household, who was interviewed by use of a standardized questionnaire. Information collected included general household information: access to treated water and health care facilities, previous history of cholera infection in the household, awareness of the OCV campaign, and the number of eligible persons in the household who were vaccinated with OCV during the campaign and the number of doses received. Next, for each household, 1 person was randomly chosen from each of the 3 age groups for an in-depth interview (for younger children, the mother provided the information). Each interview collected information about the interviewee’s age, sex, previous history of cholera, number of OCV doses received during the campaign (documented by card or by recall if the card was not available), vaccine administration (route, location, and whether person spat out the vaccine), adverse events within 14 days of receipt of the first and second OCV dose, and general knowledge about OCV (duration of protection, need for other measures for protection against cholera). Those who had not received the first or second dose were asked their reasons for not being vaccinated. Interviewers asked all questions without prompting for answers. Interviews were conducted in Haitian Creole, and answers were recorded on smartphones.
Households were visited at least 2 times if no one was at home or if a randomly selected person was unavailable during the first visit. Selected households were not replaced if they were not eligible or if no one was at home (no response) after at least 2 attempted visits.
Estimated percentages and 95% CIs were calculated by using SAS-callable SUDAAN version 10.01 (RTI International, Research Triangle Park, NC, USA) to account for the finite population at the first stage cluster sampling. Statistical weights for each household were based on the sampling probabilities of the first 2 stages, and statistical weights for each person were based on the sampling probabilities of all 3 stages. For each area, we estimated 1- and 2-dose OCV campaign coverage (including 95% CI) by age group and sex. Satterthwaite-adjusted χ2 tests were used to compare coverage between subpopulations. For each area we also calculated rates of dropout between receipt of first and second vaccine doses, reports of any adverse events, and reasons for not receiving vaccine.
Of 960 visited households, 925 (96%) consented to participate (568 in Petite Anse, 357 in Cerca Carvajal). Of the participating households, 79% in Petite Anse and 46% in Cerca Carvajal were within a 15-minute walking distance of a drinking water source. In Petite Anse, the most common source of drinking water was bottled water or water purchased from a company (84%); in Cerca Carvajal, it was unprotected spring water (42%) and public piped water (34%).
For 56% and 21% of households in Petite Anse and Cerca Carvajal, respectively, the closest heath facility was located within 30 minutes of travel by the mode of transportation available in the household (walking, driving, motorcycle, or other). Overall, for 11% and 59% of the households in Petite Anse and Cerca Carvajal, respectively, the nearest health facility was >1 hour away. For ≈16% and 27% of households in Petite Anse and Cerca Carvajal, respectively, at least 1 household member had been infected with cholera during the past 2 years. At least 1 person had died of cholera in ≈3% of households (3.4% in Petite Anse and 3.2% in Cerca Carvajal).
Of the 568 households in Petite Anse and 357 in Cerca Carvajal, 511 (91%, 95% CI 87%–93%) and 335 (93%, 95% CI 89%–96%), respectively, were aware of the 2013 OCV campaign. Of those who were aware, the principal sources of information were social mobilizers who used megaphones, followed by health care workers and friends/family. In Petite Anse, 79.9% (95% CI 75.5%–83.7%) of households had at least 1 eligible person who had received 2 OCV doses; in Cerca Carvajal, 89% (95% CI 83%–93%) of households had at least 1 person who had received 2 doses. All eligible household members had received 2 OCV doses in 23% (95% CI 17.4%–28.7%) of households in Petite Anse and 37% (95% CI 31%–44%) of households in Cerca Carvajal.
A total of 1,121 and 809 persons in Petite Anse and Cerca Carvajal, respectively, who were eligible for vaccination were enrolled and categorized into 1 of the 3 age groups (
| Characteristic | Area | |
|---|---|---|
| Petite Anse, n = 1,121 | Cerca Carvajal, n = 809 | |
| Sex, no. (%) | ||
| M | 499 (43.1) | 407 (50.6) |
| F | 622 (56.9) | 402 (49.4) |
| Age, y, no. (%) | ||
| 1–4 | 206 (10.3) | 192 (13.8) |
| 5–14 | 353 (24.8) | 263 (35.0) |
|
| 562 (64.9) | 354 (51.1) |
| History of cholera, % (95% CI) | 38 3.5 (2.4–5.2) | 48 6.6 (4.5–9.6) |
| No. doses Received | Area, % (95% CI) | ||||||
|---|---|---|---|---|---|---|---|
| Petite Anse | Cerca Carvajal | ||||||
| Total, n = 1,118 | Male, n = 497 | Female, n = 621 | Total, n = 808 | Male, n = 407 | Female, n = 401 | ||
| Total | |||||||
| 2 | 62.5 (57.9–66.9) | 59.8 (53.9–65.5) | 64.5 (58.8–69.7) | 76.8 (71.1–81.8) | 69.0 (60.4–76.4) | 84.9 (80.0–88.8) | |
| 1 | 6.6 (4.9–8.9) | 7.1 (4.7–10.4) | 6.3 (3.8–10.2) | 7.0 (4.7–10.5) | 10.0 (6.3–15.4) | 4.0 (2.4–6.8) | |
| 0 | 30.9 (26.8–35.3) | 33.1 (27.6–39.1) | 29.2 (24.8–34.1) | 16.1 (12.4–20.6) | 21.1 (15.3–28.3) | 11.0 (7.9–15.2) | |
| Age group, y | |||||||
| 1–4 | n = 206 | n = 102 | n = 104 | n = 191 | n = 91 | n = 100 | |
| 2 | 67.9 (60.2–74.8)† | 63.9 (52.8–73.6) | 71.8 (62.5–79.5) | 81.6 (72.9–88.0)† | 87.5 (75.5–94.1) | 76.1 (63.1–85.6) | |
| 1 | 2.4 (0.8–6.9) | 4.5 (1.4–13.4) | 0.3 (0.0–2.4) | 5.8 (2.7–12.0) | 3.5 (0.8–13.9) | 7.9 (3.2–18.5) | |
| 0 | 29.7 (23.3–37.0) | 31.6 (22.3–42.5) | 27.9 (20.3–37.1) | 12.6 (7.9–19.6) | 9.1 (4.1–18.8) | 16.0 (9.1–26.5) | |
| 5–14 | n = 351 | n = 163 | n = 188 | n = 263 | n = 148 | n = 115 | |
| 2 | 77.9 (71.7–83.0)† | 75.5 (65.1–83.6) | 79.8 (72.4–85.6) | 83.8 (75.0–89.9)† | 76.5 (63.6–85.9) | 92.9 (85.1–96.7) | |
| 1 | 5.8 (3.7–9.0) | 6.1 (3.1–11.3) | 5.6 (3.0–10.3) | 5.5 (2.8–10.8) | 8.5 (4.0–17.2) | 1.8 (0.6–5.5) | |
| 0 | 16.3 (12.1–21.7) | 18.4 (11.5–28.2) | 14.6 (9.8–21.2) | 10.7 (6.2–17.7) | 15.0 (8.3–25.5) | 5.4 (2.0–13.7) | |
|
| n = 561 | n = 232 | n = 329 | n = 354 | n = 168 | n = 186 | |
| 2 | 55.7 (50.0–61.3)† | 52.5 (44.8–60.0) | 58.0 (50.7–65.0) | 70.8 (63.9–76.9)† | 57.9 (47.4–67.8) | 82.7 (75.7–88.0) | |
| 1 | 7.6 (5.3–10.9) | 7.9 (4.5–13.6) | 7.4 (4.0–13.2) | 8.4 (5.3–13.1) | 12.9 (7.6–21.1) | 4.3 (2.1–8.6) | |
| 0 | 36.7 (31.5–42.1) | 39.6 (32.4–47.2) | 34.6 (28.7–41.0) | 20.8 (15.7–27.0) | 29.2 (20.5–39.7) | 13.0 (8.6–19.2) | |
*Vaccination status was assessed from special cards distributed to document doses administered during the campaign, if available, or by recall; in every selected household, 1 person was randomly selected from each age group. Statistical analyses accounted for the weights and the study design.
†Design effect (DE) and estimated intraclass correlations (ICC) = (DE−1)/(b−1), where b is the average number of responses per cluster. DE is based on accounting for clustering only (The finite population correction and weighting are ignored). Petite Anse: age group: 1–4 y, DE = 1.3 and ICC = 0.05; 5–14 y, DE = 1.4 and ICC = 0.04;
In Petite Anse, two thirds of respondents reported having received OCV at home (66.4%, 95% CI 58.5%–73.5%) and nearly a quarter at mobile posts (23.9%, 95% CI 18.1%–30.8%). In Cerca Carvajal, almost half of respondents reported having received OCV at mobile posts (49.6%, 95% CI 41.5%–57.8%) and 19.4% (95% CI 15.3%–24.3%) at health centers. About 7% and 5% of respondents in Petite Anse and Cerca Carvajal, respectively, reported spitting out part of the first dose because of its bad taste; <5% in both areas reported spitting out part of the second OCV dose.
Of 1,459 respondents who had received at least 1 OCV dose, almost one third (34% in Petite Anse, 33% in Cerca Carvajal) reported that they thought OCV alone was enough to protect them from cholera. Most (73%) respondents did not know the duration of protection provided by OCV; <2% thought protection lasted 3–5 years, and 16% in Petite Anse and 10% in Cerca Carvajal thought protection lasted a lifetime.
Among respondents who reported having received at least 1 dose of OCV, minor adverse events following the first dose were reported by 8% and following the second dose by almost 5%. The most commonly reported adverse events were nausea, vertigo, and abdominal pain (
| Adverse event | Petite Anse, no. (%) | Cerca Carvajal, no. (%) |
| First dose | ||
| No. who received dose | 768 | 691 |
| Total events reported | 68 (7.9; 95% CI 6.0–10.3) | 56 (8.0; 95% CI 5.4–11.7) |
| Common events reported† | ||
| Nausea | 20 (2.6) | 17 (2.5) |
| Vertigo | 15 (2.0) | 11 (1.6) |
| Abdominal pain | 13 (1.7) | 17 (2.5) |
| Weakness/fatigue | 11 (1.4) | 4 (0.6) |
| Diarrhea | 9 (1.2) | 9 (1.3) |
| Vomiting | 5 (0.7) | 5 (0.7) |
| Bloating | 3 (0.4) | 7 (1.0) |
| Fever | 8 (1.0) | 5 (0.7) |
| Headache | 2 (0.3) | 4 (0.6) |
| Rash | 4 (0.5) | Not reported |
| Second dose | ||
| No. who received dose | 697 | 637 |
| Total events reported | 35 (4.7; 95% CI 3.0–7.3) | 29 (4.1; 95% CI 2.4–6.8) |
| Common events reported‡ | ||
| Vertigo | 6 (0.9) | 7 (1.1) |
| Nausea | 7 (1.0) | 5 (0.8) |
| Abdominal pain | 6 (0.9) | 9 (1.4) |
| Vomiting | 1 (0.1) | 2 (0.3) |
| Diarrhea | 2 (0.3) | 4 (0.6) |
| Fever | 4 (0.6) | 3 (0.5) |
| Weakness/fatigue | 4 (0.6) | 1 (0.2) |
| Headache | 3 (0.4) | 3 (0.5) |
| Rash | 6 (0.9) | Not reported |
| Bloating | 2 (0.3) | Not reported |
*The categories for adverse events are not mutually exclusive as participants had the option to report multiple adverse events. †Denominator incudes persons who received the first dose. Percentages are unweighted for the purpose of description only. ‡Denominator includes persons who received the second dose. Percentages are unweighted for the purpose of description only.
| Reason | Petite Anse, no. ( %) | Cerca Carvajal, no. ( %) |
|---|---|---|
| First dose | ||
| No. who did not receive dose | 348 | 117 |
| Absent during the campaign | 141 (40.5) | 63 (53.8) |
| Did not hear about the vaccination activities | 41 (11.8) | 15 (12.8) |
| Busy/no time | 34 (9.8) | 7 (6.0) |
| Sick during the campaign | 14 (4.0) | 4 (3.4) |
| Didn’t think vaccination was important/necessary | 20 (5.7) | 2 (1.7) |
| Don’t think vaccines are safe/vaccines can harm | 10 (2.9) | 2 (1.7) |
| Vaccines not available | 5 (1.4) | 4 (3.4) |
| Didn’t know when or where to go | 6 (1.7) | 2 (1.7) |
| Clinic closed/vaccinator not there/vaccinator refused to vaccinate | 6 (1.7) | 2 (1.7) |
| Other | 71 (20.4) | 16 (13.7) |
| Second dose† | ||
| No. who did not receive dose | 73 | 54 |
| Absent during second campaign | 21 (28.8) | 13 (24.1) |
| Clinic closed/vaccinator refused to vaccinate | 5 (6.8) | 1 (1.9) |
| Busy/no time | 4 (5.5) | 11 (20.4) |
| Bad experience/ adverse event after first dose | 6 (8.2) | 2 (3.7) |
| Did not know needed a second dose | 3 (4.1) | 1 (1.9) |
| Sick during the campaign | 2 (2.7) | Not reported |
| Didn’t know when or where to go | Not reported | 2 (3.7) |
| Forgot to go | 2 (2.7) | 1 (1.9) |
| Vaccines not available | 1 (1.4) | 7 (13.0) |
| Other | 29 (39.7) | 9 (16.7) |
*Categories are mutually exclusive because respondents were allowed to give only 1 primary reason. Percentages are unweighted for the purpose of description only. †Of those who received the first dose.
We report OCV coverage, barriers to vaccination, and adverse events after the first government-implemented OCV campaign in Haiti. The overall rates of 2-dose OCV coverage in rural Cerca Carvajal (77%) and urban Petite Anse (63%) were lower than the reported administrative coverage. Potential explanations could be the inaccurate population denominators used to calculate administrative coverage because the most recent census data were for 2003. In addition, several persons came from other areas to receive the vaccine, especially in Petite Anse, a crowded urban area, leading to overestimation of administrative coverage. Furthermore, the splitting and delaying of the second round of vaccination in Petite Anse created some confusion among the population regarding the vaccination dates and could have contributed to the high dropout rates. Nevertheless, the 2-dose OCV coverage achieved in Haiti is considered acceptable because herd immunity after 2-dose coverage with Shanchol as low as 28% has been reported (
Our results are comparable to those reported after a pilot OCV vaccination campaign conducted in 2012 by 2 NGOs in Haiti, for which coverage was 77% in rural Bocozel (
OCV coverage was much lower among persons
Most respondents did not know the duration of protection provided by the vaccine, and almost one third thought that vaccine alone would be enough to protect them from cholera. This poor knowledge about the vaccine may result from limited messaging about the vaccine during the campaign; most of the information was spread through pamphlets, which probably were of limited usefulness because of low literacy rates in the target communities. These findings are concerning because persons who believe they are completely protected from cholera after vaccination might abandon protective behavior such as treating drinking water and practicing good hygiene. OCV campaigns should offer an opportunity to promote hygiene and safe water and food practices; an OCV campaign conducted in 2012 by an NGO in rural Haiti included a strong cholera and WASH education component and was associated with improved cholera knowledge and hygiene practices (
Although the 200,000 OCV doses for the 2013 campaign were purchased directly from the manufacturer by the United Nations Children’s Fund, future OCV for use in cholera-endemic and -epidemic settings will be mainly obtained through the OCV stockpile managed by the International Coordinating Group and the Global Task Force on Cholera Control (
As has been noted for other Shanchol campaigns (
This survey has 2 main limitations. Only half of respondents who received both OCV doses in Petite Anse and 70% of those in Cerca Carvajal could document OCV vaccination by card. Therefore, in some instances we based vaccine status on a patient’s verbal report, which could have led to overestimation of vaccine coverage. However, the extent of this bias was probably limited because the survey was conducted shortly after the campaign, and respondents correctly identified campaign dates and route of OCV administration. Second, overestimating coverage in the sample size calculation and underestimating the design effect in Cerca Carvajal contributed to the wide confidence intervals. However, we have reported the estimated design effect caused by clustering and the estimated intraclass correlation (
In conclusion, coverage rates after the first government-implemented OCV campaign in Haiti were acceptable. As part of the national plan for the elimination of cholera, results from this survey would be essential for planning future OCV campaigns in Haiti to reach those who remain nonvaccinated. Given the lack of accurate data about target population estimates and high vaccine demand from nearby areas, it may be useful to overestimate required vaccine doses to improve vaccination coverage and avoid running out of vaccine during future campaigns. Printing enough vaccination cards and emphasizing the value of keeping the card and bringing it back when receiving the second vaccine dose are needed. Vaccination sessions should be tailored to reach persons who work during the day and men in general. Furthermore, OCV campaigns should be coordinated with WASH activities to ensure a comprehensive approach to cholera control and prevention and to promote the elimination of cholera from Haiti.
Results from this study were partially presented at the 49th US–Japan Conference on Cholera and Other Enteric Bacterial Infections; 2015 Jan 14–16; Gainesville, Florida, USA.
We thank Yves Gaston Deslouches, Roc Magloire, and the Institut Haitian de l’Enfance (especially Michel Cayemittes Alexandre Canez, Ferdinand Marseille, Marie-Rose Jeannot, Lutherson Vilus, Claude Val, Adiles David Brignol, Lovelie Dorleus, Marie Emmanuelle Casimir, Sherly Gay, Nathalie Cadet, Kettia Negaud, Valerie Jefferson, Madaline Noel, and Anne Esther Variste) for data collection. We also thank Alex Pavluck for programming of the questionnaire on the smartphones and provision of the smartphones for the survey; Kathy Middleton, Nicolas Schaad, Catherine Yen, Vance Dietz, Tracie Wright, Janell Routh, and Stanley Juin for their valuable support and input throughout the study; and the people of Haiti who participated in the survey.
Dr. Tohme is a medical epidemiologist and the lead of the Haiti team in the Global immunization Division at the Centers for Disease Control and Prevention, in Atlanta, Georgia. Her main research interests include evaluation of vaccination campaigns, vaccination coverage surveys, assessment of the effect of new vaccines, and vaccine-preventable disease surveillance.