L’utilisation de l’approche CTC: quel impact sur la couverture vaccinale lors de la campagne préventive de vaccination contre la méningite A avec le MenAfriVac au Togo en 2014 ?

Abstract

IntroductionUne campagne de vaccination contre la méningite A avec le vaccin MenAfriVac a été organisée dans les quatre régions septentrionales du Togo du 28 novembre au 07 décembre 2014. L'approche CTC a été utilisée pour la première fois à une grande échelle pour la campagne de vaccination dans dix districts sanitaires du Togo. L'objectif de cette étude était d'estimer la couverture vaccinale et, de déterminer l'effet de l'utilisation de la Chaîne à Température Contrôlée (CTC) sur ces couvertures vaccinales.MéthodesL'enquête s'est déroulée du 9 au 14 mars 2015, soit environ 3 mois après la fin de la campagne de vaccination dans ces quatre régions. Le sondage en grappe à deux degrés stratifiés selon les régions a été utilisé. Dans 10 districts, le Togo a fait le choix d'utiliser le vaccin MenAfriVac en CTC.RésultatsAu total, 2707 ménages ont été enquêtés et 9082 personnes âgées de 1 à 29 ans ont été interviewées. L'âge moyen des personnes enquêtées était de 11,8±7,7 ans et le sex-ratio (H/F) de 1,01. Le nombre moyen de personnes par ménage était de 5,7 et celui des personnes de 1 à 29 ans ciblées par la campagne était de 3,4. Sur les 9082 personnes enquêtées, 8889 (98%) étaient vaccinées. En analyse multivariée, les facteurs associés à la couverture vaccinale avec le MenAfrivac étaient la résidence dans la zone au moment de la campagne (aOR = 4,52 ; 95%IC = [4.07 - 4.97]) et le fait d'être informé de la campagne avant son démarrage (aOR=2,42 ; 95%IC = [2.05 - 2.80]). Par contre, la couverture vaccinale n'était pas différente selon la zone ayant utilisé l'approche CTC ou non (aOR=0,09 ; 95%IC = [-0,27-0,45]). Deux cent sept personnes interrogées (2,3%) ont déclaré avoir eu une Manifestation Adverse Post Immunisation (MAPI) après l'administration du vaccin. Il s'agissait surtout de MAPI mineures à type de fièvre, d'abcès et de gonflement au point d'injection.ConclusionLes résultats de cette enquête montrent que l'utilisation de la CTC dans un pays à ressources limitées comme le Togo n'a pas eu un effet négatif sur les couvertures vaccinales. En effet, il n'y avait pas de différence entre la couverture vaccinale dans les zones CTC et celles non CTC. Il importe de capitaliser l'expérience acquise pour l'utilisation des vaccins du Programme Elargi de Vaccination avec l'approche CTC surtout dans les pays à ressources limitées confrontés à la disponibilité de la chaîne de froid.BackgroundA vaccination campaign against meningitis A using MenAfriVac vaccine was implemented in the four regions of northern Togo from 28 November to 7 December 2014. CTC approach was first used on a large scale in a vaccination campaign in ten health districts in Togo. This study aims to estimate the immunization coverage and to determine the effect of Controlled Temperature Chain (CTC) approach on these immunization coverages.

Status of the Rollout of the Meningococcal Serogroup A Conjugate Vaccine in African Meningitis Belt Countries in 2018

“…The CTC approach was first used on a large scale in 2014 in a vaccination campaign in 10 health districts in Togo. A survey carried out in Togo showed that the use of this approach did not have a negative impact on the vaccination coverage, and there were no significant differences in coverage in districts with CTC or in districts without CTC [8]. The CTC approach was also used in selected districts in Benin, Democratic Republic of the Congo, Côte d’Ivoire, Mauritania, and South Sudan.…”

How the use of vaccines outside the cold chain or in controlled temperature chain contributes to improving immunization coverage in low- and middle-income countries (LMICs): A scoping review of the literature

“…Two studies looked at the increased immunization coverage and other benefits of ‘off-label’ use of vaccines (Hepatitis B) outside the cold chain [ 22 , 23 ]. So far MenAfriVac vaccine, the first to be licensed by the WHO for use in ambient temperatures subject to meeting certain conditions – controlled temperature chain; has been extensively studied [ 19 , 20 , 24 ]. The study characteristics are summarized in Table 1 , and the key findings and limitations are summarized in Table 2 .…”

“…Six of the articles in this review studied and reported on the (potential) benefits or otherwise of keeping vaccines under CTC conditions [ 18 - 21 , 24 , 26 ]. Two of the studies were non-randomized trials with one that explored the economic evaluation of the controlled temperature chain approach for vaccine logistics during the meningitis A vaccine campaign in Togo using CTC vaccines, while the other was a field-based evaluation of adverse events following immunization (AEFI) from the same MenAfriVac (CTC) mass campaign conducted in Benin republic [ 20 , 26 ]; two articles were cross-sectional studies with one being an immunization coverage survey that assessed the impact of the vaccine administered CTC in Togo in 2014, and the second study examined the benefits of delivering Meningitis A (MenAfriVac) vaccines in a controlled temperature chain in the Benin Republic following a mass immunization campaign [ 21 , 24 ]; and one study used cross-sectional study data to model the economic benefits of MenAfriVac vaccine stored CTC in three regions of Chad republic where over 1.8 million eligible were vaccinated in December 2011 [ 19 ].…”

“…The majority of these studies assessed the effect of using vaccines stored OCC or CTC and showed increased vaccination coverage with the use of these strategies. Out of the 9000 eligible persons aged 1-29 years who were surveyed by Landoh et al [ 24 ], a very high immunization coverage was observed with about 98% of persons reporting being vaccinated. While the survey was conducted on a non-representative sample of the population, no statistically significant difference in vaccination coverage between CTC and non-CTC areas was observed (adjusted Odds Ratio AOR = 0.09; 95% confidence interval CI = [-0.27-0.45]).…”

“…From the field-based evaluation of adverse events following immunization (AEFI) conducted by Steffen et al [ 20 ] for the MenAfriVac mass campaign in Benin republic, there was no statistically significant difference in the incidence rates of AEFIs among the CTC and the non-CTC population. Landoh et al [ 24 ] in their cross-sectional study conducted in four of the ten regions that implemented CTC in Togo in 2014, reported a 2.3% incidence of mild to moderate AEFIs among study participants which included fever, abscesses, and swelling at the injection site. Coldiron and colleagues [ 27 ] having conducted a study randomizing of 4092 children to receive either RotaSIIL or placebo at 6, 10 and 14 weeks of age, with 2 years follow up, recorded only one case of intussusception 542 days after the third dose of RotaSIIL; a total of 107 deaths occurred split near half among the two groups, Serious Adverse Events (SAEs) occurred in 814 participants; 395 (19.3%) who had received RotaSIIL and 419 (20.5%) in the control group.…”