Volume 35, Issue 38, Pages 5081-5224 (12 September 2017)
Oral cholera vaccine coverage in hard-to-reach fishermen communities after two mass Campaigns, Malawi, 2016
Original Research Article
Delphine Sauvageot, Christel Saussier, Abebe Gobeze, Sikhona Chipeta, Innocent Mhango, Gift Kawalazira, Martin A. Mengel, Dominique Legros, Philippe Cavailler, Maurice M’bang’ombe
From December 2015 to August 2016, a large epidemic of cholera affected the fishermen of Lake Chilwa in Malawi. A first reactive Oral Cholera Vaccines (OCV) campaign was organized, in February, in a 2 km radius of the lake followed by a preemptive one, conducted in November, in a 25 km radius. We present the vaccine coverage reached in hard-to-reach population using simplified delivery strategies.
We conducted two-stage random-sampling cross-sectional surveys among individuals living in a 2 km and 25 km radius of Lake Chilwa (islands and floating homes included). Individuals aged 12 months and older from Machinga and Zomba districts were sampled: 43 clusters of 14 households were surveyed. Simplified strategies were used for those living in islands and floating homes: self- delivery and community-supervised delivery of the second dose. Vaccine coverage (VC) for at-least-two-doses was estimated taking into account sampling weights and design effects.
A total of 1176 households were surveyed (2.7% of non-response). Among the 2833 individuals living in the 2 km radius of Lake and the 2915 in the 25 km radius: 457 (16.1%) and 239 (8.2%) lived in floating homes or on islands at some point in the year, respectively. For the overall population, VC was 75.6% and 54.2%, respectively. In the 2 km radius, VC was 92.2% for those living on the lake at some point of the year: 271 (64.8%) used the simplified strategies. The main reasons for non-vaccination were absence during the campaign and vaccine shortage. Few adverse events occurring in the 24 h following vaccination was reported.
We reached a high two-dose coverage of the most at-risk population using simplified delivery strategies. Because of the high fishermen mobility, regular catch-up campaigns or another strategy specifically targeting fishermen need to be assessed for more efficient vaccines use.