Immunogenicity and waning immunity from the oral cholera vaccine

• Published in: PloS one 2022-01, Vol.17 (1), p.e0262239
• Main Authors: Ng'ombe, Harriet, Simuyandi, Michelo, Mwaba, John, Luchen, Charlie Chaluma, Alabi, Peter, Chilyabanyama, Obvious Nchimunya, Mubanga, Cynthia, Hatyoka, Luiza Miyanda, Muchimba, Mutinta, Bosomprah, Samuel, Chilengi, Roma, Kwenda, Geoffrey, Chisenga, Caroline Cleopatra
• Format: Article
• Language: English
• Subjects: Cholera; Control; Health aspects; Immune response; Oral vaccines; Patient outcomes; Risk factors; Swamps
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0262239

In cholera endemic areas, the periodicity of cholera outbreaks remains unpredictable, making it difficult to organize preventive efforts. Lack of data on duration of protection conferred by oral cholera vaccines further makes it difficult to determine when to deploy preemptive vaccination. We report on the immunogenicity and waning of immunity to Shanchol.sup.[TM] in Lukanga Swamps. We enrolled a cohort of 223 participants aged between 18 and 65 years old from whom serum samples were collected at baseline, day 28 before administration of the second dose, and consecutively at 6, 12, 24, 30, 36, and 48 months. Vibriocidal antibody titres were measured and expressed as geometric mean titres. Box plots and 95% CI were computed at each visit for both Inaba and Ogawa. Seroconversion was defined as a four fold or greater increase in antibody titres compared to baseline titres. Overall, seroconversion against V. cholerae Inaba and Ogawa after 1st dose was 35/134 (26%) and 34/134 (25%) respectively. We observed a statistical difference in seroconversion between the two subgroups of baseline titres (low