Serum vibriocidal responses when second doses of oral cholera vaccine are delayed 6 months in Zambia

Mwaba, John; Chisenga, Caroline Cleopatra; Xiao, Shaoming; Ng′ombe, Harriet; Banda, Elena; Shea, Patrick; Mabula-Bwalya, Chileshe M.; Mwila-Kazimbaya, Katayi; Laban, Natasha Makabilo; Alabi, Peter; Chirwa, Masuzyo; Simuyandi, Michelo; Harris, Jason B.; Iyer, Anita; Bosomprah, Samuel; Scalzo, Paul; Murt, Kelsey N.; Ram, Malathi; Kwenda, Geoffrey; Ali, Mohammad; Sack, David A.; Chilengi, Roma; Debes, Amanda K.

doi:10.1016/j.vaccine.2021.06.034

Cited by 10 publications

(11 citation statements)

References 31 publications

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“…Seroconversion was defined as a 4-fold or greater increase from the baseline vibriocidal titres [ 13 ]. A standard monoclonal antibody (mAb) and a high titres standard serum [ 14 ] were used to normalise the results in case of inter-assay variations.…”

Section: Methodsmentioning

confidence: 99%

Immunogenicity and waning immunity from the oral cholera vaccine (Shanchol™) in adults residing in Lukanga Swamps of Zambia

et al. 2022

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Introduction 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™ in Lukanga Swamps. Methods 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. Results 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 <80 and high ≥80) for both Inaba (p = 0.02) and Ogawa (p<0.0001). From a baseline of 13.58, anti-Ogawa GMT increased to 21.95 after the first dose, but rapidly waned to 14.52, 13.13, and 12.78 at months 6, 12 and 24 respectively, and then increased to 13.21, 18.67 and 23.65 at months 30, 36 and 48 respectively. A similar trend was observed for anti-Inaba GMT across the same time points. Conclusion We found that Shanchol™ was immunogenic in our study population and that vibriocidal antibodies may not be a good marker for long-term immunity. The observed rise in titres after 36 months suggests natural exposure, and this may be a critical time window opening for natural transmission in an endemic areas. We recommend re-vaccination at this time point in high risk areas.

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Section: Methodsmentioning

confidence: 99%

Immunogenicity and waning immunity from the oral cholera vaccine (Shanchol™) in adults residing in Lukanga Swamps of Zambia

et al. 2022

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“…14 A dose-interval study with similar design conducted in rural Zambia showed that extending the interval between doses to 6 months stimulated GMT vibriocidal titers that were not inferior to that stimulated by the 2-week schedule. 17 The study also found that some subgroups demonstrated a higher rise in Ogawa GMTs, but overall, the rise in GMTs were similar. Thus, both the Zambian and the Cameroon studies show noninferiority for an extended dose interval.…”

Section: Discussionmentioning

confidence: 72%

“…The serum vibriocidal responses were measured as previously described, 17,21 except that V. cholerae strains used as the target vibrio strains were originally isolated in Cameroon (Inaba FO14-2018-EN and Ogawa CPC-BACT-01). Briefly, the strains were incubated with serially diluted, heatinactivated serum and exogenous guinea pig complement DELAYED SECOND DOSE OF ORAL CHOLERA VACCINE (Sigma Aldrich, catalogue # S234395) on a shaker (50 rev/min) at 37 C for 1 hour.…”

Section: Ethical Considerationsmentioning

confidence: 99%

“… 13 There is also evidence that giving a booster dose after a prolonged period can lead to an augmented response, 16 suggesting there could be a benefit in delaying the second dose. A study in Zambia found that a second dose given at 6 months is not inferior, 17 but the results from the Zambia study were not known when planning the Cameroon study. It was also felt that additional data, including a group receiving the vaccine after an even longer interval, was needed to guide policy decisions regarding acceptable dose intervals.…”

Section: Introductionmentioning

confidence: 99%

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An Age-stratified, Randomized Immunogenicity Trial of Killed Oral Cholera Vaccine with Delayed Second Dose in Cameroon

Ateudjieu

Sack

Nafack³

et al. 2022

The American Journal of Tropical Medicine and Hygiene

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ABSTRACT. The recommended schedule for killed oral cholera vaccine (OCV) is two doses, 2 weeks apart. However, during vaccine campaigns, the second round is often delayed by several months. Because more information is needed to document antibody responses when the second dose is delayed, we conducted an open-label, phase 2, noninferiority clinical trial of OCV. One hundred eighty-six participants were randomized into three dose-interval groups (DIGs) to receive the second dose 2 weeks, 6 months, or 11.5 months after the first dose. The DIGs were stratified into three age strata: 1 to 4, 5 to 14, and > 14 years. Inaba and Ogawa vibriocidal titers were assessed before and after vaccination. The primary analysis was geometric mean titer (GMT) 2 weeks after the second dose. Data for primary analysis was available from 147 participants (54, 44, and 49 participants from the three DIGs respectively). Relative to the 2-week interval, groups receiving a delayed second dose had significantly higher GMTs after the second dose. Two weeks after the second dose, Inaba GMTs were 55.1 190.3, and 289.8 and Ogawa GMTs were 70.4, 134.5, and 302.4 for the three DIGs respectively. The elevated titers were brief, returning to lower levels within 3 months. We conclude that when the second dose of killed oral cholera vaccine was given after 6 or 11.5 months, vibriocidal titers were higher than when given after the standard period of 2 weeks. This provides reassurance that a delayed second dose does not compromise, but rather enhances, the serological response to the vaccine.

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“…Aside from the trial in Bangladesh, all estimates were based on secondary analyses that the studies were not powered to estimate. The Bangladesh trial is the only study to date that provides an age-stratified estimate of single-dose protection, and while it found an overall protective efficacy of 62% (95% CI: 43-75) during the 2-year follow up for individuals aged five years or older, it found no significant protection conferred by the Shanchol kOCV (a bioequivalent of Euvichol-Plus ® ) for individuals under five years of age (protective efficacy: -44%, 95% CI -220 to 35). Four of the seven observational studies provide single-dose vaccine effectiveness (VE) estimates only during the first 12 months post-vaccination with estimates ranging from 43% (95% CI -84-82) in Guinea to 93% (95% CI 69-98) in Haiti.…”

Section: Research In Contextmentioning

confidence: 91%

Effectiveness of one dose of killed oral cholera vaccine in an endemic community in the Democratic Republic of the Congo: A matched case-control study

Malembaka,

Bugeme,

Hutchins

et al. 2023

Preprint

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BackgroundA global shortage of cholera vaccines has increased use of single-dose regimens, rather than the standard two-dose regimen. There is limited evidence on single-dose protection, particularly in children. In late 2020 a mass vaccination campaign was conducted in Uvira, a cholera endemic urban setting in eastern Democratic Republic of the Congo. Coverage surveys showed that the majority of vaccinated people received only one dose. We examined the effectiveness of a single-dose of the oral cholera vaccine Euvichol-plus in this high-burden setting.MethodsIn this case-control study, we recruited medically-attended confirmed cholera cases and age-, sex-, and neighborhood-matched community controls during two distinct periods after mass vaccination, October 2021 to March 2022 (12-17 months post-vaccination) and October 2022 to May 2023 (24-31 months post-vaccination). The odds of vaccination in cases and controls were contrasted in conditional logistic regression models to estimate unadjusted and adjusted vaccine effectiveness.FindingsWe enrolled 432 confirmed cases and 1554 matched controls during the two study periods with 21.5% of cases being under five years old. The adjusted single-dose VE was 52% (95% CI: 32·3–66) 12-17 months post-vaccination and 40·8% (95% CI: 8·6–61·7) 24-31 months post-vaccination. Combining the two study periods led to an adjusted single-dose VE of 45% (95% CI 28·2–57·8), with no significant differences among children under five years old and older individuals.InterpretationA single-dose of Euvichol-Plus provided substantial protection against medically-attended cholera for at least 31 months post-vaccination in this cholera endemic setting.FundingThis work was supported by the Wellcome Trust and Gavi (GAVI-RFP-2019-062).

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Serum vibriocidal responses when second doses of oral cholera vaccine are delayed 6 months in Zambia

Cited by 10 publications

References 31 publications

Immunogenicity and waning immunity from the oral cholera vaccine (Shanchol™) in adults residing in Lukanga Swamps of Zambia

Immunogenicity and waning immunity from the oral cholera vaccine (Shanchol™) in adults residing in Lukanga Swamps of Zambia

An Age-stratified, Randomized Immunogenicity Trial of Killed Oral Cholera Vaccine with Delayed Second Dose in Cameroon

Effectiveness of one dose of killed oral cholera vaccine in an endemic community in the Democratic Republic of the Congo: A matched case-control study

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