Dataset Information

Prolonging herd immunity to cholera via vaccination: Accounting for human mobility and waning vaccine effects.

ABSTRACT:

Background

Oral cholera vaccination is an approach to preventing outbreaks in at-risk settings and controlling cholera in endemic settings. However, vaccine-derived herd immunity may be short-lived due to interactions between human mobility and imperfect or waning vaccine efficacy. As the supply and utilization of oral cholera vaccines grows, critical questions related to herd immunity are emerging, including: who should be targeted; when should revaccination be performed; and why have cholera outbreaks occurred in recently vaccinated populations?

Methods and findings

We use mathematical models to simulate routine and mass oral cholera vaccination in populations with varying degrees of migration, transmission intensity, and vaccine coverage. We show that migration and waning vaccine efficacy strongly influence the duration of herd immunity while birth and death rates have relatively minimal impacts. As compared to either periodic mass vaccination or routine vaccination alone, a community could be protected longer by a blended "Mass and Maintain" strategy. We show that vaccination may be best targeted at populations with intermediate degrees of mobility as compared to communities with very high or very low population turnover. Using a case study of an internally displaced person camp in South Sudan which underwent high-coverage mass vaccination in 2014 and 2015, we show that waning vaccine direct effects and high population turnover rendered the camp over 80% susceptible at the time of the cholera outbreak beginning in October 2016.

Conclusions

Oral cholera vaccines can be powerful tools for quickly protecting a population for a period of time that depends critically on vaccine coverage, vaccine efficacy over time, and the rate of population turnover through human mobility. Due to waning herd immunity, epidemics in vaccinated communities are possible but become less likely through complementary interventions or data-driven revaccination strategies.

SUBMITTER: Peak CM

PROVIDER: S-EPMC5847240 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Publications

Prolonging herd immunity to cholera via vaccination: Accounting for human mobility and waning vaccine effects.

Peak Corey M CM Reilly Amanda L AL Azman Andrew S AS Buckee Caroline O CO

PLoS neglected tropical diseases 20180228 2

<h4>Background</h4>Oral cholera vaccination is an approach to preventing outbreaks in at-risk settings and controlling cholera in endemic settings. However, vaccine-derived herd immunity may be short-lived due to interactions between human mobility and imperfect or waning vaccine efficacy. As the supply and utilization of oral cholera vaccines grows, critical questions related to herd immunity are emerging, including: who should be targeted; when should revaccination be performed; and why have c ...[more]

PMID: 29489815

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Project description:BackgroundHumoral responses to coronavirus disease 2019 (COVID-19) vaccines in hemodialysis (HD) patients can direct vaccination policy.MethodsWe compared 409 COVID-19-naïve HD patients from 13 HD units in Israel to 148 non-dialysis-dependent COVID-19-naïve controls. Twenty-four previously infected (antinucleocapsid positive) HD patients were analysed separately. Blood samples were obtained ≥14 days post-vaccination (BNT162b2, Pfizer/BioNTech) to assess seroconversion rates and titers of anti-spike (anti-S) and neutralizing antibodies.ResultsThe median time from vaccination to blood sample collection was 82 days [interquartile range (IAR) 64-87] and 89 days (IQR 68-96) for HD patients and controls, respectively. Seroconversion rates were lower in HD patients compared with controls for both anti-S and neutralizing antibodies (89% and 77% versus 99.3%, respectively; P < 0.0001). Antibody titers were also significantly lower in HD patients compared with controls {median 69.6 [IQR 33.2-120] versus 196.5 [IQR 118.5-246], P < 0.0001; geometric mean titer [GMT] 23.3 [95% confidence interval (CI) 18.7-29.1] versus 222.7 [95% CI 174-284], P < 0.0001, for anti-S and neutralizing antibodies, respectively}. Multivariate analysis demonstrated dialysis dependence to be strongly associated with lower antibody responses and antibody titers waning with time. Age, low serum albumin and low lymphocyte count were also associated with lower seroconversion rates and antibody titers. HD patients previously infected with sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had no difference in their seroconversion rates or antibody titers compared with COVID-19-naïve patients.ConclusionThis study demonstrates diminished and waning humoral responses following COVID-19 vaccination in a large and diverse cohort of HD patients, including those previously infected with SARS-CoV-2. Considering these results and reduced vaccine effectiveness against variants of concern, in addition to continued social distancing precautions, a third booster dose should be considered in this population.

Dataset Information

Prolonging herd immunity to cholera via vaccination: Accounting for human mobility and waning vaccine effects.

Background

Methods and findings

Conclusions

Publications

Prolonging herd immunity to cholera via vaccination: Accounting for human mobility and waning vaccine effects.

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