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Understanding reduced rotavirus vaccine efficacy in low socio-economic settings.

Lopman BA, Pitzer VE, Sarkar R, Gladstone B, Patel M, Glasser J, Gambhir M, Atchison C, Grenfell BT, Edmunds WJ, Kang G, Parashar UD - PLoS ONE (2012)

Bottom Line: We then examined factors affecting efficacy.Also predicted was that vaccines are most effective against severe disease and efficacy declines with age in low but not high SES.The continued risk of severe disease in non-primary natural infections in low SES is a key factor underpinning reduced efficacy of rotavirus vaccines.

View Article: PubMed Central - PubMed

Affiliation: National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.

ABSTRACT

Introduction: Rotavirus vaccine efficacy ranges from >90% in high socio-economic settings (SES) to 50% in low SES. With the imminent introduction of rotavirus vaccine in low SES countries, understanding reasons for reduced efficacy in these settings could identify strategies to improve vaccine performance.

Methods: We developed a mathematical model to predict rotavirus vaccine efficacy in high, middle and low SES based on data specific for each setting on incidence, protection conferred by natural infection and immune response to vaccination. We then examined factors affecting efficacy.

Results: Vaccination was predicted to prevent 93%, 86% and 51% of severe rotavirus gastroenteritis in high, middle and low SES, respectively. Also predicted was that vaccines are most effective against severe disease and efficacy declines with age in low but not high SES. Reduced immunogenicity of vaccination and reduced protection conferred by natural infection are the main factors that compromise efficacy in low SES.

Discussion: The continued risk of severe disease in non-primary natural infections in low SES is a key factor underpinning reduced efficacy of rotavirus vaccines. Predicted efficacy was remarkably consistent with observed clinical trial results from different SES, validating the model. The phenomenon of reduced vaccine efficacy can be predicted by intrinsic immunological and epidemiological factors of low SES populations. Modifying aspects of the vaccine (e.g. improving immunogenicity in low SES) and vaccination program (e.g. additional doses) may bring improvements.

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Related in: MedlinePlus

Predicted vaccine efficacy on severe rotavirus gastroenteritis incidence in 6 to 23 month-olds.Step-wise influence of improving the underlying natural history of protection, immunogenicity of vaccines, and baseline disease incidence. The gray shaded area on the baseline bar indicates the potential incremental increase in VE from a third dose given at 6 months of age.
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pone-0041720-g002: Predicted vaccine efficacy on severe rotavirus gastroenteritis incidence in 6 to 23 month-olds.Step-wise influence of improving the underlying natural history of protection, immunogenicity of vaccines, and baseline disease incidence. The gray shaded area on the baseline bar indicates the potential incremental increase in VE from a third dose given at 6 months of age.

Mentions: Starting from a baseline of 51% efficacy among 6 to 23 month-olds in low SES, efficacy was projected to improve to 58% and 65%, respectively, if immunogenicity of vaccination was increased to levels from middle and high income countries (Figure 2 and Figure S3). The rest of the gap in efficacy (to 93% in high income settings) was a result of differences in the protection conferred by natural infection. Underlying incidence had no long-term impact on vaccine efficacy. A third dose of vaccine given at 6 months of age was predicted to increase efficacy from 51 to 60%.


Understanding reduced rotavirus vaccine efficacy in low socio-economic settings.

Lopman BA, Pitzer VE, Sarkar R, Gladstone B, Patel M, Glasser J, Gambhir M, Atchison C, Grenfell BT, Edmunds WJ, Kang G, Parashar UD - PLoS ONE (2012)

Predicted vaccine efficacy on severe rotavirus gastroenteritis incidence in 6 to 23 month-olds.Step-wise influence of improving the underlying natural history of protection, immunogenicity of vaccines, and baseline disease incidence. The gray shaded area on the baseline bar indicates the potential incremental increase in VE from a third dose given at 6 months of age.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3412858&req=5

pone-0041720-g002: Predicted vaccine efficacy on severe rotavirus gastroenteritis incidence in 6 to 23 month-olds.Step-wise influence of improving the underlying natural history of protection, immunogenicity of vaccines, and baseline disease incidence. The gray shaded area on the baseline bar indicates the potential incremental increase in VE from a third dose given at 6 months of age.
Mentions: Starting from a baseline of 51% efficacy among 6 to 23 month-olds in low SES, efficacy was projected to improve to 58% and 65%, respectively, if immunogenicity of vaccination was increased to levels from middle and high income countries (Figure 2 and Figure S3). The rest of the gap in efficacy (to 93% in high income settings) was a result of differences in the protection conferred by natural infection. Underlying incidence had no long-term impact on vaccine efficacy. A third dose of vaccine given at 6 months of age was predicted to increase efficacy from 51 to 60%.

Bottom Line: We then examined factors affecting efficacy.Also predicted was that vaccines are most effective against severe disease and efficacy declines with age in low but not high SES.The continued risk of severe disease in non-primary natural infections in low SES is a key factor underpinning reduced efficacy of rotavirus vaccines.

View Article: PubMed Central - PubMed

Affiliation: National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.

ABSTRACT

Introduction: Rotavirus vaccine efficacy ranges from >90% in high socio-economic settings (SES) to 50% in low SES. With the imminent introduction of rotavirus vaccine in low SES countries, understanding reasons for reduced efficacy in these settings could identify strategies to improve vaccine performance.

Methods: We developed a mathematical model to predict rotavirus vaccine efficacy in high, middle and low SES based on data specific for each setting on incidence, protection conferred by natural infection and immune response to vaccination. We then examined factors affecting efficacy.

Results: Vaccination was predicted to prevent 93%, 86% and 51% of severe rotavirus gastroenteritis in high, middle and low SES, respectively. Also predicted was that vaccines are most effective against severe disease and efficacy declines with age in low but not high SES. Reduced immunogenicity of vaccination and reduced protection conferred by natural infection are the main factors that compromise efficacy in low SES.

Discussion: The continued risk of severe disease in non-primary natural infections in low SES is a key factor underpinning reduced efficacy of rotavirus vaccines. Predicted efficacy was remarkably consistent with observed clinical trial results from different SES, validating the model. The phenomenon of reduced vaccine efficacy can be predicted by intrinsic immunological and epidemiological factors of low SES populations. Modifying aspects of the vaccine (e.g. improving immunogenicity in low SES) and vaccination program (e.g. additional doses) may bring improvements.

Show MeSH
Related in: MedlinePlus