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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

Relationship between vaccine efficacy against severe RV-GE and the proportion of infections that are primary or secondary, by age group.In high (black points) and middle (green points) SES VE remains stable across age groups, despite the fact that the proportions of infections decrease with age, because in these settings all severe disease is confined to the first two infections. In low SES, VE falls as the proportion of infections that are primary or secondary decreases because severe disease continues to occur in subsequent infections.
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pone-0041720-g003: Relationship between vaccine efficacy against severe RV-GE and the proportion of infections that are primary or secondary, by age group.In high (black points) and middle (green points) SES VE remains stable across age groups, despite the fact that the proportions of infections decrease with age, because in these settings all severe disease is confined to the first two infections. In low SES, VE falls as the proportion of infections that are primary or secondary decreases because severe disease continues to occur in subsequent infections.

Mentions: Figure 3 illustrates the relationship between age-specific vaccine efficacy estimates and the proportion of infections that were either primary or secondary (as projected by the model). In high and middle SES, VE remained steady as the proportion of infections that were primary or secondary decreased with age. In low SES, VE fell with this proportion.


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)

Relationship between vaccine efficacy against severe RV-GE and the proportion of infections that are primary or secondary, by age group.In high (black points) and middle (green points) SES VE remains stable across age groups, despite the fact that the proportions of infections decrease with age, because in these settings all severe disease is confined to the first two infections. In low SES, VE falls as the proportion of infections that are primary or secondary decreases because severe disease continues to occur in subsequent infections.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0041720-g003: Relationship between vaccine efficacy against severe RV-GE and the proportion of infections that are primary or secondary, by age group.In high (black points) and middle (green points) SES VE remains stable across age groups, despite the fact that the proportions of infections decrease with age, because in these settings all severe disease is confined to the first two infections. In low SES, VE falls as the proportion of infections that are primary or secondary decreases because severe disease continues to occur in subsequent infections.
Mentions: Figure 3 illustrates the relationship between age-specific vaccine efficacy estimates and the proportion of infections that were either primary or secondary (as projected by the model). In high and middle SES, VE remained steady as the proportion of infections that were primary or secondary decreased with age. In low SES, VE fell with this proportion.

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