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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 age-specific efficacy on severe RV-GE and all RV-GE.A) Vaccine efficacy: Severe RV-GE. B) Vaccine efficacy: All RV-GE.
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pone-0041720-g001: Predicted age-specific efficacy on severe RV-GE and all RV-GE.A) Vaccine efficacy: Severe RV-GE. B) Vaccine efficacy: All RV-GE.

Mentions: In the 6 to 23 month age group, the model generated vaccine efficacy (VE) estimates against severe RV-GE of 93%, 86% and 51% in high, middle and low SES, respectively (Table 2). Under the higher birth rate scenario (25 per 1000 per year) in low SES, our estimate of VE was marginally reduced (by 2%). When considering the range of seroconversion values in the literature, we predicted VE to range from 79% to 99% in high SES, 77% to 93% in middle SES and 47% to 53% in low SES. Against all RV-GE, VE was 66%, 58% and 53%, respectively. VE decreased in low SES in 3 year olds and was negligible in 4 year olds. In contrast, VE did not decrease amongst older age groups in middle or high income settings (Figure 1).


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 age-specific efficacy on severe RV-GE and all RV-GE.A) Vaccine efficacy: Severe RV-GE. B) Vaccine efficacy: All RV-GE.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0041720-g001: Predicted age-specific efficacy on severe RV-GE and all RV-GE.A) Vaccine efficacy: Severe RV-GE. B) Vaccine efficacy: All RV-GE.
Mentions: In the 6 to 23 month age group, the model generated vaccine efficacy (VE) estimates against severe RV-GE of 93%, 86% and 51% in high, middle and low SES, respectively (Table 2). Under the higher birth rate scenario (25 per 1000 per year) in low SES, our estimate of VE was marginally reduced (by 2%). When considering the range of seroconversion values in the literature, we predicted VE to range from 79% to 99% in high SES, 77% to 93% in middle SES and 47% to 53% in low SES. Against all RV-GE, VE was 66%, 58% and 53%, respectively. VE decreased in low SES in 3 year olds and was negligible in 4 year olds. In contrast, VE did not decrease amongst older age groups in middle or high income settings (Figure 1).

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