Rotavirus Genotypes over Time in Vaccine-Introducing and Non-Introducing Countries Open Access
Liu, Zihao (Spring 2022)
Abstract
Background
Rotavirus vaccines have substantially lowered the global rotavirus gastroenteritis burden in children aged <5 years. However, vaccines may offer less protection against some rotavirus genotypes, including G2P[4], and vaccine introduction may also exert vaccine-induced selective pressures on circulating rotavirus strains.
Methods
To examine if strains that vaccines may be less effective against became more dominant over time, we systematically reviewed literature of rotavirus surveillance reporting genotype distributions between 2002 and 2019. We included data from countries with at least 6 years of surveillance data and, if a rotavirus vaccine was introduced into their national immunization program during the time period identified in the data (between 2002 to 2019, specific surveillance period varied by country), at least 2 years of data pre- and post-introduction. We estimated odds of infection by a particular rotavirus genotype in response to G1P[8] strain in different scenario by fitting two multinomial logistic regression. One having vaccine introduction status as main exposure and another having surveillance year as exposure. The final dataset included five vaccine-introducing countries (Ethiopia, Kenya, Italy, South Africa, and Zimbabwe) and five non-introducing countries (Argentina, China, Myanmar, Nepal, and Ukraine).
Results
257 records were used in the analysis, with 83,017 overall positive rotavirus cases included. For vaccine-introducing countries, the odds of infection with G2P[4] increased each year in South Africa [adjusted odds ratio (aOR): 2.47, 95% confidence interval (CI): 2.47-2.48] and Kenya (aOR: 4.24, 95% CI: 4.24-4.25). For non-introducing countries, the odds of infection with G2P[4] increased each year in China (aOR=1.46, 95% CI 1.46-1.48) and Ukraine (aOR=1.93, 95% CI 1.93-1.95). G2P[4] infection odds increased over time in some introducing and non-introducing countries; however, introducing countries had much higher odds of G2P[4] infection as time went on than non-introducing countries.
Conclusion
Both the descriptive analysis and regression analysis indicate an overall decrease of G1P[8] strain and an increase of G2P[4] over time for most countries from both introducing and non-introducing groups. These findings highlight the need for continued surveillance in both vaccine-introducing and non-introducing countries to monitor circulating rotavirus genotypes and assess potential impacts of vaccine introduction.
Table of Contents
TABLE OF CONTENTS
DISTRIBUTION AGREEMENT......................................................................................................................................I
APPROVAL SHEET.....................................................................................................................................................II
ABSTRACT COVER SHEET.........................................................................................................................................III
ABSTRACT...............................................................................................................................................................IV
THESIS COVER PAGE.................................................................................................................................................V
ACKNOWLEDGEMENTS...........................................................................................................................................VI
TABLE OF CONTENTS.............................................................................................................................................VII
INTRODUCTION.....................................................................................................................................................1
Background..........................................................................................................................................................1
Objective..............................................................................................................................................................2
METHOD................................................................................................................................................................3
Search Strategy and Selection Criteria......................................................................................................................4
Data Analysis .........................................................................................................................................................5
Descriptive Analysis................................................................................................................................................5
Genotype Analysis.................................................................................................................................................. 5
Statistical Analysis..................................................................................................................................................5
RESULT.................................................................................................................................................................. 6
Rotavirus Strain Prevalence and Diversity: Vaccine Introduction Countries............................................................ .....7
Rotavirus Strain Prevalence and Diversity: Vaccine Non-Introducing Countries...........................................................9
Genotype Diversity Index and Vaccination Introduction Status...................................................................................9
Multinomial Logistic Regression.............................................................................................................................10
DISCUSSION..........................................................................................................................................................11
TABLES & FIGURES................................................................................................................................................16
Table 1..................................................................................................................................................................16
Table 2..................................................................................................................................................................17
Table 3..................................................................................................................................................................18
Table 4..................................................................................................................................................................19
Figure 1.................................................................................................................................................................20
Figure 2.................................................................................................................................................................21
Figure 3.................................................................................................................................................................22
Figure 4.................................................................................................................................................................23
Figure 5.................................................................................................................................................................24
REFERENCE...........................................................................................................................................................26
SUPPLEMENTARY MATERIAL.................................................................................................................................30
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