Population Impact and Effectiveness of Monovalent Rotavirus Vaccination in Urban Malawian Children 3 Years After Vaccine Introduction: Ecological and Case-Control Analyses

Bar-Zeev, Naor; Jere, Khuzwayo C.; Bennett, Aisleen; Pollock, Louisa; Tate, Jacqueline E.; Nakagomi, Osamu; Iturriza‐Gómara, Miren; Costello, Anthony; Mwansambo, Charles; Parashar, Umesh D.; Heyderman, Robert S.; French, Neil; Cunliffe, Nigel A.

doi:10.1093/cid/civ1183

Cited by 107 publications

(112 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These declines were particularly sharp in children 0–11 months and 12–23 months of age who were age-eligible for vaccination. These results are similar to those reported by other countries, including recent data from other African countries [8–13]. …”

Section: Discussionsupporting

confidence: 92%

Reduction in Diarrhea- and Rotavirus-related Healthcare Visits Among Children <5 Years of Age After National Rotavirus Vaccine Introduction in Zimbabwe

Mujuru

Yen

Nathoo

et al. 2017

Pediatric Infectious Disease Journal

Self Cite

View full text Add to dashboard Cite

Background: In Zimbabwe, rotavirus accounted for 41%–56% of acute diarrhea hospitalizations before rotavirus vaccine introduction in 2014. We evaluated rotavirus vaccination impact on acute diarrhea- and rotavirus-related healthcare visits in children. Methods: We examined monthly and annual acute diarrhea and rotavirus test-positive hospitalizations and Accident and Emergency Department visits among children <60 months of age at 3 active surveillance hospitals during 2012–2016; we compared prevaccine introduction (2012–2013) with postvaccine introduction (2015 and 2016) data for 2 of the hospitals. We examined monthly acute diarrhea hospitalizations by year and age group for 2013–2016 from surveillance hospital registers and monthly acute diarrhea outpatient visits reported to the Ministry of Health and Child Care during 2012–2016. Results: Active surveillance data showed winter seasonal peaks in diarrhea- and rotavirus-related visits among children <60 months of age during 2012–2014 that were substantially blunted in 2015 and 2016 after vaccine introduction; the percentage of rotavirus test-positive visits followed a similar seasonal pattern and decrease. Hospital register data showed similar pre-introduction seasonal variation and post-introduction declines in diarrhea hospitalizations among children 0–11 and 12–23 months of age. Monthly variation in outpatient diarrhea-related visits mirrored active surveillance data patterns. At 2 surveillance hospitals, the percentage of rotavirus-positive visits declined by 40% and 43% among children 0–11 months of age and by 21% and 33% among children 12–23 months of age in 2015 and 2016, respectively. Conclusion: Initial reductions in diarrheal illness among children <60 months of age, particularly among those 0–11 months of age, after vaccine introduction are encouraging. These early results provide evidence to support continued rotavirus vaccination and rotavirus surveillance in Zimbabwe.

show abstract

Section: Discussionsupporting

confidence: 92%

Reduction in Diarrhea- and Rotavirus-related Healthcare Visits Among Children <5 Years of Age After National Rotavirus Vaccine Introduction in Zimbabwe

Mujuru

Yen

Nathoo

et al. 2017

Pediatric Infectious Disease Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…Oral rotavirus vaccines confer homotypic and heterotypic protection against a wide variety of rotavirus genotypes [179,180]. However, as demonstrated in a range of settings, this protection appears to be lower against fully heterotypic strains (i.e., differing from the vaccine at both G and P epitopes) [181,182]. Such exposures may be more frequent in low-income countries, where the circulation of unusual rotavirus strains is more common [183,184].…”

Section: Post-vaccination Exposurementioning

confidence: 99%

“…[65], [98], [108], [135], [171], [196] [67], [133][134][135], [198][199][200][201] [8], [181], [182], [201], [203], [204] [28], [92], [93], [128], [131], [137], [138], [140], [130], [131], [157], [202] [ [43][44][45], [49], [61][62][63][64][65][66][67][68][69][70], [197] [ [155][156][157] [28], [98], [170][171][172]…”

Section: Conclusion and Future Perspectiveunclassified

Causes of Impaired Oral Vaccine Efficacy in Developing Countries

et al. 2017

View full text Add to dashboard Cite

Oral vaccines are less immunogenic when given to infants in low-income compared with high-income countries, limiting their potential public health impact. Here, we review factors that might contribute to this phenomenon, including transplacental antibodies, breastfeeding, histo blood group antigens, enteric pathogens, malnutrition, microbiota dysbiosis and environmental enteropathy. We highlight several clear risk factors for vaccine failure, such as the inhibitory effect of enteroviruses on oral poliovirus vaccine. We also highlight the ambiguous and at times contradictory nature of the available evidence, which undoubtedly reflects the complex and interconnected nature of the factors involved. Mechanisms responsible for diminished immunogenicity may be specific to each oral vaccine. Interventions aiming to improve vaccine performance may need to reflect the diversity of these mechanisms. Enteric pathogens are a substantial threat to public health. This threat takes many forms, from the toxin-producing bacteria (e.g., Vibrio cholerae) and flagellated protozoa (e.g., Giardia lamblia) that colonize the mucosal surface of the small intestine to the enteroviruses that are capable of spreading via the bloodstream to the CNS, causing acute flaccid paralysis (e.g., poliovirus). Each year, enteric pathogens cause hundreds of millions of cases of diarrhea and approximately 800,000 deaths, the vast majority of which occur among children in low-income countries [1]. The most common causes of childhood diarrheal morbidity include rotavirus, Cryptosporidium, enterotoxigenic Escherichia coli and Shigella [2].Vaccines against enteric pathogens are important tools for mitigating this disease burden. Oral vaccines offer several distinct benefits compared with parenteral vaccines. They can be produced in large quantities at relatively low cost, are easy to administer and have the capacity to induce local immunity in the intestinal mucosa, thereby protecting vaccinated individuals against subsequent infection and -by blocking onward transmission -enhancing herd immunity [3,4]. Currently licensed oral vaccines include live-attenuated poliovirus vaccines containing one, two or three serotypes, live-attenuated rotavirus vaccines (Rotarix R , RotaTeq R , Lanzhou lamb rotavirus vaccine [China only] and Rotavac R [India only]), live-attenuated cholera vaccine (CVD 103-HgR or Vaxchora TM ), inactivated cholera vaccines (Dukoral R and Shanchol R ) and live-attenuated typhoid vaccine (Ty21a). Other oral vaccines are in development, including those against Shigella, enterotoxigenic E. coli, Campylobacter and Clostridium difficile, as well as several novel rotavirus vaccine candidates (including the human neonatal vaccine RV3-BB [5] and an oral bovine pentavalent vaccine [6]).Yet oral vaccines have an Achilles' heel -their immunogenicity and efficacy is impaired in low-income countries that experience the greatest burden of enteric disease (Box 1). For example, Rotarix has a 1-year protective efficacy against severe rotavirus-associated gas...

show abstract

“…However, there is consistent evidence from clinical trials that RV have lower efficacies in low-and middle-income countries (LMIC): vaccine efficacies are 80 to 90% in high-income countries (HIC) and 40 to 60% in LMIC (3)(4)(5)(6)(7)(8). Indeed, there is growing evidence from vaccine effectiveness studies emerging from the field that in real-life use, vaccine effectiveness is also consistently lower in LMIC (9)(10)(11)(12).…”

mentioning

confidence: 99%

Contribution of Maternal Immunity to Decreased Rotavirus Vaccine Performance in Low- and Middle-Income Countries

Mwila

Chilengi

Simuyandi

et al. 2017

Clin Vaccine Immunol

View full text Add to dashboard Cite

The role of maternal immunity, received by infants either transplacentally or orally from breast milk, in rotavirus vaccine (RV) performance is evaluated here. Breastfeeding withholding has no effect on vaccine responses, but higher levels of transplacental rotavirus-specific IgG antibody contribute to reduced vaccine seroconversion. The gaps in knowledge on the factors associated with low RV efficacy in low-and middle-income countries (LMIC) remain, and further research is needed to shed more light on these issues. KEYWORDS immunization, low-and middle-income countries, maternal, rotavirus D espite the progress seen with the global introduction of rotavirus vaccines (RV), diarrhea is still a leading cause of death in children under the age of 5 years, and a substantial proportion of disease cases are still attributable to rotavirus infection. The latest estimates show that approximately 215,000 children die each year from rotavirusassociated diarrhea, and approximately 56% of these deaths are in sub-Saharan Africa (1). The World Health Organization (WHO) recommended the introduction of oral RV into national immunization programs (2), and many countries have heeded this call. As of September 2016, the WHO lists 86 countries as having included RV in their national immunization programs, and 6 more are in the course of doing so in 2016 (www.who.int/immunization/monitoring_surveillance/VaccineIntroStatus.pptx). Approximately 50% of the countries in Africa and Asia, over 80% of those in North America, South America, and Australia, and approximately 40% of those in Europe have introduced RV. Following RV introduction, there was a notable reduction in the number of deaths due to diarrhea (1). However, there is consistent evidence from clinical trials that RV have lower efficacies in low-and middle-income countries (LMIC): vaccine efficacies are 80 to 90% in high-income countries (HIC) and 40 to 60% in LMIC (3-8). Indeed, there is growing evidence from vaccine effectiveness studies emerging from the field that in real-life use, vaccine effectiveness is also consistently lower in LMIC (9-12).In addition to the differences in observed vaccine efficacy and effectiveness, there are also marked differences in vaccine-elicited immunity as reported by various vaccine-elicited antibody titers following rotavirus immunization (13)(14)(15)(16)(17)(18). A number of hypotheses have been put forward to explain the differences in efficacy and vaccineelicited immunity between HIC and LMIC. The hypotheses include (i) maternal factors (such as interference from transplacental antibodies and antibody and nonantibody breast milk components [13,[19][20][21][22][23] [38,39]). A better understanding of these factors which decrease the efficacy of RV in LMIC may help to inform interventions to improve efficacy and to further reduce the number of child deaths due to rotavirus disease. This review examines the correlations between maternal immune factors and RV responses and their potential effect on vaccine efficacy. NATURAL ROTAVIRUS...

show abstract

Population Impact and Effectiveness of Monovalent Rotavirus Vaccination in Urban Malawian Children 3 Years After Vaccine Introduction: Ecological and Case-Control Analyses

Cited by 107 publications

References 36 publications

Reduction in Diarrhea- and Rotavirus-related Healthcare Visits Among Children <5 Years of Age After National Rotavirus Vaccine Introduction in Zimbabwe

Reduction in Diarrhea- and Rotavirus-related Healthcare Visits Among Children <5 Years of Age After National Rotavirus Vaccine Introduction in Zimbabwe

Causes of Impaired Oral Vaccine Efficacy in Developing Countries

Contribution of Maternal Immunity to Decreased Rotavirus Vaccine Performance in Low- and Middle-Income Countries

Contact Info

Product

Resources

About