Sustained Reduction of Childhood Diarrhea-Related Mortality and Hospitalizations in Mexico After Rotavirus Vaccine Universalization

Rotavirus Vaccine Impact since Its Introduction in the National Immunization Program of Argentina

INTRODUCTION

Rotavirus (RV) is the most common cause of childhood diarrhea. Argentina introduced RV vaccination in the National Immunization Program in January 2015. This study evaluates the impact of RV vaccine implementation on the burden of acute diarrheal disease (ADD) and RV positive cases, and hospitalizations among children in Argentina.

METHODS

A counterfactual time-series analysis was performed. Data on ADD (2013-2018) and RV diarrhea (2012-2018) cases in children aged < 5 years were collected from the National Healthcare Surveillance System (clinical and laboratory data). Data on hospital discharges following ADD and RV diarrhea (2011-2017) were retrieved from the Health Statistics and Information Office. All data were classified by the age groups < 1 year, < 2 years, 2-5 years. Vaccine impact was defined as the difference between the predicted time trend (simulated using 2012-2014 data) and the actual post-vaccination data (2015-2018).

RESULTS

A significant reduction of 22.1% of notified ADD cases and 15.4% of hospital discharges following ADD among children < 2 years was observed in the 3 years after RV vaccine implementation. Data also showed a significant decline of 54.0% and 59.4% of notified RV cases in children < 2 and < 1 years, respectively, and a reduction of 39.3% and 40.8% in RV hospital discharges for the same age groups.

CONCLUSION

This study shows a significant reduction in notified ADD cases and RV cases and hospital discharges following ADD and RV cases in children < 2 years after RV vaccine introduction in Argentina in 2015.

Genetic diversity of species A rotaviruses detected in clinical and environmental samples, including porcine-like rotaviruses from hospitalized children in the Philippines

Rotaviruses are the major cause of severe acute diarrhea in infants and young children. Rotaviruses exhibit zoonosis and thereby infect both humans and animals. Viruses detected in urban rivers possibly reflect the presence of circulating viruses in the catchment. The present study investigates the genetic diversity of species A rotaviruses detected from river water and stool of hospitalized children with acute diarrhea in Tacloban City, the Philippines. Species A rotaviruses were detected by real-time RT-PCR and their genotypes were identified by multiplex PCR and sequencing of partial regions of VP7 and VP4. Rotaviruses were detected in 85.7% (30/35) of the river water samples and 62.7% (151/241) of the clinical samples. Genotypes of VP7 in the river water samples were G1, G2, G3, G4, G5, and G9, and those of VP4 were P[3], P[4], P[6], P[8], and P[13]. Genotypes of viruses from the clinical samples were G2P[4], G1P[8], G3P[8], G4P[6], G5P[6], and G9P[8]. Among those, G2P[4] in clinical samples (77.9%, 81/104) and P[4] of VP4 in river water samples (67.5%, 56/83)) were the most frequently detected rotavirus genotypes. However, G5 was the more frequently detected than G2 in the river water samples (42% vs. 13%) which may be originated from porcine rotavirus. Sequence analyses of eleven gene segments revealed one G5P[6] and two G4P[6] rotaviruses in the clinical samples, wherein, several gene segments were closely related to porcine rotaviruses. The constellation of these rotavirus genes suggests the emergence of reassortment between human and porcine rotavirus due to interspecies transmission. Although two commercial rotavirus vaccines are available now, these vaccines are designed to confer immunity against the major human rotaviruses. Constant monitoring of viral variety in populated areas where humans and domestic animals live in close proximity provides vital information related to the diversity of rotaviruses in a human population.

Group A rotavirus surveillance before vaccine introduction in Italy, September 2014 to August 2017

Introduction

Group A rotaviruses (RVA) are the leading cause of acute gastroenteritis (AGE) in young children, causing ca 250,000 deaths worldwide, mainly in low-income countries. Two proteins, VP7 (glycoprotein, G genotype) and VP4 (protease-sensitive protein, P genotype), are the basis for the binary RVA nomenclature. Although 36 G types and 51 P types are presently known, most RVA infections in humans worldwide are related to five G/P combinations: G1P[8], G2P[4], G3P[8], G4P[8], G9P[8].

Aim

This study aimed to characterise the RVA strains circulating in Italy in the pre-vaccination era, to define the trends of circulation of genotypes in the Italian paediatric population.

Methods

Between September 2014 and August 2017, after routine screening in hospital by commercial antigen detection kit, 2,202 rotavirus-positive samples were collected in Italy from children hospitalised with AGE; the viruses were genotyped following standard European protocols.

Results

This 3-year study revealed an overall predominance of the G12P[8] genotype (544 of 2,202 cases; 24.70%), followed by G9P[8] (535/2,202; 24.30%), G1P[8] (459/2,202; 20.84%) and G4P[8] (371/2,202; 16.85%). G2P[4] and G3P[8] genotypes were detected at low rates (3.32% and 3.09%, respectively). Mixed infections accounted for 6.49% of cases (143/2,202), uncommon RVA strains for 0.41% of cases (9/2,202).

Conclusions

The emergence of G12P[8] rotavirus in Italy, as in other countries, marks this genotype as the sixth most common human genotype. Continuous surveillance of RVA strains and monitoring of circulating genotypes are important for a better understanding of rotavirus evolution and genotype distribution, particularly regarding strains that may emerge from reassortment events.

The control of diarrhea, the case of a rotavirus vaccine

[No disponible]

Immunogenicity of four doses of oral poliovirus vaccine when co-administered with the human neonatal rotavirus vaccine (RV3-BB)

BACKGROUND

The RV3-BB human neonatal rotavirus vaccine was developed to provide protection from severe rotavirus disease from birth. The aim of this study was to investigate the potential for mutual interference in the immunogenicity of oral polio vaccine (OPV) and RV3-BB.

METHODS

A randomized, placebo-controlled trial involving 1649 participants was conducted from January 2013 to July 2016 in Central Java and Yogyakarta, Indonesia. Participants received three doses of oral RV3-BB, with the first dose given at 0-5 days (neonatal schedule) or ~8 weeks (infant schedule), or placebo. Two sub-studies assessed the immunogenicity of RV3-BB when co-administered with either trivalent OPV (OPV group, n = 282) or inactivated polio vaccine (IPV group, n = 333). Serum samples were tested for antibodies to poliovirus strains 1, 2 and 3 by neutralization assays following doses 1 and 4 of OPV.

RESULTS

Sero-protective rates to poliovirus type 1, 2 or 3 were similar (range 0.96-1.00) after four doses of OPV co-administered with RV3-BB compared with placebo. Serum IgA responses to RV3-BB were similar when co-administered with either OPV or IPV (difference in proportions OPV vs IPV: sIgA responses; neonatal schedule 0.01, 95% CI -0.12 to 0.14; p = 0.847; infant schedule -0.10, 95% CI -0.21 to -0.001; p = 0.046: sIgA GMT ratio: neonatal schedule 1.23, 95% CI 0.71-2.14, p = 0.463 or infant schedule 1.20, 95% CI 0.74-1.96, p = 0.448).

CONCLUSIONS

The co-administration of OPV with RV3-BB rotavirus vaccine in a birth dose strategy did not reduce the immunogenicity of either vaccine. These findings support the use of a neonatal RV3-BB vaccine where either OPV or IPV is used in the routine vaccination schedule.

Impact of Rotavirus Vaccine Introduction and Postintroduction Etiology of Diarrhea Requiring Hospital Admission in Haydom, Tanzania, a Rural African Setting

Background

No data are available on the etiology of diarrhea requiring hospitalization after rotavirus vaccine introduction in Africa. The monovalent rotavirus vaccine was introduced in Tanzania on 1 January 2013. We performed a vaccine impact and effectiveness study as well as a quantitative polymerase chain reaction (qPCR)–based etiology study at a rural Tanzanian hospital.

Methods

We obtained data on admissions among children <5 years to Haydom Lutheran Hospital between 1 January 2010 and 31 December 2015 and estimated the impact of vaccine introduction on all-cause diarrhea admissions. We then performed a vaccine effectiveness study using the test-negative design. Finally, we tested diarrheal specimens during 2015 by qPCR for a broad range of enteropathogens and calculated pathogen-specific attributable fractions (AFs).

Results

Vaccine introduction was associated with a 44.9% (95% confidence interval [CI], 17.6%–97.4%) reduction in diarrhea admissions in 2015, as well as delay of the rotavirus season. The effectiveness of 2 doses of vaccine was 74.8% (95% CI, –8.2% to 94.1%) using an enzyme immunoassay–based case definition and 85.1% (95% CI, 26.5%–97.0%) using a qPCR-based case definition. Among 146 children enrolled in 2015, rotavirus remained the leading etiology of diarrhea requiring hospitalization (AF, 25.8% [95% CI, 24.4%–26.7%]), followed by heat-stable enterotoxin-producing Escherichia coli (AF, 18.4% [95% CI, 12.9%–21.9%]), Shigella/enteroinvasive E. coli (AF, 14.5% [95% CI, 10.2%–22.8%]), and Cryptosporidium (AF, 7.9% [95% CI, 6.2%–9.3%]).

Conclusions

Despite the clear impact of vaccine introduction in this setting, rotavirus remained the leading etiology of diarrhea requiring hospitalization. Further efforts to maximize vaccine coverage and improve vaccine performance in these settings are warranted.

Global impact of rotavirus vaccine introduction on rotavirus hospitalisations among children under 5 years of age, 2008-16: findings from the Global Rotavirus Surveillance Network

BACKGROUND

Rotavirus vaccine use in national immunisation programmes has led to declines in hospital admissions for rotavirus gastroenteritis among children; however, the global impact of rotavirus vaccine introduction has not been described using primary data. We describe the impact of rotavirus vaccine introduction on admissions for acute rotavirus gastroenteritis in primarily low-income and middle-income countries, using 9 years of data from the WHO-coordinated Global Rotavirus Surveillance Network (GRSN).

METHODS

Between Jan 1, 2008, and Dec 31, 2016, children younger than 5 years of age who were admitted to hospital with acute gastroenteritis were prospectively enrolled in GRSN sites. We included sites that enrolled children and collected stool specimens monthly and tested at least 100 specimens annually in the impact analysis, with a separate analysis taking into account site continuity. We compared proportions of acute gastroenteritis cases positive for rotavirus in the pre-vaccine and post-vaccine periods and calculated mean proportion changes for WHO regions, with 95% CIs; these findings were then compared with interrupted time series analyses. We did further sensitivity analyses to account for rotavirus vaccination coverage levels and sites that collected specimens for at least 11 months per year and tested at least 80 specimens per year. We also analysed the age distribution of rotavirus-positive cases before and after vaccine introduction.

FINDINGS

403 140 children younger than 5 years of age admitted to hospital with acute gastroenteritis from 349 sites in 82 countries were enrolled over the study period, of whom 132 736 (32·9%) were positive for rotavirus. We included 305 789 children from 198 sites in 69 countries in the impact analysis. In countries that had not introduced rotavirus vaccine in their national immunisation programmes, rotavirus was detected in 38·0% (95% CI 4·8-73·4) of admissions for acute gastroenteritis annually whereas in those that have introduced the vaccine, rotavirus was detected in 23·0% (0·7-57·7) of admissions for acute gastroenteritis, showing a 39·6% (35·4-43·8) relative decline following introduction. Interrupted time series analyses confirmed these findings. Reductions by WHO regions ranged from 26·4% (15·0-37·8) in the Eastern Mediterranean Region to 55·2% (43·0-67·4) in the European Region and were sustained in nine countries (contributing up to 31 sites) for 6-10 years. The age distribution of children with rotavirus gastroenteritis shifted towards older children after rotavirus vaccine introduction.

INTERPRETATION

A significant and sustained reduction in the proportion of hospital admissions for acute gastroenteritis due to rotavirus was seen among children younger than 5 years in GRSN sites following rotavirus vaccine introduction. These findings highlight the need to incorporate rotavirus vaccines into immunisation programmes in countries that have not yet introduced them and underline the importance of high-quality surveillance.

FUNDING

The GRSN receives funding from Gavi, the Vaccine Alliance and the US Centers for Disease Control and Prevention. No specific funding was provided for this Article.

Evidence of reduction of rotavirus diarrheal disease after rotavirus vaccine introduction in national immunization programs in the African countries: Report of the 11th African rotavirus symposium held in Lilongwe, Malawi

The 11th African Rotavirus Symposium was held in Lilongwe, Malawi from May 28th to 30th 2017. Over 270 delegates (73% from Africa) from 40 countries of which 30 (75%) were from African countries attended the symposium. Participants in this symposium included research scientists, clinicians, immunization managers, public health officials, policymakers and vaccine manufacturers. At the time of the symposium, 38 of the 54 (70%) countries in Africa had introduced rotavirus vaccines into their national immunization schedules. Delegates shared progress from rotavirus surveillance and vaccine impact monitoring, demonstrating the impact of the vaccine against rotavirus diarrheal hospitalizations. Data supported the beneficial effect and safety of WHO pre-qualified available vaccines up to 2017 (RotaTeq, Rotarix). This symposium highlighted the dramatic impact of the rotavirus vaccination, called for urgent adoption of these vaccines in remaining countries, particularly those with high disease burden and large birth cohorts (e.g. Nigeria, Democratic Republic of Congo) to attain the full public health benefits of rotavirus vaccination in Africa.

Experiences with rotavirus vaccines: can we improve rotavirus vaccine impact in developing countries?

Rotavirus vaccines have been introduced into over 95 countries globally and demonstrate substantial impact in reducing diarrheal mortality and diarrheal hospitalizations in young children. The vaccines are also considered by WHO as "very cost effective" interventions for young children, particularly in countries with high diarrheal disease burden. Yet the full potential impact of rotavirus immunization is yet to be realized. Large countries with big birth cohorts and where disease burden is high in Africa and Asia have not yet implemented rotavirus vaccines at all or at scale. Significant advances have been made demonstrating the impact of the vaccines in low- and lower-middle income countries, yet the modest effectiveness of the vaccines in these settings is challenging. Current research highlights these challenges and considers alternative strategies to overcome them, including alternative immunization schedules and host factors that may inform us of new opportunities.

[Vaccination coverage and proportion of incomplete vaccination schedule in children under seven years of age in Mexico]

OBJECTIVE

To assess vaccination coverage in children under seven years of age.

MATERIALS AND METHODS

Study based on the Halfway National Health and Nutrition Survey (Ensanut MC 2016).

RESULTS

Full vaccination coverage in children <1 year was 51.7%, (range: 67.6% [pentavalent (PV)] to 93.9% [BCG]), in those aged 12-23 months was 53.9% (range: 68.5% [MMR] to 98.3% [BCG]) and in those 24-35 months was 63.2% (range: 85.3% [pneumococcal]) to 98.6% [BCG]). In children aged six years, the coverage of 1 MMR dose was 97.8% and 50.7% for two doses. Only 2.2% of six year olds were not vaccinated. Variables associated with incomplete schedule were age of 2-5 months, mother being under 20 years of age or maternal language indigenous.

CONCLUSIONS

The vaccination program needs to improve recruitment of newborns and their follow-up until they complete their immunization schedule, taking advantage of the local contacts with health services to vaccinate them.

Rotavirus gastroenteritis surveillance in Azerbaijan, 2011-2016

INTRODUCTION

Rotavirus is a leading cause of acute gastroenteritis and mortality among children worldwide but data describing rotavirus disease in Azerbaijan are lacking. This analysis describes the rotavirus disease burden in Baku, the largest city in Azerbaijan.

METHODS

We conducted active, prospective, sentinel hospital surveillance with laboratory confirmation for rotavirus among children under 5 years of age hospitalized at a large pediatric hospital in Baku during 2011-2016. Children with bloody diarrhea, or prior use of antibiotics or intravenous fluids were excluded. The guardians of enrolled children completed a questionnaire documenting clinical and demographic information. A stool specimen was collected from each enrolled child. We report the number and proportion of rotavirus positive hospitalizations during the surveillance period and a clinical description of rotavirus-positive and rotavirus-negative children.

RESULTS

From July 2011 through June 2016, 3139 children <5 years of age were enrolled into the surveillance system. Of these, 523 (17%) were positive for rotavirus, varying from 13% to 21% by surveillance year, with a median of 16% over the surveillance period. Increase in rotavirus detections occurred during December-May. Most rotavirus infections (303/523; 58%) occurred in children aged 6-23 months.

CONCLUSION

Rotavirus is responsible for approximately 16% of annual hospital admissions for acute gastroenteritis in children <5 years of age in Baku. This is lower than regional estimates. Exclusion of children with a history of antibiotic use or intravenous fluids may be accounting for this lower prevalence, and expansion of surveillance to include these groups could provide a more comprehensive picture of acute rotavirus gastroenteritis in Baku.

Vaccine coverage and compliance in Mexico with the two-dose and three-dose rotavirus vaccines

Worldwide, rotavirus infection has been a leading cause of severe diarrhea morbidity and mortality. Two rotavirus vaccines have been used in the National Immunization Program (NIP) in Mexico; two-dose Rotarix from 2006 to 2011 and three-dose RotaTeq since 2011. This study assessed coverage (receiving at least one dose or full dose series) in eligible infants, compliance (% completing dose series and % completing series on schedule) in eligible infants vaccinated with Rotarix (2010) versus RotaTeq (2012), using Mexican Social Security Institute data nationwide and by regions. In 2010, 80.7% received at least one dose of Rotarix, 75.6% received both doses and 57.0% received both doses on schedule. In 2012, 85.7% received at least one dose of RotaTeq, 61.0% received all three doses and 43.2% received all three doses on schedule. More eligible infants received all doses with Rotarix versus RotaTeq (p < 0.001). Among infants vaccinated with Rotarix versus RotaTeq, 93.7% versus 71.1% completed full series (p < 0.001), and 75.5% versus 70.9% completed full series on schedule (p = 0.105), respectively. The full series coverage and compliance decreased in all regions with RotaTeq compared with Rotarix. In conclusion, rotavirus vaccination has successfully reduced morbidity and mortality in children under 5 years in Mexico. This study found significant differences in full series coverage and compliance among infants and a higher proportion of completed scheduled at an earlier age in Mexico when comparing a two-dose vaccine in 2010 with a three-dose vaccine in 2012. Such differences might need to be taken into consideration to maximize NIP benefits, including early protection of the rotavirus vaccination program.

Impact of rotavirus vaccine introduction and genotypic characteristics of rotavirus strains in children less than 5 years of age with gastroenteritis in Ethiopia: 2011-2016

INTRODUCTION

A monovalent rotavirus vaccine was introduced in the Ethiopian Expanded Program on Immunization from November 2013. We compared impact of rotavirus vaccine introduction on rotavirus associated acute diarrhea hospitalizations and genotypic characteristics of rotavirus strains pre-and post-vaccine introduction.

METHODS

Sentinel surveillance for diarrhea among children <5 years of age was conducted at 3 hospitals in Addis Ababa, Ethiopia from 2011 to 2017. Stool specimens were collected from enrolled children and tested using an antigen capture enzyme immunoassay. Rotavirus positive samples (156 from pre- and 141 from post-vaccination periods) were further characterized by rotavirus genotyping methods to identify the predominant G and P types circulating during the surveillance era.

RESULTS

A total of 788 children were enrolled during the pre- (July 2011-June 2013) and 815 children during the post-vaccination (July 2014-June 2017) periods. The proportion of diarrhea hospitalizations due to rotavirus among children <5 years of age declined by 17% from 24% (188/788) in the pre-vaccine period and to 20% (161/185) in post-vaccine introduction era. Similarly, a reduction of 18% in proportion of diarrhea hospitalizations due to rotavirus in children <12 months of age in the post (27%) vs pre-vaccine (33%) periods was observed. Seasonal peaks of rotavirus declined following rotavirus vaccine introduction. The most prevalent circulating strains were G12P[8] in 2011 (36%) and in 2012 (27%), G2P[4] (35%) in 2013, G9P[8] (19%) in 2014, G3P[6] and G2P[4] (19% each) in 2015, and G3P[8] (29%) in 2016.

DISCUSSION

Following rotavirus vaccine introduction in Ethiopia, a reduction in rotavirus associated hospitalizations was seen in all age groups with the greatest burden in children <12 months of age. A wide variety of rotavirus strains circulated in the pre- and post-vaccine introduction periods.

Rotavirus diarrhoea hospitalizations among children under 5 years of age in Nigeria, 2011-2016

BACKGROUND

The high burden of rotavirus acute gastroenteritis (AGE) is well documented among children under 5 years of age, with the majority of mortality occurring in developing countries. Nigeria ranked second worldwide in the number of rotavirus deaths in 2013. As Nigeria plans to introduce rotavirus vaccine soon, a pre-vaccine documentation of rotavirus disease burden is necessary to determine vaccine impact.

METHODS

Routine rotavirus surveillance was conducted during 2011-2016 in 3 sentinel sites in Nigeria using the standard WHO protocol. Children under 5 years of age hospitalized for acute gastroenteritis were enrolled and demographic, clinical and outcome data were collected. A stool sample was subsequently obtained and tested for human rotavirus antigen using the Enzyme-linked immunosorbent assay (ELISA).

RESULTS

2694 children with acute gastroenteritis were enrolled during January 2011 to December 2016; of these, 1242 (46%) tested positive for rotavirus. Among the rotavirus positive cases, 66% and 94% were younger than 12 months and 24 months respectively. Marked peaks in rotavirus positivity were seen in January of each year. Vomiting, and use of oral and intravenous fluids occurred more often in rotavirus positive cases as compared to rotavirus negative cases.

CONCLUSION

The high prevalence of rotavirus disease highlights the need for urgent introduction of rotavirus vaccine in Nigeria. Additionally, this study provides pre-vaccine introduction disease-burden data that will serve as a baseline for rotavirus vaccine impact-assessment once vaccine has been introduced in the national immunization program.

Impact of rotavirus vaccine on diarrheal hospitalization and outpatient consultations in the Philippines: First evidence from a middle-income Asian country

•

Starting in 2012, RVV was introduced in public health clinics of Agusan del Sur province.

•

Declines in diarrheal hospitalizations and consults were seen following RVV introduction.

•

No declines in diarrheal admissions were observed in a province where RVV was not introduced.

•

This is the first evidence of the public health impact of RVV in a middle income country Asia.

Background

Monovalent rotavirus (RV) vaccine was introduced in the Philippines in a phased manner beginning in 2012. To assess the impact of RV vaccine, we conducted a retrospective review of diarrheal admissions in two hospitals.

Methods

Records of physician-diagnosed diarrheal admissions were reviewed in D.O. Plaza Hospital (DOPH) from 2009 to 2016 in Agusan del Sur where RV vaccine was introduced in the immunization program; and in Cotabato Regional Medical Center (CRMC) from 2011 to 2016 in a region where the vaccine was not introduced. Reports from consultations in public health clinics in Agusan Del Sur and RV vaccine coverage were obtained.

Results

All-cause diarrheal admissions among children <5 years old in DOPH declined from 2013 to 2016 following RV vaccine introduction in 2012. Using the 2009–2011 mean number of hospitalizations as baseline (X‾ = 1,141), the reductions were 28% (n = 821), 56% (n = 507), 63% (n = 417) and 59% (n = 466) in 2013, 2014, 2015 and 2016, respectively. In comparison, no substantial declines in diarrheal hospitalizations were seen in CRMC from 2011 to 2016. A declining trend was also seen in outpatient consultations in Agusan del Sur following RV vaccine introduction with declines of 27% (n = 2,333), 33% (n = 2,143), 45% (n = 1,764) and 67% (n = 1,059) in 2013, 2014, 2015 and 2016. From September 2012 to December 2016, the 1 and 2-dose RV vaccine coverage gradually increased from 5% and 4% in 2012 to 92% and 88% in 2015, but decreased in 2016 to 53% and 52%, respectively.

Discussion

RV vaccine introduction was associated with a substantial decline in diarrheal hospitalizations and outpatient consultations for diarrhea in Agusan del Sur, Philippines.

Clean water, clean hands or new vaccines?

Throughout human history, pathogens transmitted through feces from person to person have caused substantial mortality. Over a century ago civil engineers in high income countries developed approaches to collect and remove feces from the environment that in communities with high incomes and strong governments markedly reduced the burden of enteric disease. These approaches, however, have not been successfully extended to impoverished communities in low income countries. Water/sanitation/hygiene professionals have attempted, with only limited success, to reduce fecal exposure and human disease in the absence of definitive civil engineering approaches. Medical professionals have worked to develop vaccines against some of the most important fecal oral pathogens. Each of these approaches needs further development and adaptation to optimally address the burden of fecally transmitted diseases in impoverished communities.

Impact of rotavirus vaccines in low and middle-income countries

PURPOSE OF REVIEW

Rotavirus vaccines are playing a pivotal role in improving lives of infants and young children in low and middle-income countries (LMICs). Many of these countries have adopted the vaccine into their routine immunization, whereas others are considering introduction. This article provides an update on the impact of rotavirus vaccines in LMICs on morbidity and mortality in children aged less than 5 years, and their cost-effectiveness.

RECENT FINDINGS

The WHO, in 2013, updated its recommendation to prioritize introduction of rotavirus vaccines in the routine immunization schedule, without age restrictions. Despite the decreased efficacy of the vaccines in LMICs, data from Sub-Saharan Africa have demonstrated a decrease in rotavirus-related morbidity, with some sites reporting an indirect protective effect on children age ineligible to receive the vaccine. Even with improvements in sanitation, nutritional status in children, and other health-related indices in LMICs, the use of rotavirus vaccines will play an important role in preventing rotavirus-related gastroenteritis. Economic models predict a reduction in economic burden because of rotavirus-related health costs, making vaccine introduction cost-effective in resource-constrained settings.

SUMMARY

Increasing evidence from impact studies shows the significant impact of rotavirus vaccination on hospitalizations and economic burden because of rotavirus gastroenteritis in LMICs. Universal rotavirus vaccination is recommended, and introductions should be monitored by robust surveillance systems to measure effectiveness and impact.

The global problem of childhood diarrhoeal diseases: emerging strategies in prevention and management

Acute diarrhoeal diseases remain a leading cause of global morbidity and mortality particularly among young children in resource-limited countries. Recent large studies utilizing case-control design, prospective sampling and more sensitive and broad diagnostic techniques have shed light on particular pathogens of importance and highlighted the previously under recognized impact of these infections on post-acute illness mortality and growth. Vaccination, particularly against rotavirus, has emerged as a key effective means of preventing significant morbidity and mortality from childhood diarrhoeal disease. Other candidate vaccines against leading diarrhoeal pathogens, such as enterotoxigenic Escherichia coli and Shigella spp., also hold significant promise in further ameliorating the burden of enteric infections in children. Large studies are also currently underway evaluating novel and potential easy-to-implement water, sanitation and hygiene (WASH) preventive strategies. Given the ongoing global burden of this illness, the paucity of new advances in case management over the last several decades remains a challenge. The increasing recognition of post-acute illness mortality and growth impairment has highlighted the need for interventions that go beyond management of dehydration and electrolyte disturbances. The few trials of novel promising interventions such as probiotics have mainly been conducted in high-income settings. Trials of antimicrobials have also been primarily conducted in high-income settings or in travellers from high-income settings. Bloody diarrhoea has been shown to be a poor marker of potentially treatable bacterial enteritis, and rising antimicrobial resistance has also made empiric antimicrobial therapy more challenging in many settings. Novel effective and sustainable interventions and diagnostic strategies are clearly needed to help improve case management. Diarrhoeal disease and other enteric infections remain an unmet challenge in global child health. Most promising recent developments have been focused around preventive measures, in particular vaccination. Further advances in prevention and case management including the possible use of targeted antimicrobial treatment are also required to fully address this critical burden on child health and human potential.

Feasibility of using regional sentinel surveillance to monitor the rotavirus vaccine impact, effectiveness and intussusception incidence in the African Region

The 9th African rotavirus symposium was held in Maputo, Mozambique from the 8th to 10th of December 2015, including a total of 101 delegates from 17 countries, 15 of which were African countries. This forum brought together participants with various expertise including scientists, clinicians, immunization program managers, public health officials and policymakers. By the time of the symposium, 29/47 (61%) of countries in the World Health Organization (WHO) African Region had introduced rotavirus vaccine into their routine immunization program. Countries that had started monitoring impact and effectiveness of the rotavirus vaccines as well as potential adverse events following immunization (AEFI) including intussusception) also participated. Seven Rotarix® vaccine-using countries and another four countries that are using the Rotateq® vaccine are conducting systematic surveillance on intussusception and report data to the WHO and partners. The symposium concluded that the regional rotavirus surveillance network has played a crucial role in pre-vaccine data through documenting burden and epidemiology of rotavirus diarrhea in Africa, seasonal trends and identifying common rotavirus genotypes. The sentinel surveillance platform is now being used to assess the impact of the vaccines and monitoring adverse events with a focus on intussusception.

[A plasmid-based reverse genetics system for rotaviruses]

Rotavirus (RV), a non-enveloped icosahedral virus containing eleven gene segments of double-stranded RNA, is the leading cause of severe, acute diarrhea among infants and young children worldwide. Safe and effective rotavirus vaccines have been available since 2006, and have markedly reduced the number of deaths by severe gastroenteritis. However, rotaviruses are still responsible for approximately 200,000 deaths annually worldwide. Reverse genetics systems for the manipulation of viral genomes are a powerful approach for studying viral replication and pathogenesis, and for developing vaccines and viral vectors. The understanding of the molecular mechanisms underlying RV pathogenesis, or development of next generation vaccines, has been hampered by the lack of a complete reverse genetics system. Recently, we developed a novel reverse genetics system which enabled recovery of recombinant RVs entirely from cloned cDNAs. This new strategy requires co-expression of a small transmembrane protein that accelerates cell-to-cell fusion and vaccinia virus capping enzyme. In this review, the strategies and history of the development of reverse genetics systems for the family Reoviridae are described.

Rotavirus vaccines: current global impact and future perspectives

As of May 2016, 81 countries have introduced Rotarix or RotaTeq rotavirus vaccines into their national immunization program. Despite initially slow uptake in some countries and differences in vaccine effectiveness (VE) between high-, low- and middle-income countries, impact of the vaccines has been swift and striking in all settings, with good VE against vaccine-type and nonvaccine-type strains. Newly published research indicates poor nutrition is associated with decreased VE and breastfeeding at the time of vaccination does not affect vaccine response. Vaccines in development and proposed alternate schedules also promise to address limitations of the current vaccines and optimize rotavirus disease prevention.