Vaccines for preventing rotavirus diarrhoea: vaccines in use

Intestinal Parasitic Infections Among Pediatric Patients in a Metropolitan City of Bangladesh With Emphasis on Cryptosporidiosis

Introduction

Gastrointestinal parasitic infections are one of the global health concerns in developing countries like Bangladesh. Among them, Cryptosporidium spp. plays an essential role in causing diarrhea, malnutrition, and poor cognitive function, especially in children. This study was conducted to identify the frequency of Cryptosporidium cases and other parasitic agents. 

Methods

A cross-sectional observational study was conducted among 219 hospitalized children with diarrhea. The conventional microscopic technique was applied for parasitic detection. Particular staining (modified Ziehl-Neelsen) procedure was performed to identify oocysts of Cryptosporidium spp. A polymerase chain reaction (PCR) was performed to determine the SSU rRNA and gp60 gene of Cryptosporidium. 

Results

Cysts of Giardia duodenalis (2.3%), ova of Ascaris lumbricoides (1.4%,), Trichuris trichiura (0.5%), and both A. lumbricoides and T. trichiura (0.9%) were identified in samples through wet mount preparation. The distribution of Cryptosporidium spp. as detected by the staining method and nested PCR was 1.4% and 4.1%, respectively. 

Conclusion

Factors independently associated with Cryptosporidium infection are unsafe water, lack of regular hand washing, and insufficiency of exclusive breastfeeding. This study reports, presumably for the first time, the detection of Cryptosporidium oocysts in Chattogram metropolitan city of Bangladesh.

Vaccines for preventing rotavirus diarrhoea: vaccines in use

BACKGROUND

Rotavirus is a common cause of diarrhoea, diarrhoea-related hospital admissions, and diarrhoea-related deaths worldwide. Rotavirus vaccines prequalified by the World Health Organization (WHO) include Rotarix (GlaxoSmithKline), RotaTeq (Merck), and, more recently, Rotasiil (Serum Institute of India Ltd.), and Rotavac (Bharat Biotech Ltd.).

OBJECTIVES

To evaluate rotavirus vaccines prequalified by the WHO for their efficacy and safety in children.

SEARCH METHODS

On 30 November 2020, we searched PubMed, the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (published in the Cochrane Library), Embase, LILACS, Science Citation Index Expanded, Social Sciences Citation Index, Conference Proceedings Citation Index-Science, Conference Proceedings Citation Index-Social Science & Humanities. We also searched the WHO ICTRP, ClinicalTrials.gov, clinical trial reports from manufacturers' websites, and reference lists of included studies, and relevant systematic reviews.

SELECTION CRITERIA

We selected randomized controlled trials (RCTs) conducted in children that compared rotavirus vaccines prequalified for use by the WHO with either placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and assessed risk of bias. One author extracted data and a second author cross-checked them. We combined dichotomous data using the risk ratio (RR) and 95% confidence interval (CI). We stratified the analyses by under-five country mortality rate and used GRADE to evaluate evidence certainty.

MAIN RESULTS

Sixty trials met the inclusion criteria and enrolled a total of 228,233 participants. Thirty-six trials (119,114 participants) assessed Rotarix, 15 trials RotaTeq (88,934 participants), five trials Rotasiil (11,753 participants), and four trials Rotavac (8432 participants). Rotarix Infants vaccinated and followed up for the first year of life In low-mortality countries, Rotarix prevented 93% of severe rotavirus diarrhoea cases (14,976 participants, 4 trials; high-certainty evidence), and 52% of severe all-cause diarrhoea cases (3874 participants, 1 trial; moderate-certainty evidence).  In medium-mortality countries, Rotarix prevented 79% of severe rotavirus diarrhoea cases (31,671 participants, 4 trials; high-certainty evidence), and 36% of severe all-cause diarrhoea cases (26,479 participants, 2 trials; high-certainty evidence).  In high-mortality countries, Rotarix prevented 58% of severe rotavirus diarrhoea cases (15,882 participants, 4 trials; high-certainty evidence), and 27% of severe all-cause diarrhoea cases (5639 participants, 2 trials; high-certainty evidence). Children vaccinated and followed up for two years In low-mortality countries, Rotarix prevented 90% of severe rotavirus diarrhoea cases (18,145 participants, 6 trials; high-certainty evidence), and 51% of severe all-cause diarrhoea episodes (6269 participants, 2 trials; moderate-certainty evidence).   In medium-mortality countries, Rotarix prevented 77% of severe rotavirus diarrhoea cases (28,834 participants, 3 trials; high-certainty evidence), and 26% of severe all-cause diarrhoea cases (23,317 participants, 2 trials; moderate-certainty evidence).  In high-mortality countries, Rotarix prevented 35% of severe rotavirus diarrhoea cases (13,768 participants, 2 trials; moderate-certainty evidence), and 17% of severe all-cause diarrhoea cases (2764 participants, 1 trial; high-certainty evidence). RotaTeq Infants vaccinated and followed up for the first year of life In low-mortality countries, RotaTeq prevented 97% of severe rotavirus diarrhoea cases (5442 participants, 2 trials; high-certainty evidence).  In medium-mortality countries, RotaTeq prevented 79% of severe rotavirus diarrhoea cases (3863 participants, 1 trial; low-certainty evidence).  In high-mortality countries, RotaTeq prevented 57% of severe rotavirus diarrhoea cases (6775 participants, 2 trials; high-certainty evidence), but there is probably little or no difference between vaccine and placebo for severe all-cause diarrhoea (1 trial, 4085 participants; moderate-certainty evidence).  Children vaccinated and followed up for two years In low-mortality countries, RotaTeq prevented 96% of severe rotavirus diarrhoea cases (5442 participants, 2 trials; high-certainty evidence).  In medium-mortality countries, RotaTeq prevented 79% of severe rotavirus diarrhoea cases (3863 participants, 1 trial; low-certainty evidence).  In high-mortality countries, RotaTeq prevented 44% of severe rotavirus diarrhoea cases (6744 participants, 2 trials; high-certainty evidence), and 15% of severe all-cause diarrhoea cases (5977 participants, 2 trials; high-certainty evidence).  We did not identify RotaTeq studies reporting on severe all-cause diarrhoea in low- or medium-mortality countries. Rotasiil Rotasiil has not been assessed in any RCT in countries with low or medium child mortality. Infants vaccinated and followed up for the first year of life In high-mortality countries, Rotasiil prevented 48% of severe rotavirus diarrhoea cases (11,008 participants, 2 trials; high-certainty evidence), and resulted in little to no difference in severe all-cause diarrhoea cases (11,008 participants, 2 trials; high-certainty evidence). Children vaccinated and followed up for two years In high-mortality countries, Rotasiil prevented 44% of severe rotavirus diarrhoea cases (11,008 participants, 2 trials; high-certainty evidence), and resulted in little to no difference in severe all-cause diarrhoea cases (11,008 participants, 2 trials; high-certainty evidence). Rotavac Rotavac has not been assessed in any RCT in countries with low or medium child mortality.  Infants vaccinated and followed up for the first year of life In high-mortality countries, Rotavac prevented 57% of severe rotavirus diarrhoea cases (6799 participants, 1 trial; moderate-certainty evidence), and 16% of severe all-cause diarrhoea cases (6799 participants, 1 trial; moderate-certainty evidence). Children vaccinated and followed up for two years In high-mortality countries, Rotavac prevented 54% of severe rotavirus diarrhoea cases (6541 participants, 1 trial; moderate-certainty evidence); no Rotavac studies have reported on severe all-cause diarrhoea at two-years follow-up. Safety No increased risk of serious adverse events (SAEs) was detected with Rotarix (103,714 participants, 31 trials; high-certainty evidence), RotaTeq (82,502 participants, 14 trials; moderate to high-certainty evidence), Rotasiil (11,646 participants, 3 trials; high-certainty evidence), or Rotavac (8210 participants, 3 trials; moderate-certainty evidence). Deaths were infrequent and the analysis had insufficient evidence to show an effect on all-cause mortality. Intussusception was rare.  AUTHORS' CONCLUSIONS: Rotarix, RotaTeq, Rotasiil, and Rotavac prevent episodes of rotavirus diarrhoea. The relative effect estimate is smaller in high-mortality than in low-mortality countries, but more episodes are prevented in high-mortality settings as the baseline risk is higher. In high-mortality countries some results suggest lower efficacy in the second year. We found no increased risk of serious adverse events, including intussusception, from any of the prequalified rotavirus vaccines.

Vaccines for preventing rotavirus diarrhoea: vaccines in use

BACKGROUND

Rotavirus results in more diarrhoea-related deaths in children under five years than any other single agent in countries with high childhood mortality. It is also a common cause of diarrhoea-related hospital admissions in countries with low childhood mortality. Rotavirus vaccines that have been prequalified by the World Health Organization (WHO) include a monovalent vaccine (RV1; Rotarix, GlaxoSmithKline), a pentavalent vaccine (RV5; RotaTeq, Merck), and, more recently, another monovalent vaccine (Rotavac, Bharat Biotech).

OBJECTIVES

To evaluate rotavirus vaccines prequalified by the WHO (RV1, RV5, and Rotavac) for their efficacy and safety in children.

SEARCH METHODS

On 4 April 2018 we searched MEDLINE (via PubMed), the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (published in the Cochrane Library), Embase, LILACS, and BIOSIS. We also searched the WHO ICTRP, ClinicalTrials.gov, clinical trial reports from manufacturers' websites, and reference lists of included studies and relevant systematic reviews.

SELECTION CRITERIA

We selected randomized controlled trials (RCTs) in children comparing rotavirus vaccines prequalified for use by the WHO versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and assessed risks of bias. One review author extracted data and a second author cross-checked them. We combined dichotomous data using the risk ratio (RR) and 95% confidence interval (CI). We stratified the analysis by country mortality rate and used GRADE to evaluate evidence certainty.

MAIN RESULTS

Fifty-five trials met the inclusion criteria and enrolled a total of 216,480 participants. Thirty-six trials (119,114 participants) assessed RV1, 15 trials (88,934 participants) RV5, and four trials (8432 participants) Rotavac. RV1 Children vaccinated and followed up the first year of life In low-mortality countries, RV1 prevents 84% of severe rotavirus diarrhoea cases (RR 0.16, 95% CI 0.09 to 0.26; 43,779 participants, 7 trials; high-certainty evidence), and probably prevents 41% of cases of severe all-cause diarrhoea (RR 0.59, 95% CI 0.47 to 0.74; 28,051 participants, 3 trials; moderate-certainty evidence). In high-mortality countries, RV1 prevents 63% of severe rotavirus diarrhoea cases (RR 0.37, 95% CI 0.23 to 0.60; 6114 participants, 3 trials; high-certainty evidence), and 27% of severe all-cause diarrhoea cases (RR 0.73, 95% CI 0.56 to 0.95; 5639 participants, 2 trials; high-certainty evidence). Children vaccinated and followed up for two years In low-mortality countries, RV1 prevents 82% of severe rotavirus diarrhoea cases (RR 0.18, 95% CI 0.14 to 0.23; 36,002 participants, 9 trials; high-certainty evidence), and probably prevents 37% of severe all-cause diarrhoea episodes (rate ratio 0.63, 95% CI 0.56 to 0.71; 39,091 participants, 2 trials; moderate-certainty evidence). In high-mortality countries RV1 probably prevents 35% of severe rotavirus diarrhoea cases (RR 0.65, 95% CI 0.51 to 0.83; 13,768 participants, 2 trials; high-certainty evidence), and 17% of severe all-cause diarrhoea cases (RR 0.83, 95% CI 0.72 to 0.96; 2764 participants, 1 trial; moderate-certainty evidence). No increased risk of serious adverse events (SAE) was detected (RR 0.88 95% CI 0.83 to 0.93; high-certainty evidence). There were 30 cases of intussusception reported in 53,032 children after RV1 vaccination and 28 cases in 44,214 children after placebo or no intervention (RR 0.70, 95% CI 0.46 to 1.05; low-certainty evidence). RV5 Children vaccinated and followed up the first year of life In low-mortality countries, RV5 probably prevents 92% of severe rotavirus diarrhoea cases (RR 0.08, 95% CI 0.03 to 0.22; 4132 participants, 5 trials; moderate-certainty evidence). We did not identify studies reporting on severe all-cause diarrhoea in low-mortality countries. In high-mortality countries, RV5 prevents 57% of severe rotavirus diarrhoea (RR 0.43, 95% CI 0.29 to 0.62; 5916 participants, 2 trials; high-certainty evidence), but there is probably little or no difference between vaccine and placebo for severe all-cause diarrhoea (RR 0.80, 95% CI 0.58 to 1.11; 1 trial, 4085 participants; moderate-certainty evidence). Children vaccinated and followed up for two years In low-mortality countries, RV5 prevents 82% of severe rotavirus diarrhoea cases (RR 0.18, 95% CI 0.08 to 0.39; 7318 participants, 4 trials; moderate-certainty evidence). We did not identify studies reporting on severe all-cause diarrhoea in low-mortality countries. In high-mortality countries, RV5 prevents 41% of severe rotavirus diarrhoea cases (RR 0.59, 95% CI 0.43 to 0.82; 5885 participants, 2 trials; high-certainty evidence), and 15% of severe all-cause diarrhoea cases (RR 0.85, 95% CI 0.75 to 0.98; 5977 participants, 2 trials; high-certainty evidence). No increased risk of serious adverse events (SAE) was detected (RR 0.93 95% CI 0.86 to 1.01; moderate to high-certainty evidence). There were 16 cases of intussusception in 43,629 children after RV5 vaccination and 20 cases in 41,866 children after placebo (RR 0.77, 95% CI 0.41 to 1.45; low-certainty evidence). Rotavac Children vaccinated and followed up the first year of life Rotavac has not been assessed in any RCT in countries with low child mortality. In India, a high-mortality country, Rotavac probably prevents 57% of severe rotavirus diarrhoea cases (RR 0.43, 95% CI 0.30 to 0.60; 6799 participants, moderate-certainty evidence); the trial did not report on severe all-cause diarrhoea at one-year follow-up. Children vaccinated and followed up for two years Rotavac probably prevents 54% of severe rotavirus diarrhoea cases in India (RR 0.46, 95% CI 0.35 to 0.60; 6541 participants, 1 trial; moderate-certainty evidence), and 16% of severe all-cause diarrhoea cases (RR 0.84, 95% CI 0.71 to 0.98; 6799 participants, 1 trial; moderate-certainty evidence). No increased risk of serious adverse events (SAE) was detected (RR 0.93 95% CI 0.85 to 1.02; moderate-certainty evidence). There were eight cases of intussusception in 5764 children after Rotavac vaccination and three cases in 2818 children after placebo (RR 1.33, 95% CI 0.35 to 5.02; very low-certainty evidence). There was insufficient evidence of an effect on mortality from any rotavirus vaccine (198,381 participants, 44 trials; low- to very low-certainty evidence), as the trials were not powered to detect an effect at this endpoint.

AUTHORS' CONCLUSIONS

RV1, RV5, and Rotavac prevent episodes of rotavirus diarrhoea. Whilst the relative effect estimate is smaller in high-mortality than in low-mortality countries, there is a greater number of episodes prevented in these settings as the baseline risk is much higher. We found no increased risk of serious adverse events. 21 October 2019 Up to date All studies incorporated from most recent search All published trials found in the last search (4 Apr, 2018) were included and 15 ongoing studies are currently awaiting completion (see 'Characteristics of ongoing studies').

Vaccines for preventing rotavirus diarrhoea: vaccines in use

BACKGROUND

Rotavirus results in more diarrhoea-related deaths in children under five years than any other single agent in countries with high childhood mortality. It is also a common cause of diarrhoea-related hospital admissions in countries with low childhood mortality. Rotavirus vaccines that have been prequalified by the World Health Organization (WHO) include a monovalent vaccine (RV1; Rotarix, GlaxoSmithKline), a pentavalent vaccine (RV5; RotaTeq, Merck), and, more recently, another monovalent vaccine (Rotavac, Bharat Biotech).

OBJECTIVES

To evaluate rotavirus vaccines prequalified by the WHO (RV1, RV5, and Rotavac) for their efficacy and safety in children.

SEARCH METHODS

On 4 April 2018 we searched MEDLINE (via PubMed), the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (published in the Cochrane Library), Embase, LILACS, and BIOSIS. We also searched the WHO ICTRP, ClinicalTrials.gov, clinical trial reports from manufacturers' websites, and reference lists of included studies and relevant systematic reviews.

SELECTION CRITERIA

We selected randomized controlled trials (RCTs) in children comparing rotavirus vaccines prequalified for use by the WHO versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and assessed risks of bias. One review author extracted data and a second author cross-checked them. We combined dichotomous data using the risk ratio (RR) and 95% confidence interval (CI). We stratified the analysis by country mortality rate and used GRADE to evaluate evidence certainty.

MAIN RESULTS

Fifty-five trials met the inclusion criteria and enrolled a total of 216,480 participants. Thirty-six trials (119,114 participants) assessed RV1, 15 trials (88,934 participants) RV5, and four trials (8432 participants) Rotavac.RV1 Children vaccinated and followed up the first year of life In low-mortality countries, RV1 prevents 84% of severe rotavirus diarrhoea cases (RR 0.16, 95% CI 0.09 to 0.26; 43,779 participants, 7 trials; high-certainty evidence), and probably prevents 41% of cases of severe all-cause diarrhoea (RR 0.59, 95% CI 0.47 to 0.74; 28,051 participants, 3 trials; moderate-certainty evidence). In high-mortality countries, RV1 prevents 63% of severe rotavirus diarrhoea cases (RR 0.37, 95% CI 0.23 to 0.60; 6114 participants, 3 trials; high-certainty evidence), and 27% of severe all-cause diarrhoea cases (RR 0.73, 95% CI 0.56 to 0.95; 5639 participants, 2 trials; high-certainty evidence).Children vaccinated and followed up for two yearsIn low-mortality countries, RV1 prevents 82% of severe rotavirus diarrhoea cases (RR 0.18, 95% CI 0.14 to 0.23; 36,002 participants, 9 trials; high-certainty evidence), and probably prevents 37% of severe all-cause diarrhoea episodes (rate ratio 0.63, 95% CI 0.56 to 0.71; 39,091 participants, 2 trials; moderate-certainty evidence). In high-mortality countries RV1 probably prevents 35% of severe rotavirus diarrhoea cases (RR 0.65, 95% CI 0.51 to 0.83; 13,768 participants, 2 trials; high-certainty evidence), and 17% of severe all-cause diarrhoea cases (RR 0.83, 95% CI 0.72 to 0.96; 2764 participants, 1 trial; moderate-certainty evidence).No increased risk of serious adverse events (SAE) was detected (RR 0.88 95% CI 0.83 to 0.93; high-certainty evidence). There were 30 cases of intussusception reported in 53,032 children after RV1 vaccination and 28 cases in 44,214 children after placebo or no intervention (RR 0.70, 95% CI 0.46 to 1.05; low-certainty evidence).RV5 Children vaccinated and followed up the first year of life In low-mortality countries, RV5 probably prevents 92% of severe rotavirus diarrhoea cases (RR 0.08, 95% CI 0.03 to 0.22; 4132 participants, 5 trials; moderate-certainty evidence). We did not identify studies reporting on severe all-cause diarrhoea in low-mortality countries. In high-mortality countries, RV5 prevents 57% of severe rotavirus diarrhoea (RR 0.43, 95% CI 0.29 to 0.62; 5916 participants, 2 trials; high-certainty evidence), but there is probably little or no difference between vaccine and placebo for severe all-cause diarrhoea (RR 0.80, 95% CI 0.58 to 1.11; 1 trial, 4085 participants; moderate-certainty evidence).Children vaccinated and followed up for two yearsIn low-mortality countries, RV5 prevents 82% of severe rotavirus diarrhoea cases (RR 0.18, 95% CI 0.08 to 0.39; 7318 participants, 4 trials; moderate-certainty evidence). We did not identify studies reporting on severe all-cause diarrhoea in low-mortality countries. In high-mortality countries, RV5 prevents 41% of severe rotavirus diarrhoea cases (RR 0.59, 95% CI 0.43 to 0.82; 5885 participants, 2 trials; high-certainty evidence), and 15% of severe all-cause diarrhoea cases (RR 0.85, 95% CI 0.75 to 0.98; 5977 participants, 2 trials; high-certainty evidence).No increased risk of serious adverse events (SAE) was detected (RR 0.93 95% CI 0.86 to 1.01; moderate to high-certainty evidence). There were 16 cases of intussusception in 43,629 children after RV5 vaccination and 20 cases in 41,866 children after placebo (RR 0.77, 95% CI 0.41 to 1.45; low-certainty evidence).Rotavac Children vaccinated and followed up the first year of life Rotavac has not been assessed in any RCT in countries with low child mortality. In India, a high-mortality country, Rotavac probably prevents 57% of severe rotavirus diarrhoea cases (RR 0.43, 95% CI 0.30 to 0.60; 6799 participants, moderate-certainty evidence); the trial did not report on severe all-cause diarrhoea at one-year follow-up.Children vaccinated and followed up for two yearsRotavac probably prevents 54% of severe rotavirus diarrhoea cases in India (RR 0.46, 95% CI 0.35 to 0.60; 6541 participants, 1 trial; moderate-certainty evidence), and 16% of severe all-cause diarrhoea cases (RR 0.84, 95% CI 0.71 to 0.98; 6799 participants, 1 trial; moderate-certainty evidence).No increased risk of serious adverse events (SAE) was detected (RR 0.93 95% CI 0.85 to 1.02; moderate-certainty evidence). There were eight cases of intussusception in 5764 children after Rotavac vaccination and three cases in 2818 children after placebo (RR 1.33, 95% CI 0.35 to 5.02; very low-certainty evidence).There was insufficient evidence of an effect on mortality from any rotavirus vaccine (198,381 participants, 44 trials; low- to very low-certainty evidence), as the trials were not powered to detect an effect at this endpoint.

AUTHORS' CONCLUSIONS

RV1, RV5, and Rotavac prevent episodes of rotavirus diarrhoea. Whilst the relative effect estimate is smaller in high-mortality than in low-mortality countries, there is a greater number of episodes prevented in these settings as the baseline risk is much higher. We found no increased risk of serious adverse events.

Prospects for rotavirus vaccine introduction in the Philippines: Bridging the available evidence into immunization policy

Rotavirus (RV) diarrhea is one of the most common cause of childhood morbidity and mortality in the world. The World Health Organization has recommended RV vaccines’ use in national immunization programs since 2009. However, access to vaccines remain limited, particularly for most low- and middle-income countries where the burden of the disease is high. The Philippines is a lower-middle income country in Asia where RV vaccination remains limited. Recent studies in the Philippines indicate an estimated vaccine effectiveness of 60% against RV hospitalization, and a 50–60% reduction of all cause diarrhea among children aged under 5 within the population. Furthermore, we estimate that 225 rotavirus cases can be prevented per 1000 children vaccinated against RV. This information will be crucial as policymakers decide on expanding RV vaccination nationwide.

Therapeutics and Immunoprophylaxis Against Noroviruses and Rotaviruses: The Past, Present, and Future

Background:

Noroviruses and rotaviruses are important viral etiologies of severe gastroenteritis. Noroviruses are the primary cause of nonbacterial diarrheal outbreaks in humans, whilst rotaviruses are a major cause of childhood diarrhea. Although both enteric pathogens substantially impact human health and economies, there are no approved drugs against noroviruses and rotaviruses so far. On the other hand, whilst the currently licensed rotavirus vaccines have been successfully implemented in over 100 countries, the most advanced norovirus vaccine has recently completed phase-I and II trials.

Methods:

We performed a structured search of bibliographic databases for peer-reviewed research litera-ture on advances in the fields of norovirus and rotavirus therapeutics and immunoprophylaxis.

Results:

Technological advances coupled with a proper understanding of viral morphology and replication over the past decade has facilitated pioneering research on therapeutics and immunoprophylaxis against noroviruses and rotaviruses, with promising outcomes in human clinical trials of some of the drugs and vaccines. This review focuses on the various developments in the fields of norovirus and rotavirus thera-peutics and immunoprophylaxis, such as potential antiviral drug molecules, passive immunotherapies (oral human immunoglobulins, egg yolk and bovine colostral antibodies, llama-derived nanobodies, and anti-bodies expressed in probiotics, plants, rice grains and insect larvae), immune system modulators, probiot-ics, phytochemicals and other biological substances such as bovine milk proteins, therapeutic nanoparti-cles, hydrogels and viscogens, conventional viral vaccines (live and inactivated whole virus vaccines), and genetically engineered viral vaccines (reassortant viral particles, virus-like particles (VLPs) and other sub-unit recombinant vaccines including multi-valent viral vaccines, edible plant vaccines, and encapsulated viral particles).

Conclusions:

This review provides important insights into the various approaches to therapeutics and im-munoprophylaxis against noroviruses and rotaviruses..

Cost-effectiveness analysis of diarrhoea management approaches in Nigeria: A decision analytical model

BACKGROUND

Diarrhoea is a leading cause of death in Nigerian children under 5 years. Implementing the most cost-effective approach to diarrhoea management in Nigeria will help optimize health care resources allocation. This study evaluated the cost-effectiveness of various approaches to diarrhoea management namely: the 'no treatment' approach (NT); the preventive approach with rotavirus vaccine; the integrated management of childhood illness for diarrhoea approach (IMCI); and rotavirus vaccine plus integrated management of childhood illness for diarrhoea approach (rotavirus vaccine + IMCI).

METHODS

Markov cohort model conducted from the payer's perspective was used to calculate the cost-effectiveness of the four interventions. The markov model simulated a life cycle of 260 weeks for 33 million children under five years at risk of having diarrhoea (well state). Disability adjusted life years (DALYs) averted was used to quantify clinical outcome. Incremental cost-effectiveness ratio (ICER) served as measure of cost-effectiveness.

RESULTS

Based on cost-effectiveness threshold of $2,177.99 (i.e. representing Nigerian GDP/capita), all the approaches were very cost-effective but rotavirus vaccine approach was dominated. While IMCI has the lowest ICER of $4.6/DALY averted, the addition of rotavirus vaccine was cost-effective with an ICER of $80.1/DALY averted. Rotavirus vaccine alone was less efficient in optimizing health care resource allocation.

CONCLUSION

Rotavirus vaccine + IMCI approach was the most cost-effective approach to childhood diarrhoea management. Its awareness and practice should be promoted in Nigeria. Addition of rotavirus vaccine should be considered for inclusion in the national programme of immunization. Although our findings suggest that addition of rotavirus vaccine to IMCI for diarrhoea is cost-effective, there may be need for further vaccine demonstration studies or real life studies to establish the cost-effectiveness of the vaccine in Nigeria.

Anti-infective activities of lactobacillus strains in the human intestinal microbiota: from probiotics to gastrointestinal anti-infectious biotherapeutic agents

A vast and diverse array of microbial species displaying great phylogenic, genomic, and metabolic diversity have colonized the gastrointestinal tract. Resident microbes play a beneficial role by regulating the intestinal immune system, stimulating the maturation of host tissues, and playing a variety of roles in nutrition and in host resistance to gastric and enteric bacterial pathogens. The mechanisms by which the resident microbial species combat gastrointestinal pathogens are complex and include competitive metabolic interactions and the production of antimicrobial molecules. The human intestinal microbiota is a source from which Lactobacillus probiotic strains have often been isolated. Only six probiotic Lactobacillus strains isolated from human intestinal microbiota, i.e., L. rhamnosus GG, L. casei Shirota YIT9029, L. casei DN-114 001, L. johnsonii NCC 533, L. acidophilus LB, and L. reuteri DSM 17938, have been well characterized with regard to their potential antimicrobial effects against the major gastric and enteric bacterial pathogens and rotavirus. In this review, we describe the current knowledge concerning the experimental antibacterial activities, including antibiotic-like and cell-regulating activities, and therapeutic effects demonstrated in well-conducted, placebo-controlled, randomized clinical trials of these probiotic Lactobacillus strains. What is known about the antimicrobial activities supported by the molecules secreted by such probiotic Lactobacillus strains suggests that they constitute a promising new source for the development of innovative anti-infectious agents that act luminally and intracellularly in the gastrointestinal tract.

The Effect of Mass Azithromycin Distribution on Childhood Mortality: Beliefs and Estimates of Efficacy

A cluster-randomized trial demonstrated that mass oral azithromycin distribution reduced childhood mortality 49.6% (Trachoma Amelioration in Northern Amhara [TANA]). The relative risk of childhood mortality was then estimated using two approaches: an expert survey and a Bayesian analysis. The survey asked public health experts to estimate the true effect of mass azithromycin distribution on childhood mortality. The Bayesian estimation used the TANA study's results and prior estimates of the efficacy of other effective population-level interventions. The experts believed mass azithromycin reduces childhood mortality (relative risk = 0.83, 95% credible intervals [CrI] = 0.70-1.00). The Bayesian analysis estimated a relative risk of 0.71 (95% CrI = 0.39-0.93). Both estimates suggest that azithromycin may have a true mortality benefit, though of a smaller magnitude than found in the single available trial. Prior information about nonantibiotic, population-level interventions may have informed the expert's opinions. Additional trials are needed to confirm a mortality benefit from mass azithromycin.

Selecting vaccine strains for H3N2 human influenza A virus

H3N2 human influenza A virus causes epidemics of influenza mainly in the winter season in temperate regions. Since the antigenicity of this virus evolves rapidly, several attempts have been made to predict the major amino acid sequence of hemagglutinin 1 (HA1) in the target season of vaccination. However, the usefulness of predicted sequence was unclear because its relationship to the antigenicity was unknown. Here the antigenic model for estimating the degree of antigenic difference (antigenic distance) between amino acid sequences of HA1 was integrated into the process of selecting vaccine strains for H3N2 human influenza A virus. When the effectiveness of a potential vaccine strain for a target season was evaluated retrospectively using the average antigenic distance between the strain and the epidemic viruses sampled in the target season, the most effective vaccine strain was identified mostly in the season one year before the target season (pre-target season). Effectiveness of actual vaccines appeared to be lower than that of the strains randomly chosen in the pre-target season on average. It was recommended to replace the vaccine strain for every target season with the strain having the smallest average antigenic distance to the others in the pre-target season. The procedure of selecting vaccine strains for future epidemic seasons described in the present study was implemented in the influenza virus forecasting system (INFLUCAST) (http://www.nsc.nagoya-cu.ac.jp/~yossuzuk/influcast.html).

Flagellin in fusion with human rotavirus structural proteins exerts an adjuvant effect when delivered with replicating but non-disseminating adenovectors through the intrarectal route

Human rotavirus (HRV) is the worldwide leading cause of gastroenteritis in young children. Two live attenuated HRV vaccines have been approved since 2006. However, these live vaccines still have potential risks including reversion of virulence. Adenoviruses are suitable vectors for mucosal administration of subunit vaccines. In addition to the adjuvant effect of certain adenovirus components, the use of an adjuvant like flagellin is also another means to increase the immune response to the immunogen. The aim of this study was to determine whether flagellin in fusion with HRV structural proteins stimulates the innate immune response and enhances the HRV-specific immune response when delivered through the intrarectal route with replicating but non-disseminating adenovector (R-AdV). Salmonella typhimurium flagellin B (FljB) in fusion with HRV VP4Δ::VP7 protein induced IL-1β production in J774A.1 macrophages exposed to the R-AdV. Intrarectal administration of R-AdVs expressing either VP4Δ::VP7 or VP4Δ::VP7::FljB in BALB/c mice resulted in HRV-specific mixed Th1/Th2 immune responses. The HRV-specific antibody response elicited with the use of R-AdV expressing VP4Δ::VP7::FljB was higher than that with R-AdV expressing VP4Δ::VP7. The results also show that the replication capability of R-AdVs contributed to enhance the HRV-specific immune response as compared with that obtained with non-replicative AdVs. This work lays the foundation for using the R-AdV system and FljB-adjuvanted formulation to elicit a mucosal immune response specific to HRV.

Mapping of the interaction domains of the Crimean-Congo hemorrhagic fever virus nucleocapsid protein

Crimean-Congo hemorrhagic fever virus (CCHFV) is a member of the genus Nairovirus of the family Bunyaviridae, that can cause severe haemorrhagic fever in humans, with mortality rates above 30  %. CCHFV is the most widespread of the tick-borne human viruses and it is endemic in areas of central Asia, the Middle East, Africa and southern Europe. Its viral genome consists of three negative-sense RNA segments. The large segment (L) encodes a viral RNA-dependent RNA polymerase (L protein), the small segment (S) encodes the nucleocapsid protein (N protein) and the medium segment (M) encodes the envelope proteins. The N protein of bunyaviruses binds genomic RNA, forming the viral ribonucleoprotein (RNP) complex. The L protein interacts with these RNP structures, allowing the initiation of viral replication. The N protein also interacts with actin, although the regions and specific residues involved in these interactions have not yet been described. Here, by means of immunoprecipitation and immunofluorescence assays, we identified the regions within the CCHFV N protein implicated in homo-oligomerization and actin binding. We describe the interaction of the N protein with the CCHFV L protein, and identify the N- and C-terminal regions within the L protein that might be necessary for the formation of these N-L protein complexes. These results may guide the development of potent inhibitors of these complexes that could potentially block CCHFV replication.

The dichotomy of pathogens and allergens in vaccination approaches

Traditional prophylactic vaccination to prevent illness is the primary objective of many research activities worldwide. The golden age of vaccination began with an approach called variolation in ancient China and the evolution of vaccines still continues today with modern developments such as the production of Gardasil(TM) against HPV and cervical cancer. The historical aspect of how different forms of vaccination have changed the face of medicine and communities is important as it dictates our future approaches on both a local and global scale. From the eradication of smallpox to the use of an experimental vaccine to save a species, this review will explore these successes in infectious disease vaccination and also discuss a few significant failures which have hampered our efforts to eradicate certain diseases. The second part of the review will explore designing a prophylactic vaccine for the growing global health concern that is allergy. Allergies are an emerging global health burden. Of particular concern is the rise of food allergies in developed countries where 1 in 10 children is currently affected. The formation of an allergic response results from the recognition of a foreign component by our immune system that is usually encountered on a regular basis. This may be a dust-mite or a prawn but this inappropriate immune response can result in a life-time of food avoidance and lifestyle restrictions. These foreign components are very similar to antigens derived from infectious pathogens. The question arises: should the allergy community be focussing on protective measures rather than ongoing therapeutic interventions to deal with these chronic inflammatory conditions? We will explore the difficulties and benefits of prophylactic vaccination against various allergens by means of genetic technology that will dictate how vaccination against allergens could be utilized in the near future.

Concordance of effects of medical interventions on hospital admission and readmission rates with effects on mortality

BACKGROUND

Many clinical trials examine a composite outcome of admission to hospital and death, or infer a relationship between hospital admission and survival benefit. This assumes concordance of the outcomes "hospital admission" and "death." However, whether the effects of a treatment on hospital admissions and readmissions correlate to its effect on serious outcomes such as death is unknown. We aimed to assess the correlation and concordance of effects of medical interventions on admission rates and mortality.

METHODS

We searched the Cochrane Database of Systematic Reviews from its inception to January 2012 (issue 1, 2012) for systematic reviews of treatment comparisons that included meta-analyses for both admission and mortality outcomes. For each meta-analysis, we synthesized treatment effects on admissions and death, from respective randomized trials reporting those outcomes, using random-effects models. We then measured the concordance of directions of effect sizes and the correlation of summary estimates for the 2 outcomes.

RESULTS

We identified 61 meta-analyses including 398 trials reporting mortality and 182 trials reporting admission rates; 125 trials reported both outcomes. In 27.9% of comparisons, the point estimates of treatment effects for the 2 outcomes were in opposite directions; in 8.2% of trials, the 95% confidence intervals did not overlap. We found no significant correlation between effect sizes for admission and death (Pearson r = 0.07, p = 0.6). Our results were similar when we limited our analysis to trials reporting both outcomes.

INTERPRETATION

In this metaepidemiological study, admission and mortality outcomes did not correlate, and discordances occurred in about one-third of the treatment comparisons included in our analyses. Both outcomes convey useful information and should be reported separately, but extrapolating the benefits of admission to survival is unreliable and should be avoided.

Epidemiology and genetic diversity of rotavirus strains in children with acute gastroenteritis in Lahore, Pakistan

Pakistan harbors high disease burden of gastro-enteric infections with majority of these caused by rotavirus. Unfortunately, lack of proper surveillance programs and laboratory facilities have resulted in scarcity of available data on rotavirus associated disease burden and epidemiological information in the country. We investigated 1306 stool samples collected over two years (2008–2009) from hospitalized children under 5 years of age for the presence of rotavirus strains and its genotypic diversity in Lahore. The prevalence rate during 2008 and 2009 was found to be 34% (n = 447 out of 1306). No significant difference was found between different age groups positive for rotavirus (p>0.05). A subset of EIA positive samples was further screened for rotavirus RNA through RT-PCR and 44 (49.43%) samples, out of total 89 EIA positive samples, were found positive. G and P type prevalence was found as follows: G1P [4] = 3(6.81%); G1P [6] = 9(20.45%); G1P [8] = 1(2.27%); G2P [4] = 21(47.72%); G2P [8] = 1(2.27%); G9P [4] = 1(2.27%); G9P [6] = 1(2.27%) and G9P [8] = 7(15.90%). Phylogenetic analysis revealed that the VP7 and VP4 sequences clustered closely with the previously detected strains in the country as well as Belgian rotaviruses. Antigenic characterization was performed by analyzing major epitopes in the immunodominant VP7 and VP4 gene segments. Although the neutralization conferring motifs were found variable between the Pakistani strains and the two recommended vaccines strains (Rotarix™ and RotaTeq™), we validate the use of rotavirus vaccine in Pakistan based on the proven and recognized vaccine efficacy across the globe. Our findings constitute the first report on rotavirus’ genotype diversity, their phylogenetic relatedness and epidemiology during the pre-vaccination era in Lahore, Pakistan and support the immediate introduction of rotavirus vaccine in the routine immunization program of the country.

Promoting appropriate management of diarrhea: a systematic review of literature for advocacy and action: UNICEF-PHFI series on newborn and child health, India

BACKGROUND

Scaling up of evidence-based management and prevention of childhood diarrhea is a public health priority in India, and necessitates robust literature review, for advocacy and action.

OBJECTIVE

To identify, synthesize and summarize current evidence to guide scaling up of management of diarrhea among under-five children in India, and identify existing knowledge gaps.

METHODS

A set of questions pertaining to the management (prevention, treatment, and control) of childhood diarrhea was identified through a consultative process. A modified systematic review process developed a priori was used to identify, synthesize and summarize, research evidence and operational information, pertaining to the problem in India. Areas with limited or no evidence were identified as knowledge gaps.

RESULTS

Childhood diarrhea is a significant public health problem in India; the point (two weeks) prevalence is 9 to 20%. Diarrhea accounts for 14% of the total deaths in under-five children in India. Infants aged 6 to 24 months are at the highest risk of diarrhea. There is a lack of robust nation-wide data on etiology; rotavirus and diarrheogenic E.coli are the most common organisms identified. The current National Guidelines are sufficient for case-management of childhood diarrhea. Exclusive breastfeeding, handwashing and point of use water treatment are effective strategies for prevention of all-cause diarrhea; rotavirus vaccines are efficacious to prevent rotavirus specific diarrhea. ORS and zinc are the mainstay of management during an episode of childhood diarrhea but have low coverage in India due to policy and programmatic barriers, whereas indiscriminate use of antibiotics and other drugs is common. Zinc therapy given during diarrhea can be upscaled through existing infrastructure is introducing the training component and information, education and communication activities.

CONCLUSION

This systematic review summarizes current evidence on childhood diarrhea and provides evidence to inform child health programs in India.

Role of antidiarrhoeal drugs as adjunctive therapies for acute diarrhoea in children

Acute diarrhoea is a leading cause of child mortality in developing countries. Principal pathogens include Escherichia coli, rotaviruses, and noroviruses. 90% of diarrhoeal deaths are attributable to inadequate sanitation. Acute diarrhoea is the second leading cause of overall childhood mortality and accounts for 18% of deaths among children under five. In 2004 an estimated 1.5 million children died from diarrhoea, with 80% of deaths occurring before the age of two. Treatment goals are to prevent dehydration and nutritional damage and to reduce duration and severity of diarrhoeal episodes. The recommended therapeutic regimen is to provide oral rehydration solutions (ORS) and to continue feeding. Although ORS effectively mitigates dehydration, it has no effect on the duration, severity, or frequency of diarrhoeal episodes. Adjuvant therapy with micronutrients, probiotics, or antidiarrhoeal agents may thus be useful. The WHO recommends the use of zinc tablets in association with ORS. The ESPGHAN/ESPID treatment guidelines consider the use of racecadotril, diosmectite, or probiotics as possible adjunctive therapy to ORS. Only racecadotril and diosmectite reduce stool output, but no treatment has yet been shown to reduce hospitalisation rate or mortality. Appropriate management with validated treatments may help reduce the health and economic burden of acute diarrhoea in children worldwide.

Expression of human rotavirus chimeric fusion proteins from replicating but non disseminating adenovectors and elicitation of rotavirus-specific immune responses in mice

The aim of this study was to evaluate the usefulness of replicating but non disseminating adenovirus vectors (AdVs) as vaccine vector using human rotavirus (HRV) as a model pathogen. HRV VP7, VP4, or VP4Δ (N-terminal 336 amino acids of VP4) structural proteins as well as the VP4Δ::VP7 chimeric fusion protein were expressed in mammalian cells when delivered with the AdVs. A preliminary experiment demonstrated that VP4Δ was able to induce a HRV-specific IgG response in BALB/c mice inoculated intramuscularly with AdVs expressing the rotaviral protein. Moreover, an AdV-prime/plasmid DNA-boost regimen of vectors resulted in VP4Δ-specific antibody (Ab) titers ~4 times higher than those obtained from mice immunized with AdVs alone. Subsequently, the various HRV protein-encoding AdVs were compared using the AdV-prime/plasmid DNA-boost regimen. Higher IgG and IgA responses to HRV were obtained when VP4Δ::VP7 fusion protein was used as an immunogen as compared to VP7 or VP4 alone or to a mix of both proteins delivered independently by AdVs. A synergetic effect in terms of Ab was obtained with VP4Δ::VP7. In conclusion, this study demonstrated for the first time the suitability of using replicating but non disseminating AdVs as vaccine vector and the VP4Δ::VP7 fusion protein as an immunogen for vaccination against HRV.

Vaccines for preventing rotavirus diarrhoea: vaccines in use

BACKGROUND

Rotavirus results in more diarrhoea-related deaths in children less than five years of age than any other single agent in countries with high childhood mortality. It is also a common cause of diarrhoea-related hospital admissions in countries with low childhood mortality. Currently licensed rotavirus vaccines include a monovalent rotavirus vaccine (RV1; Rotarix, GlaxoSmithKline Biologicals) and a pentavalent rotavirus vaccine (RV5; RotaTeq, Merck & Co., Inc.). Lanzhou lamb rotavirus vaccine (LLR; Lanzhou Institute of Biomedical Products) is used in China only.

OBJECTIVES

To evaluate rotavirus vaccines approved for use (RV1, RV5, and LLR) for preventing rotavirus diarrhoea.

SEARCH METHODS

We searched MEDLINE (via PubMed) (1966 to May 2012), the Cochrane Infectious Diseases Group Specialized Register (10 May 2012), CENTRAL (published in The Cochrane Library 2012, Issue 5), EMBASE (1974 to 10 May 2012), LILACS (1982 to 10 May 2012), and BIOSIS (1926 to 10 May 2012). We also searched the ICTRP (10 May 2012), www.ClinicalTrials.gov (28 May 2012) and checked reference lists of identified studies.

SELECTION CRITERIA

We selected randomized controlled trials (RCTs) in children comparing rotavirus vaccines approved for use with placebo, no intervention, or another vaccine.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility, extracted data, and assessed risk of bias. We combined dichotomous data using the risk ratio (RR) and 95% confidence intervals (CI). We stratified the analysis by child mortality, and used GRADE to evaluate evidence quality.

MAIN RESULTS

Forty-one trials met the inclusion criteria and enrolled a total of 186,263 participants. Twenty-nine trials (101,671 participants) assessed RV1, and 12 trials (84,592 participants) evaluated RV5. We did not find any trials assessing LLR.RV1Children aged less than one year: In countries with low-mortality rates, RV1 prevents 86% of severe rotavirus diarrhoea cases (RR 0.14, 95% CI 0.07 to 0.26; 40,631 participants, six trials; high-quality evidence), and, based on one large multicentre trial in Latin America and Finland, probably prevents 40% of severe all-cause diarrhoea episodes (rate ratio 0.60, 95% CI 0.50 to 0.72; 17,867 participants, one trial; moderate-quality evidence). In countries with high-mortality rates, RV1 probably prevents 63% of severe rotavirus diarrhoea cases (RR 0.37, 95% CI 0.18 to 0.75; 5414 participants, two trials; moderate-quality evidence), and, based on one trial in Malawi and South Africa, 34% of severe all-cause diarrhoea cases (RR 0.66, 95% CI 0.44 to 0.98; 4939 participants, one trial; moderate-quality evidence).Children aged up to two years: In countries with low-mortality rates, RV1 prevents 85% of severe rotavirus diarrhoea cases (RR 0.15, 95% CI 0.12 to 0.20; 32,854 participants, eight trials; high-quality evidence), and probably 37% of severe all-cause diarrhoea episodes (rate ratio 0.63, 95% CI 0.56 to 0.71; 39,091 participants, two trials; moderate-quality evidence). In countries with high-mortality rates, based on one trial in Malawi and South Africa, RV1 probably prevents 42% of severe rotavirus diarrhoea cases (RR 0.58, 95% CI 0.42 to 0.79; 2764 participants, one trial; moderate-quality evidence), and 18% of severe all-cause diarrhoea cases (RR 0.82, 95% CI 0.71 to 0.95; 2764 participants, one trial; moderate-quality evidence).RV5Children aged less than one year: In countries with low-mortality rates, RV5 probably prevents 87% of severe rotavirus diarrhoea cases (RR 0.13, 95% CI 0.04 to 0.45; 2344 participants, three trials; moderate-quality evidence), and, based on one trial in Finland, may prevent 72% of severe all-cause diarrhoea cases (RR 0.28, 95% CI 0.16 to 0.48; 1029 participants, one trial; low-quality evidence). In countries with high-mortality rates, RV5 prevents 57% of severe rotavirus diarrhoea (RR 0.43, 95% CI 0.29 to 0.62; 5916 participants, two trials; high-quality evidence), but there was insufficient data to assess the effect on severe all-cause diarrhoea.Children aged up to two years: Four studies provided data for severe rotavirus and all-cause diarrhoea in countries with low-mortality rates. Three trials reported on severe rotavirus diarrhoea cases and found that RV5 probably prevents 82% (RR 0.18, 95% CI 0.07 to 0.50; 3190 participants, three trials; moderate-quality evidence), and another trial in Finland reported on severe all-cause diarrhoea cases and found that RV5 may prevent 96% (RR 0.04, 95% CI 0.00 to 0.70; 1029 participants, one trial; low-quality evidence). In high-mortality countries, RV5 prevents 41% of severe rotavirus diarrhoea cases (RR 0.59, 95% CI 0.43 to 0.82; 5885 participants, two trials; high-quality evidence), and 15% of severe all-cause diarrhoea cases (RR 0.85, 95% CI 0.75 to 0.98; 5977 participants, two trials; high-quality evidence).There was no evidence of a vaccine effect on mortality (181,009 participants, 34 trials; low-quality evidence), although the trials were not powered to detect an effect on this end point.Serious adverse events were reported in 4565 out of 99,438 children vaccinated with RV1 and in 1884 out of 78,226 children vaccinated with RV5. Fifty-eight cases of intussusception were reported in 97,246 children after RV1 vaccination, and 34 cases in 81,459 children after RV5 vaccination. No significant difference was found between children receiving RV1 or RV5 and placebo in the number of serious adverse events, and intussusception in particular.

AUTHORS' CONCLUSIONS

RV1 and RV5 prevent episodes of rotavirus diarrhoea. The vaccine efficacy is lower in high-mortality countries; however, due to the higher burden of disease, the absolute benefit is higher in these settings. No increased risk of serious adverse events including intussusception was detected, but post-introduction surveillance studies are required to detect rare events associated with vaccination.

Molecular characterization of rotavirus strains detected during a clinical trial of a human rotavirus vaccine in Blantyre, Malawi

The human, G1P[8] rotavirus vaccine (Rotarix™) significantly reduced severe rotavirus gastroenteritis episodes in a clinical trial in South Africa and Malawi, but vaccine efficacy was lower in Malawi (49.5%) than reported in South Africa (76.9%) and elsewhere. The aim of this study was to examine the molecular relationships of circulating wild-type rotaviruses detected during the clinical trial in Malawi to RIX4414 (the strain contained in Rotarix™) and to common human rotavirus strains. Of 88 rotavirus-positive, diarrhoeal stool specimens, 43 rotaviruses exhibited identifiable RNA migration patterns when examined by polyacrylamide gel electrophoresis. The genes encoding VP7, VP4, VP6 and NSP4 of 5 representative strains possessing genotypes G12P[6], G1P[8], G9P[8], and G8P[4] were sequenced. While their VP7 (G) and VP4 (P) genotype designations were confirmed, the VP6 (I) and NSP4 (E) genotypes were either I1E1 or I2E2, indicating that they were of human rotavirus origin. RNA-RNA hybridization using 21 culture-adapted strains showed that Malawian rotaviruses had a genomic RNA constellation common to either the Wa-like or the DS-1 like human rotaviruses. Overall, the Malawi strains appear similar in their genetic make-up to rotaviruses described in countries where vaccine efficacy is greater, suggesting that the lower efficacy in Malawi is unlikely to be explained by the diversity of circulating strains.

Efficacy of human rotavirus vaccine against severe gastroenteritis in Malawian children in the first two years of life: a randomized, double-blind, placebo controlled trial

Rotavirus gastroenteritis is a major cause of morbidity and mortality among African infants and young children. A phase III, placebo-controlled, multi-centre clinical trial of a live, oral G1P[8] human rotavirus vaccine (RIX4414) undertaken in Malawi and South Africa significantly reduced the incidence of severe rotavirus gastroenteritis in the first year of life. We now report on vaccine efficacy in the Malawi cohort of children who were followed into the second year of life. A total of 1773 healthy infants were enrolled in Blantyre, Malawi into three groups. Two groups received three doses of RIX4414 or placebo at age 6, 10, and 14 weeks and the third group received placebo at 6 weeks and RIX4414 at age 10 and 14 weeks. Subjects were followed by weekly home visits for episodes of gastroenteritis until 1 year of age, and were then re-consented for further follow-up to 18-24 months of age. Severity of gastroenteritis episodes was graded according to the Vesikari scoring system. Seroconversion for anti-rotavirus IgA was determined on a subset of children by using ELISA on pre- and post-vaccine blood samples. Rotavirus VP7 (G) and VP4 (P) genotypes were determined by RT-PCR. A total of 70/1030 (6.8%, 95% CI 5.3-8.5) subjects in the pooled (2 dose plus 3 dose) RIX4414 group compared with 53/483 (11.0%, 8.3-14.1) subjects in the placebo group developed severe rotavirus gastroenteritis in the entire follow-up period (vaccine efficacy 38.1% (9.8-57.3)). The point estimate of efficacy in the second year of life (17.6%; -59.2 to 56.0) was lower than in the first year of life (49.4%; 19.2-68.3). There were non-significant trends towards a higher efficacy in the second year of life among children who received the three-dose schedule compared with the two-dose schedule, and a higher anti-rotavirus IgA seroresponse rate in the three-dose RIX4414 group. Rotavirus strains detected included genotype G12 (31%); G9 (23%); and G8 (18%); only 18% of strains belonged to the G1P[8] genotype. While the optimal dosing schedule of RIX4414 in African infants requires further investigation, vaccination with RIX4414 significantly reduced the incidence of severe gastroenteritis caused by diverse rotavirus strains in an impoverished African population with high rotavirus disease burden in the first two years of life.

Vaccines for preventing rotavirus diarrhoea: vaccines in use

BACKGROUND

Rotavirus results in more diarrhoea-related deaths in children less than five years of age than any other single agent in low- and middle-income countries. It is also a common cause of diarrhoea-related hospital admissions in high-income countries. The World Health Organization (WHO) recommends that all children should be vaccinated with a monovalent rotavirus vaccine (RV1; Rotarix, GlaxoSmithKline Biologicals) or a pentavalent rotavirus vaccine (RV5; RotaTeq, Merck & Co., Inc.), with a stronger recommendation for countries where deaths due to diarrhoea comprise more than 10% of all deaths. Lanzhou lamb rotavirus vaccine (LLR; Lanzhou Institute of Biomedical Products) is used in China only.

OBJECTIVES

To evaluate rotavirus vaccines approved for use (RV1, RV5, and LLR) for preventing rotavirus diarrhoea. Secondary objectives were to evaluate the efficacy of rotavirus vaccines on all-cause diarrhoea, hospital admission, death, and safety profiles.

SEARCH METHODS

For this update, we searched MEDLINE (via PubMed) in October 2011, and in June 2011 we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (published in The Cochrane Library 2011, Issue 2), , EMBASE, LILACS, and BIOSIS. We also searched the ICTRP (28 June 2011) and checked reference lists of identified studies.

SELECTION CRITERIA

We selected randomized controlled trials in children comparing rotavirus vaccines approved for use with placebo, no intervention, or another vaccine.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility, extracted data, and assessed risk of bias. They combined dichotomous data using the risk ratio (RR) and 95% confidence intervals (CI) and used GRADE to evaluate evidence quality, which was reflected as follows: high quality ("vaccine prevents..."); moderate quality ("vaccine probably prevents..."); or low quality ("vaccine may prevent...").

MAIN RESULTS

Forty-three trials, including nine new trials for this update, met the inclusion criteria and enrolled 190,551 participants. Thirty-one trials assessed RV1, and 12 trials evaluated RV5. We did not find any trials assessing LLR.In children aged less than one year, RV1, compared to placebo, probably prevents 70% of all cases of rotavirus diarrhoea (RR 0.30, 95% CI 0.18 to 0.50; seven trials, 12,130 participants; moderate-quality evidence), and 80% of severe rotavirus diarrhoea cases (RR 0.20, 95% CI 0.11 to 0.35; seven trials, 35,004 participants; moderate-quality evidence). Similarly, RV5 prevents 73% of all rotavirus diarrhoea cases (RR 0.27, 95% CI 0.22 to 0.33; four trials, 7614 participants; high-quality evidence), and 77% of severe rotavirus diarrhoea cases (RR 0.23, 95% CI 0.08 to 0.71; three trials, 6953 participants; high-quality evidence). Both vaccines prevent over 80% of rotavirus diarrhoea cases that require hospitalization. For all-cause diarrhoea, based on two multi-centred trials from South Africa, Malawi, and Europe, RV1 may reduce severe cases by 42% (RR 0.58, 95% CI 0.40 to 0.84; two trials, 8291 participants; low--quality evidence). Also, based on one trial from Finland, RV5 may reduce severe cases by 72% (RR 0.28, 95% CI 0.16 to 0.48; one trial, 1029 participants; low-quality evidence).During the second year of life, compared to placebo, RV1 probably prevents 70% of all cases of rotavirus diarrhoea of any severity (RR 0.30, 95% CI 0.21 to 0.43; six trials, 8041 participants; moderate-quality evidence), and 84% of severe rotavirus diarrhoea cases (RR 0.16, 95% CI 0.12 to 0.21; eight trials, 32,854 participants; moderate-quality evidence). RV5 prevents 49% of all rotavirus diarrhoea cases of any severity (RR 0.51, 95% CI 0.36 to 0.72; four trials, 9784 participants; high-quality evidence), and 56% of severe rotavirus diarrhoea cases (RR 0.44, 95% CI 0.22 to 0.88; four trials, 9783 participants; high-quality evidence). For all-cause diarrhoea, RV1 probably reduces severe cases by 51% (RR 0.49, 95% CI 0.40 to 0.60; two trials, 6269 participants; moderate-quality evidence), and RV5 showed no difference with placebo (three trials, 8533 participants).Reported serious adverse events (including intussusception) after vaccination were measured in 95,178 children for RV1 and 77,480 for RV5, with no difference between the vaccines.

AUTHORS' CONCLUSIONS

RV1 and RV5 vaccines are effective in preventing rotavirus diarrhoea. These data support the WHO's global vaccine recommendation. The potential for reduced vaccine efficacy in low-income countries needs to be investigated. No increased risk of intussusception was detected, but surveillance monitoring studies are probably advisable in countries introducing the vaccine nationally.

Acute infectious diarrhea

Infectious diarrhea is both a local and a global concern. Illnesses can range from mild inconveniences to life-threatening epidemics. Although diarrhea can be caused by a vast array of pathogens, the cornerstone of prevention is provision of a safe food and water supply, application of basic hygiene principles, and the development and administration of vaccines. The cornerstone of treatment is rehydration. Selection of specific antimicrobial therapy should be based on disease presentation and epidemiologic factors.

Genetic analyses reveal differences in the VP7 and VP4 antigenic epitopes between human rotaviruses circulating in Belgium and rotaviruses in Rotarix and RotaTeq

Two live-attenuated rotavirus group A (RVA) vaccines, Rotarix (G1P[8]) and RotaTeq (G1-G4, P[8]), have been successfully introduced in many countries worldwide, including Belgium. The parental RVA strains used to generate the vaccines were isolated more than 20 years ago in France (G4 parental strain in RotaTeq) and the United States (all other parental strains). At present, little is known about the relationship between currently circulating human RVAs and the vaccine strains. In this study, we determined sequences for the VP7 and VP4 outer capsid proteins of representative G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], and G12P[8] RVAs circulating in Belgium during 2007 to 2009. The analyses showed that multiple amino acid differences existed between the VP7 and VP4 antigenic epitopes of the vaccine viruses and the Belgian isolates, regardless of their G and P genotypes. However, the highest variability was observed among the circulating G1P[8] RVA strains and the G1 and P[8] components of both RVA vaccines. In particular, RVA strains of the P[8] lineage 4 (OP354-like) showed a significant number of amino acid differences with the P[8] VP4 of both vaccines. In addition, the circulating Belgian G3 RVA strains were found to possibly possess an extra N-linked glycosylation site compared to the G3 RVA vaccine strain of RotaTeq. These results indicate that the antigenic epitopes of RVA strains contained in the vaccines differ substantially from those of the currently circulating RVA strains in Belgium. Over time, these differences might result in selection for strains that escape the RVA neutralizing-antibody pressure induced by vaccines.

Acute diarrhoea in a community cohort of children who received an oral rotavirus vaccine in Northeast Brazil

Rotavirus is an important cause of childhood diarrhoea. A monovalent rotavirus vaccine (Rotarix®) was introduced into the Immunization Program of Brazil in 2006. In this study, we describe the incidence and burden of disease of rotavirus diarrhoea in two cohorts of children (vaccinated and unvaccinated). We followed two groups of 250 children under one year old, who were enrolled in December 2006 from a low-income residential area in Northeast Brazil. The children were monitored every two weeks for two years. Stool samples from children with diarrhoea were examined for the presence of rotavirus. Rotaviruses were genotyped using real time-polymerase chain reaction. The mean numbers of all-cause diarrhoea episodes/child (adjusted for age) in the first year were 0.87 and 0.84, in vaccinated and unvaccinated children, respectively. During the second year, the number of episodes/child decreased to 0.52 and 0.42. Only 16 (4.9%) of 330 stool samples were rotavirus-positive (10 vaccinated and 6 unvaccinated children) and only P[4]G2 rotaviruses were identified. All-cause diarrhoea episodes were more severe in unvaccinated children in the first year of age (p < 0.05), while vaccinated children had more severe episodes 18 months after vaccination. Rotavirus diarrhoea incidence was very low in both groups.