Efficacy of human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in European infants: randomised, double-blind controlled study

Diagnosis of viral gastroenteritis in children: interpretation of real-time PCR results and relation to clinical symptoms

Molecular methods such as real-time polymerase chain reaction (PCR) are rapidly replacing traditional tests to detect fecal viral pathogens in childhood diarrhea. This technique has now increased the analytical sensitivity so drastically that positive results are found in asymptomatic children, leading to complex interpretation of real-time PCR results and difficult distinction between asymptomatic shedding and etiological cause of disease. We performed a review of the literature including pediatric studies using real-time PCR and a minimal inclusion period of one year to exclude bias by seasonality. We searched for studies on rotavirus, norovirus, adenovirus, astrovirus, and sapovirus, known to be the most common viruses to cause gastroenteritis in the pediatric population. For these viruses, we summarized the detection rates in hospitalized and community-based children with clinical symptoms of gastroenteritis, as well as subjects with asymptomatic viral shedding. Moreover, insight is given into the different viral sero- and genotypes causing pediatric gastroenteritis. We also discuss the scoring systems for severity of disease and their clinical value. A few published proposals have been made to improve the clinical interpretation of real-time PCR results, which we recapitulate and discuss in this review. We propose using the semi-quantitative measure of real-time PCR, as a surrogate for viral load, in relation to the severity score to distinguish asymptomatic viral shedding from clinically relevant disease. Overall, this review provides a better understanding of the scope of childhood gastroenteritis, discusses a method to enhance the interpretation of real-time PCR results, and proposes conditions for future research to enhance clinical implementation.

Co-expression of anti-rotavirus proteins (llama VHH antibody fragments) in Lactobacillus: development and functionality of vectors containing two expression cassettes in tandem

Rotavirus is an important pediatric pathogen, causing severe diarrhea and being associated with a high mortality rate causing approximately 500 000 deaths annually worldwide. Even though some vaccines are currently available, their efficacy is lower in the developing world, as compared to developed countries. Therefore, alternative or complementary treatment options are needed in the developing countries where the disease burden is the largest. The effect of Lactobacillus in promoting health and its use as a vehicle for delivery of protein and antibody fragments was previously shown. In this study, we have developed co-expression vectors enabling Lactobacillus paracasei BL23 to produce two VHH fragments against rotavirus (referred to as anti-rotavirus proteins 1 and 3, ARP1 and ARP3) as secreted and/or surface displayed products. ARP1 and ARP3 fragments were successfully co-expressed as shown by Western blot and flow cytometry. In addition, engineered Lactobacillus produced VHH antibody fragments were shown to bind to a broad range of rotavirus serotypes (including the human rotavirus strains 69M, Va70, F45, DS1, Wa and ST3 and simian rotavirus strains including RRV and SA11), by flow cytometry and ELISA. Hereby, we have demonstrated for the first time that when RRV was captured by one VHH displayed on the surface of co-expressor Lactobacillus, targeting other epitope was possible with another VHH secreted from the same bacterium. Therefore, Lactobacillus producing two VHH antibody fragments may potentially serve as treatment against rotavirus with a reduced risk of development of escape mutants. This co-expression and delivery platform can also be used for delivery of VHH fragments against a variety of mucosal pathogens or production of other therapeutic molecules.

Rotavirus vaccines: current status and future considerations

Rotavirus is the leading cause of severe diarrhea among children<5 years worldwide. Currently licensed rotavirus vaccines have been efficacious and effective, with many countries reporting substantial declines in diarrheal and rotavirus-specific morbidity and mortality. However, the full public health impact of these vaccines has not been realized. Most countries, including those with the highest disease burden, have not yet introduced rotavirus vaccines into their national immunization programs. Research activities that may help inform vaccine introduction decisions include (1) establishing effectiveness, impact, and safety for rotavirus vaccines in low-income settings; (2) identifying potential strategies to improve performance of oral rotavirus vaccines in developing countries, such as zinc supplementation; and (3) pursuing alternate approaches to oral vaccines, such as parenteral immunization. Policy- and program-level barriers, such as financial implications of new vaccine introductions, should be addressed to ensure that countries are able to make informed decisions regarding rotavirus vaccine introduction.

Adjuvant potential of low dose all-trans retinoic acid during oral typhoid vaccination in Zambian men

There is an urgent need to identify ways of enhancing the mucosal immune response to oral vaccines. Rotavirus vaccine protection is much lower in Africa and Asia than in industrialized countries, and no oral vaccine has efficacy approaching the best systemic vaccines. All-trans retinoic acid (ATRA) up-regulates expression of α4β7 integrin and CCR9 on lymphocytes in laboratory animals, increasing their gut tropism. The aim of this study was to establish the feasibility of using ATRA as an oral adjuvant for oral typhoid vaccination. In order to establish that standard doses of oral ATRA can achieve serum concentrations greater than 10 nmol/l, we measured ATRA, 9-cis and 13-cis retinoic acid in serum of 14 male volunteers before and 3 h after 10 mg ATRA. We then evaluated the effect of 10 mg ATRA given 1 h before, and for 7 days following, oral typhoid vaccine in eight men, and in 24 men given various control interventions. We measured immunoglobulin (Ig)A directed against lipopolysaccharide (LPS)and protein preparations of vaccine antigens in whole gut lavage fluid (WGLF) and both IgA and IgG in serum, 1 day prior to vaccination and on day 14. Median [interquartile range (IQR)] C(max) was 26·2 (11·7-39·5) nmol/l, with no evidence of cumulation over 8 days. No adverse events were observed. Specific IgA responses to LPS (P = 0·02) and protein (P = 0·04) were enhanced in WGLF, but no effect was seen on IgA or IgG in serum. ATRA was well absorbed, well tolerated and may be a promising candidate oral adjuvant.

Effectiveness of 2 rotavirus vaccines against rotavirus disease in Taiwanese infants

BACKGROUND

Two rotavirus (RV) vaccines (Rotarix and RotaTeq) are available on the private market in Taiwan, but are not recommended for routine use. We examined RV vaccine effectiveness (VE) against severe RV acute gastroenteritis (AGE) among Taiwanese infants to inform policymakers on the potential benefits of national RV vaccine introduction.

METHODS

From May 2009 to April 2011, a case-control assessment of VE against severe RV AGE was conducted at 3 hospital-based surveillance sites in Taiwan. Case-patients included children aged 8-35 months, hospitalized with laboratory-confirmed RV AGE. Controls included children age-matched within 1 month of age of the case-patient, hospitalized with RV-negative AGE or seen for non-AGE illnesses at the same hospitals. Vaccination history was confirmed through vaccination card or hospital record review. VE was calculated as (1--odds ratio of vaccination) × 100%.

RESULTS

We enrolled 184 case-patients with RV AGE, 904 RV-negative AGE and 909 non-AGE controls. Two-dose Rotarix series VE against RV gastroenteritis hospitalization was 90.4% [95% confidence interval (CI): 70.3%, 98.1%) and 92.5% (95% CI: 77.1%, 98.5%) with RV-negative AGE and non-AGE controls, respectively. Three-dose RotaTeq series VE was 96.8% (95% CI: 82.3%, 100%) and 97.1% (95% CI: 84%, 100%) with RV-negative AGE and non-AGE controls, respectively.

CONCLUSIONS

Both vaccines provided excellent protection against severe RV AGE hospitalization. Addition of RV vaccination into Taiwan's National Immunization Program could substantially decrease AGE hospitalizations among children <3 years. Our findings should help inform policymakers in Taiwan and other similar Asian countries when deciding whether to include RV vaccination into their national immunization programs.

Temporal trends in diarrhea-related hospitalizations and deaths in children under age 5 before and after the introduction of the rotavirus vaccine in four Latin American countries

INTRODUCTION

Rotavirus infection mainly affects children under 5 years of age and causes 453,000 deaths annually throughout the world. Several countries in Latin America have introduced the rotavirus vaccine and the majority have epidemiological data to measure impact following vaccine introduction.

OBJECTIVE

To assess the impact of rotavirus immunization on the number of all-cause diarrhea-related deaths and hospitalizations in children under 1 and 5 years of age in Bolivia, El Salvador, Honduras and Venezuela.

METHODS

Interrupted time-series analyzed with the integral method and the projection method to evaluate the pre and post-vaccine introduction trend in diarrheal disease compared to Argentina as the control country. The analysis period was from 2002 to 2010, including 2 to 4 post-vaccine years depending on the country. Information sources included records from PAHO, the Ministry of Health, public hospitals, social security, the private health system, the Expanded Programme on Immunization and UNPop 2008.

RESULTS

Over the period studied, reductions were observed in trends of diarrhea-related deaths and hospitalizations in children under five. In diarrhea-related deaths, under the integral method, the range of reduction was between 15.7% (13.5-17.9) and 56.8% (56.0-57.5) while with the projection method was between 19.9% (4.9-34.8) and 63.7%(56.1-71.4). In diarrhea-related hospitalizations, under the integral method was 5.6% (4.1-6.7) and 17.9% (16.7-19.1)) while with the projection method was between 5.1%(1.7-8.7) and 11.1% (5.8-16.3) CONCLUSIONS: A decrease was observed in the number of diarrhea related deaths and hospitalizations in all countries under study following introduction of the rotavirus vaccine as opposed to the control country. The impact on reduction of deaths was greater than hospitalization.

Effectiveness and impact of rotavirus vaccines in the United States - 2006-2012

Prior to the introduction of rotavirus vaccines in 2006, rotavirus was the leading cause of severe gastroenteritis among US children <5 years of age. In the first 7 years of vaccine use, both recommended rotavirus vaccines (RotaTeq [RV5] and Rotarix [RV1]) have been shown to be highly effective in preventing outcomes of severe disease in US children in a variety of settings. In addition, substantial decreases in severe diarrheal disease in US children, exceeding the level expected based on vaccine coverage, as well as the extension of benefits to older age groups ineligible for vaccination have demonstrated both the direct and indirect impacts of vaccination in the USA.

Hospital-based surveillance for rotavirus gastroenteritis in children younger than 5 years of age in Ethiopia: 2007-2012

BACKGROUND

Rotavirus surveillance was initiated in Ethiopia to estimate the burden of rotavirus gastroenteritis in children <5 years of age, to generate data to assist the policy-making process for new vaccine introduction and to monitor impact of vaccination on disease burden after introduction.

METHODS

Sentinel surveillance was conducted at 3 hospitals in Addis Ababa, Ethiopia using a standardized WHO surveillance protocol from August 2007 to March 2012. Children <5 years of age, hospitalized for the primary reason of treatment for acute gastroenteritis, were enrolled, stool samples were collected and tested for group A rotavirus using an enzyme immunoassay. Confirmed positive specimens were further characterized by rotavirus genotyping.

RESULTS

A total of 1841 children were enrolled and 21% were rotavirus positive. Children 6-12 months of age had the highest proportion of rotavirus (36%) followed by children <6 months of age (23%). There was no significant difference between sexes. Significant differences in clinical characteristics, such as vomiting, vomiting episodes, cases with vomiting and diarrhea among rotavirus positive cases, were observed. Rotavirus circulated year round with peak prevalence from October through January. The most prevalent detected genotypes were G1P[8] (20%), G12P[8] (17%) and G3P[6] (15%), respectively.

CONCLUSIONS

Rotavirus infection is common in Ethiopian children. A safe and effective intervention against the infection is needed to prevent severity of the disease. Rotavirus vaccine introduction is planned before the end of 2013. The established surveillance system and the data generated can be used to monitor the impact of rotavirus vaccination program on severe disease.

Rotavirus G and P types circulating in the eastern region of Kenya: predominance of G9 and emergence of G12 genotypes

BACKGROUND

The World Health Organization has recommended that rotavirus (RV) vaccines be included in all national immunization programs as part of a strategy to control RV-associated diarrheal diseases. Hospital-based surveillance of RV infection is therefore crucial in monitoring the impact pre- and post-vaccine introduction and also to document changes in genotype distribution. This study sought to determine the RV genotypes circulating in the eastern region of Kenya before introduction of the RV vaccine.

METHODS

During September 2009 to August 2011, 500 stool samples were collected from children <5 years of age admitted for acute diarrhea in hospitals in the eastern region of Kenya and analyzed for the presence of group A RV using an enzyme immunoassay. G and P genotypes were determined using hemi-nested reverse transcriptase polymerase chain reaction.

RESULTS

One hundred and eighty nine out of 500 (38%) samples analyzed were positive for rotavirus. The following G types were detected: G9 (50.9%), G1 (26.8%), G8 (12.1%), G12 (3.1%), G2 (0.6%), mixed G (1.3%) and 5.1% were G nontypeable. P types detected included: P[8] (63.7%), P[4] (12.1%), P[6] (4.5%), mixed P (7.6%) and 12.1% were P nontypeable. The most dominant strain was G9P[8] (35%), followed by G1P[8] (26.8%), G8P[4] (9.6%), G12P[6] (2.5%), G9P[6] (1.9%), G9P[4] (1.3%), G8P[8] (1.3%), and G2P[4] (0.6%).

CONCLUSIONS

The present study demonstrates the recurring changing genotypes of RV circulating in Kenya, with genotypes G9, G1 and G8 being the dominant strains circulating in the eastern region of Kenya between 2009 and 2011. Additionally, G12 genotype was detected for the first time in Kenya.

Real-time RT-PCR assays to differentiate wild-type group A rotavirus strains from Rotarix(®) and RotaTeq(®) vaccine strains in stool samples

Group A rotaviruses (RVA) are the leading cause of severe diarrhea in young children worldwide. Two live-attenuated RVA vaccines, Rotarix(®) and RotaTeq(®) are recommended by World Health Organization (WHO) for routine immunization of all infants. Rotarix(®) and RotaTeq(®) vaccines have substantially reduced RVA associated mortality but occasionally have been associated with acute gastroenteritis (AGE) cases identified in vaccinees and their contacts. High-throughput assays are needed to monitor the prevalence of vaccine strains in AGE cases and emergence of new vaccine-derived strains following RVA vaccine introduction. In this study, we have developed quantitative real-time RT-PCR (qRT-PCR) assays for detection of Rotarix(®) and RotaTeq(®) vaccine components in stool samples. Real-time RT-PCR assays were designed for vaccine specific targets in the genomes of Rotarix(®) (NSP2, VP4) and RotaTeq(®) (VP6, VP3-WC3, VP3-human) and validated on sequence confirmed stool samples containing vaccine strains, wild-type RVA strains, and RVA-negative stools. For quantification, standard curves were generated using dsRNA transcripts derived from RVA gene segments. Rotarix(®) NSP2 and VP4 qRT-PCR assays exhibited 92-100% sensitivity, 99-100% specificity, 94-105% efficiency, and a limit of detection of 2-3 copies per reaction. RotaTeq(®) VP6, VP3-WC3, and VP3-human qRT-PCR assays displayed 100% sensitivity, 94-100% specificity, 91-102% efficiency and limits of detection of 1 copy, 2 copies, and 140 copies, respectively. These assays permit rapid identification of Rotarix(®) and RotaTeq(®) vaccine components in stool samples from clinical and surveillance studies and will be helpful in determining the frequency of vaccine strain-associated AGE.

Rotavirus vaccination in Brazil: effectiveness and health impact seven years post-introduction

Before vaccine introduction in Brazil, rotavirus caused approximately 650,000 outpatient visits, 92,000 hospitalizations and 850 deaths annually among children aged <5 years. Brazil was one of the first countries to introduce rotavirus vaccination into the National Immunisation Program (NIP), in 2006, but estimated coverage (87.1%) for 2011 remained lower if compared with other routine immunizations (95%). Case-control studies reached effectiveness rates as high as 85%. Observational studies showed a significant reduction in gastroenteritis-related hospitalizations and deaths among children aged <1 year, at rates as high as 48 and 54%, respectively. There was a significant increase in the relative prevalence of G2P[4] genotype after vaccine introduction, reaching 100% of strains in some settings. A small increase in intussusception incidence was seen within 1 week following the second vaccine dose, but benefits far outweigh any potential risk. This article provides an in-depth review of postlicensure studies conducted in Brazil 7-year postintroduction.

Impact and effectiveness of RotaTeq® vaccine based on 3 years of surveillance following introduction of a rotavirus immunization program in Finland

BACKGROUND

Finland introduced universal rotavirus (RV) vaccination in September 2009, with exclusive use of the pentavalent human-bovine reassortant RV vaccine RotaTeq® and following a vaccination schedule at 2, 3 and 5 months of age. This study monitored the impact of RV vaccination on hospitalizations due to RV acute gastroenteritis (RVGE). The results following the first 3 RV seasons after implementation of universal RV vaccination are presented.

METHODS

Prospective hospital-based surveillance identified children with acute gastroenteritis admitted to 2 University Hospitals (Tampere and Oulu, Finland), from December 2009 to August 2012. The surveillance covered a population of approximately 173,000 children from the 2 hospitals' catchment areas. Stool samples were taken and analyzed centrally for RV by enzyme-linked immunosorbent assay, with genotyping by reverse transcription polymerase chain reaction. International Classification of Diseases discharge codes were collected retrospectively pre- and postvaccination.

RESULTS

During the 3-year prospective surveillance, 127 RVGE episodes were identified. Of these, 117 were in unvaccinated children and 6 were in fully vaccinated children (RotaTeq, n = 3; Rotarix, n = 3). The vaccine effectiveness against hospitalized RVGE for fully vaccinated children was 92.1% [95% confidence interval (CI): 50.0-98.7] among children eligible for the National Immunization Program. When analyzing retrospectively the Tampere and Oulu hospital databases for all children aged <16 years, hospitalizations for RVGE had decreased by 78% in the postvaccination period (2009-2012) compared with the prevaccination data (2001-2006).

CONCLUSIONS

Severe RVGE requiring hospitalization was virtually eliminated in vaccine-eligible children in the 3 years following implementation of universal RotaTeq vaccination in Finland.

Prevalence of rotavirus genotypes in South Korea in 1989-2009: implications for a nationwide rotavirus vaccine program

The epidemiology of human group A rotavirus was analyzed by examining genotypic data acquired from 1989 to 2009 in South Korea. This information was derived from all the available published articles on rotavirus studies in South Korea, retrieved from both the PubMed and KoreaMed databases. Four common G types (G1, G2, G3, and G4) and three common P types (P[8], P[4], and P[6]) accounted for approximately 93% and 99% of the rotavirus reports, respectively. The G9 type was frequently detected after 2000, and because of this prevalence, it is considered to be the fifth most important G type rotavirus after the G1.G4 genotypes. Less common G types of the virus such as G12, G11, and G10 were detected in some geographic settings, and it is important to consider the context of these subtypes and their epidemiological significance. The P[9] virus genotype was observed in the study and has been discussed in many other studies; however, the P[3], P[10] and P[25] genotypes were rarely detected in the epidemiological research. In general, the distributions of the G and P genotypes showed temporal and geographical fluctuations, and a nationwide rotavirus vaccine program that targeted these genotypes demonstrated effectiveness in protecting against the circulating rotavirus strains. However, further analysis is needed to determine the true long-term effectiveness of these vaccines; the analysis should also consider the unexpected effects of vaccinations, such as vaccine-induced diseases, herd immunity, and changes in host susceptibilities.

Will vaccination against rotavirus infection with RIX4414 be cost-saving in Germany?

BACKGROUND

Rotavirus gastroenteritis (RVGE) is a frequent disease in young children. The recommended German paediatric immunisation schedule does not currently include rotavirus vaccination. A lack of economic data on the impact of routine vaccination is stated as one of the reasons. As a result, the current coverage rate is low, around 26%. This study investigated whether rotavirus vaccination using the two-dose rotavirus vaccine RIX4414 (Rotarix®, GlaxoSmithKline Vaccines) would be a cost-saving intervention from the perspective of the statutory health insurance (SHI) in Germany.

OBJECTIVE

The objective of the study was to analyse health outcomes (number of RVGE cases and hospitalisations prevented) and the associated cost to the SHI when comparing 100% rotavirus vaccination with no vaccination in Germany.

METHODS

A Markov cohort model simulated the number of RVGE events and related costs in a German birth cohort over the first 60 months of life with current disease management. The model compared an unvaccinated cohort with a fully vaccinated cohort. Vaccine efficacy data from international clinical trials were combined with German-specific epidemiological and cost data. Results were tested using extensive sensitivity analyses.

RESULTS

Full vaccination of a birth cohort against rotavirus disease would be expected to prevent 82% of RVGE cases, reducing RVGE frequency from 28 to 5 events per 100 children in the birth cohort up to age 5 years. The estimated cost reduction with vaccination for that period is predicted to be €9.2 million with 100% coverage (€6.9 million with 75% coverage), mainly due to reductions in SHI reimbursement for productivity losses, hospital stays and visits to office-based physicians due to the vaccine's efficacy against severe disease.

CONCLUSIONS

Routine rotavirus vaccination in Germany would reduce the number of hospitalised and outpatient cases. The associated investment could be fully offset by costs avoided in hospital stays, physician visits and SHI reimbursement of productivity losses. Sensitivity analysis indicated that vaccination would be cost-saving in 95% of simulations. Incremental cost was observed only under extreme conditions, especially when the time spent at home due to rotavirus disease was low or when vaccine efficacy against severe disease was heavily decreased.

Association of serum anti-rotavirus immunoglobulin A antibody seropositivity and protection against severe rotavirus gastroenteritis: analysis of clinical trials of human rotavirus vaccine

Clinical trials of the human rotavirus vaccine Rotarix™ (RV1) have demonstrated significant reductions in severe rotavirus gastroenteritis (RVGE) in children worldwide. However, no correlate of vaccine efficacy (VE) has yet been established. This paper presents 2 analyses which aimed to investigate whether serum anti-RV IgA measured by ELISA 1 or 2 mo post-vaccination can serve as a correlate of efficacy against RVGE: (1) In a large Phase III efficacy trial (Rota-037), the Prentice criteria for surrogate endpoints was applied to anti-RV IgA seropositivity 1 mo post-vaccination. These criteria determine whether a significant vaccine group effect can be predicted from the surrogate, namely seropositivity (anti-RV IgA concentration >20 U/mL); (2) Among other GSK-sponsored RV1 VE studies, 8 studies which assessed immunogenicity at 1 or 2 mo post-vaccination in all or a sub-cohort of enrolled subjects and had at least 10 RVGE episodes were included in a meta-analysis to measure the regression between clinical VE and VE predicted from immunogenicity (VE1). In Rota-037, anti-RV IgA seropositivity post-vaccination was associated with a lower incidence of any or severe RVGE, however, the proportion of vaccine group effect explained by seropositivity was only 43.6% and 32.7% respectively. This low proportion was due to the vaccine group effect observed in seronegative subjects. In the meta-analysis, the slope of the regression between clinical VE and VE1 was statistically significant. These two independent analyses support the hypothesis that post-vaccination anti-RV IgA seropositivity (antibody concentration ≥20 U/mL) may serve as a useful correlate of efficacy in clinical trials of RV1 vaccines.

The human rotavirus vaccine Rotarix™ in infants: an integrated analysis of safety and reactogenicity

An integrated analysis of safety and reactogenicity data was undertaken for 28 randomized, placebo-controlled, double-blind Phase II and III trials (DBRCTs) of the oral live-attenuated human rotavirus vaccine, Rotarix™ (GlaxoSmithKline Vaccines). Healthy infants aged 6-20 wk received 2 or 3 doses of vaccine (n=56562) or placebo (n=45512) at 4- to 8-wk intervals. Solicited adverse events (AEs) were recorded for 8 d after each dose of vaccine or placebo. Unsolicited AEs, serious AEs (SAEs), and deaths were evaluated over 31-d post-vaccination follow-up periods. 95% confidence intervals (CIs) for the relative risk (RR) across studies excluding "1.0" signified potential imbalances between the 2 groups. The incidence of each solicited AE of any or Grade 3 severity was similar between groups. The incidence of all unsolicited AEs of any (RR=0.99 [95% CI: 0.94-1.04]; P=0.72) or Grade 3 severity (RR=0.91 [95% CI: 0.77-1.08]; P=0.31) was similar between groups. A significantly higher proportion of SAEs were reported in the placebo group compared with the vaccine group (RR=0.9 [95% CI: 0.82-0.98]; P=0.01). The incidence of death was low and similar between the 2 groups (0.13% in the vaccine group and 0.11% in the placebo group; RR=1.14 [95% CI: 0.78-1.68]; P=0.54). Very few cases of intussusception were reported (11 and 7 in the vaccine and placebo groups, respectively; RR=1.39 [95% CI: 0.49-4.27]; P=0.66). In conclusion, results of this analysis of DBRCTs show that the human rotavirus vaccine Rotarix™ has a reactogenicity and safety profile similar to placebo.

Human rotavirus vaccine (RIX4414) efficacy in the first two years of life: a randomized, placebo-controlled trial in China

Rotaviruses (RV) are a major cause of severe gastroenteritis (GE) in children aged<5 y. For the first time in China, we assessed the efficacy of two oral doses of the human rotavirus vaccine (RIX4414) in infants during the first two years of life (113808/NCT01171963). Healthy infants aged 6-16 weeks were randomized (1:1) to receive two oral doses of either the RIX4414 vaccine/placebo according to a 0, 1 month schedule. Vaccine efficacy (VE) against severe RVGE was assessed from two weeks post-Dose 2 up until the end of the second RV season and calculated with its 95% confidence intervals (CI). The primary efficacy objective was met if the lower limit of the 95% CI on VE was ≥10%. Unsolicited symptoms reported during the 31-d post-vaccination follow-up period and serious adverse events (SAEs) reported throughout the study were assessed. Of 3333 enrolled infants, 3148 were included in the according-to-protocol efficacy cohort. Over two consecutive RV seasons, fewer severe RVGE episodes were reported in the RIX4414 group (n=21) vs. the placebo group (n=75). VE against severe RVGE was 72% (95% CI: 54.1-83.6); the lower limit of the 95% CI on VE was >10%. The number of unsolicited symptoms and SAEs reported was similar between both groups. Thirteen deaths (RIX4414=6; placebo=7) occurred during the study. All SAEs and deaths in the RIX4414 group were considered unrelated to vaccination. Two oral doses of RIX4414 vaccine provided a substantial level of protection against severe RVGE in Chinese children during the first two years of life.

New concepts in diagnostics for infectious diarrhea

Conventional approaches to the diagnosis of infectious diarrhea must include several modalities to detect an array of potential viruses, bacteria, and parasites. We will provide a general overview of the wide range of diagnostic modalities available for enteropathogens, briefly discuss some of the limitations of conventional methods, and then focus on new molecular methods, including real-time PCR and next-generation sequencing. In particular, we will discuss quantitation of pathogen load with these techniques. We will then describe examples whereby novel diagnostics may help illuminate the etiology of infectious diarrhea, where they may not, and how they may benefit studies of immunity to enteric infections.

Investigation of a regulatory agency enquiry into potential porcine circovirus type 1 contamination of the human rotavirus vaccine, Rotarix: approach and outcome

In January 2010, porcine circovirus type 1 (PCV1) DNA was unexpectedly detected in the oral live-attenuated human rotavirus vaccine, Rotarix (GlaxoSmithKline [GSK] Vaccines) by an academic research team investigating a novel, highly sensitive analysis not routinely used for adventitious agent screening. GSK rapidly initiated an investigation to confirm the source, nature and amount of PCV1 in the vaccine manufacturing process and to assess potential clinical implications of this finding. The investigation also considered the manufacturer's inactivated poliovirus (IPV)-containing vaccines, since poliovirus vaccine strains are propagated using the same cell line as the rotavirus vaccine strain. Results confirmed the presence of PCV1 DNA and low levels of PCV1 viral particles at all stages of the Rotarix manufacturing process. PCV type 2 DNA was not detected at any stage. When tested in human cell lines, productive PCV1 infection was not observed. There was no immunological or clinical evidence of PCV1 infection in infants who had received Rotarix in clinical trials. PCV1 DNA was not detected in the IPV-containing vaccine manufacturing process beyond the purification stage. Retrospective testing confirmed the presence of PCV1 DNA in Rotarix since the initial stages of its development and in vaccine lots used in clinical studies conducted pre- and post-licensure. The acceptable safety profile observed in clinical trials of Rotarix therefore reflects exposure to PCV1 DNA. The investigation into the presence of PCV1 in Rotarix could serve as a model for risk assessment in the event of new technologies identifying adventitious agents in the manufacturing of other vaccines and biological products.

Pharmacoeconomic spotlight on rotavirus vaccine RIX4414 (Rotarix™) in developed countries

The most common cause of severe diarrhea in infants and young children is rotavirus gastroenteritis (RVGE), which is associated with significant morbidity, healthcare resource use, and direct and indirect costs in industrialized nations. The monovalent rotavirus vaccine RIX4414 (Rotarix™) is administered as a two-dose oral series in infants and has demonstrated protective efficacy against RVGE in clinical trials conducted in developed countries. In addition, various naturalistic studies have demonstrated ‘real-world’ effectiveness after the introduction of widespread rotavirus vaccination programs in the community setting.

Numerous cost-effectiveness analyses have been conducted in developed countries in which a universal rotavirus vaccination program using RIX4414 was compared with no universal rotavirus vaccination program. There was a high degree of variability in base-case results across studies even when the studies were conducted in the same country, often reflecting differences in the selection of data sources or assumptions used to populate the models. In addition, results were sensitive to plausible changes in a number of key input parameters. As such, it is not possible to definitively state whether a universal rotavirus vaccination program with RIX4414 is cost effective in developed countries, although results of some analyses in some countries suggest this is the case. In addition, international guidelines advocate universal vaccination of infants and children against rotavirus. It is also difficult to draw conclusions regarding the cost effectiveness of rotavirus vaccine RIX4414 relative to that of the pentavalent rotavirus vaccine, which is administered as a three-dose oral series. Although indirect comparisons in cost-effectiveness analyses indicate that RIX4414 provided more favorable incremental cost-effectiveness ratios when each vaccine was compared with no universal rotavirus vaccination program, results were generally sensitive to vaccine costs. Actual tender prices of a full vaccination course for each vaccine were not known at the time of the analyses and therefore had to be estimated.

Efficacy, immunogenicity, and safety of two doses of a tetravalent rotavirus vaccine RRV-TV in Ghana with the first dose administered during the neonatal period

BACKGROUND

Oral rhesus/rhesus-human reassortant rotavirus tetravalent vaccine (RRV-TV) was licensed in 1998 but withdrawn in 1999 due to a rare association with intussusception, which occurred disproportionately in infants receiving their first dose at ≥90 days of age. This study examined RRV-TV for the prevention of rotavirus gastroenteritis (RV-GE) in Ghana, West Africa, with infants receiving the first dose during the neonatal period and the second before 60 days of age.

METHODS

In a double-blinded, randomized, placebo-controlled trial in Navrongo, Ghana, we recruited neonates to receive 2 doses of RRV-TV or placebo and followed them to age 12 months.

RESULTS

In the intention-to-treat population of 998 infants, we measured a vaccine efficacy of 63.1% against RV-GE of any severity associated with any of the 4 serotypes represented in the vaccine and 60.7% against RV-GE associated with any rotavirus serotype.

CONCLUSIONS

RRV-TV in a 2-dose schedule with the first dose during the neonatal period is efficacious in preventing RV-GE in rural Ghana. Neonatal dosing results in early protection and may be the optimum schedule to avoid or significantly reduce intussusception, now reported to be associated in international settings with the 2 most widely marketed, licensed, live virus, oral rotavirus vaccines.

Changing profile of rotavirus genotypes in Bangladesh, 2006-2012

Background

Rotavirus is the leading cause of severe diarrhea in infants and young children worldwide including Bangladesh. Unlike what was seen in high-income countries, the licensed rotavirus vaccines did not show high efficacy in Bangladeshi trials. We assessed rotavirus prevalence and genotypes in Bangladesh over six-year period to provide baseline information on the rotavirus burden and changing profile in the country.

Methods

This study was conducted from June 2006 to May 2012 in Matlab, Bangladesh. Group A rotaviruses were detected in stools collected from diarrhea patients by ELISA and genotyped using multiplex reverse transcription PCR followed by nucleotide sequencing.

Results

Of the 9678 stool samples, 20.3% were positive for rotavirus. The most predominant genotype was G1P[8] (22.4%), followed by G9P[8] (20.8%), G2P[4] (16.9%) and G12P[8] (10.4%). Mixed infections were detected in 14.2% of the samples. Emergence of an unusual strain, G9P[4] was documented during 2011–12. Several amino acid mismatches in the antigenic epitopes of VP7 and VP4 between Bangladeshi and the vaccine strains were identified.

Conclusions

Our study provides important information on rotavirus genotypes that should be considered for the selection and introduction of rotavirus vaccines in Bangladesh.

Effectiveness of monovalent and pentavalent rotavirus vaccine

OBJECTIVE

Previous US evaluations have not assessed monovalent rotavirus vaccine (RV1, a G1P[8] human rotavirus strain) effectiveness, because of its later introduction (2008). Using case-control methodology, we measured the vaccine effectiveness (VE) of the 2-dose RV1 and 3-dose pentavalent vaccine (RV5) series against rotavirus disease resulting in hospital emergency department or inpatient care.

METHODS

Children were eligible for enrollment if they presented to 1 of 5 hospitals (3 in Georgia, 2 in Connecticut) with diarrhea of ≤10 days' duration during January through June 2010 or 2011, and were born after RV1 introduction. Stools were collected; immunization records were obtained from providers and state electronic immunization information system (IIS). Case-subjects (children testing rotavirus antigen-positive) were compared with 2 control groups: children testing rotavirus negative and children selected from IIS.

RESULTS

Overall, 165 rotavirus-case subjects and 428 rotavirus-negative controls were enrolled. Using the rotavirus-negative controls, RV1 VE was 91% (95% confidence interval [CI] 80 to 95) and RV5 VE was 92% (CI 75 to 97) among children aged ≥8 months. The RV1 VE against G2P[4] disease was high (94%, CI 78 to 98), as was that against G1P[8] disease (89%, CI 70 to 96). RV1 effectiveness was sustained among children aged 12 through 23 months (VE 91%; CI 75 to 96). VE point estimates using IIS controls were similar to those using rotavirus-negative controls.

CONCLUSIONS

RV1 and RV5 were both highly effective against severe rotavirus disease. RV1 conferred sustained protection during the first 2 years of life and demonstrated high effectiveness against G2P[4] (heterotypic) disease.

Rotavirus genotypes in children in the community with diarrhea in Madagascar

In the context of the possible introduction of a preventive vaccine against rotaviruses in Madagascar, the G and P genotypes distribution of the rotaviruses circulating in the children in Madagascar was studied, and the presence of emerging genotypes and unusual strains were assessed. From February 2008 to May 2009, 1,679 stools specimens were collected from children ≤5 years old with diarrhea. ELISA was used for antigen detection, and molecular amplification of VP7 and VP4 gene fragments was used for genotyping. Rotavirus antigen was detected in 104 samples (6.2%). Partial sequences of VP7 and VP4 genes were obtained from 81 and 80 antigen-positive stools, respectively. The most frequent G and P types combinations detected were G9P[8] (n = 51; 64.6%), followed by G1P[8] (n = 15; 18.9%), and G1P[6] (n = 8; 10.1%). A few unusual G-P combinations, such as G4P[6] (n = 3; 3.8%), G9P[6] (n = 1; 1.3%), and G3P[9] reassortant feline human virus (n = 1; 1.3%) were identified. Both VP4 and VP7 sequences in one of the three G4P[6] isolates were closely related to those in porcine strains, and one was a reassortant human porcine virus. These findings give an overview of the strains circulating in Madagascar and should help public health authorities to define a vaccine strategy.

Human G9P[8] rotavirus strains circulating in Cameroon, 1999-2000: Genetic relationships with other G9 strains and detection of a new G9 subtype

Group A rotaviruses (RV-A) are the leading cause of viral gastroenteritis in children worldwide and genotype G9P[8] is one of the five most common genotypes detected in humans. In order to gain insight into the degree of genetic variability of G9P[8] strains circulating in Cameroon, stool samples were collected during the 1999-2000 rotavirus season in two different geographic regions in Cameroon (Southwest and Western Regions). By RT-PCR, 15 G9P[8] strains (15/89=16.8%) were identified whose genomic configurations was subsequently determined by complete or partial gene sequencing. In general, all Cameroonian G9 strains clustered into current globally-spread sublineages of the VP7 gene and displayed 86.6-100% nucleotide identity amongst themselves and 81.2-99.5% nucleotide identity with global G9 strains. The full genome classification of all Cameroonian strains was G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 but phylogenetic analysis of each gene revealed that the strains were spread across 4 or more distinct lineages. An unusual strain, RVA/Human-wt/CMR/6788/1999/G9P[8], which shared the genomic constellation of other Cameroonian G9P[8] strains, contained a novel G9 subtype which diverged significantly (18.8% nucleotide and 19% amino acid distance) from previously described G9 strains. Nucleotide and amino acid alignments revealed that the 3' end of this gene is highly divergent from other G9 VP7 genes suggesting that it arose through extensive accumulation of point mutations. The results of this study demonstrate that diverse G9 strains circulated in Cameroon during 1999-2000.

Cost effectiveness of infant vaccination for rotavirus in Canada

INTRODUCTION

Rotavirus is the main cause of gastroenteritis in Canadian children younger than five years of age, resulting in significant morbidity and cost. The present study provides evidence on the cost effectiveness of two alternative rotavirus vaccinations (RotaTeq [Merck Frosst Canada Ltd, Canada] and Rotarix [GlaxoSmithKline, Canada]) available in Canada.

METHODS

Analysis was conducted through a Markov model that followed a cohort of children from birth to five years of age. Analysis used pertinent data on the natural history of rotavirus and the effects of vaccination. Estimates of heath care costs for children requiring hospitalizations and emergency department visits were derived from the Canadian Immunization Monitoring Program, Active (IMPACT) surveillance, emergency department studies, as well as other Canadian studies. The model estimated the effect of vaccination on costs and quality-adjusted life years (QALYs).

RESULTS

The incremental cost per QALY gained from the health care system perspective was $122,000 for RotaTeq and $108,000 for Rotarix. From the societal perspective, both vaccination strategies were dominant - both cost saving and more effective. The cost-effectiveness of vaccination is dependent on the mode of administration, the perspective adopted and the cost of the vaccine.

CONCLUSIONS

From a societal perspective, a universal vaccination program against rotavirus will be both cost saving and more effective than no vaccination. Becasue the majority of rotavirus infections do not require emergency department visits or hospital admission, from a health care system perspective, a program would not be considered cost effective.

Reactogenicity and safety of a liquid human rotavirus vaccine (RIX4414) in healthy adults, children and infants in China: randomized, double-blind, placebo-controlled Phase I studies

We report the findings of three randomized, double-blind, placebo-controlled Phase I studies undertaken to support licensure of the liquid formulation of the human G1P[8] rotavirus (RV) vaccine (RIX4414; GlaxoSmithKline Biologicals SA) in China. Healthy adults aged 18–45 y (n = 48) and children aged 2–6 y (n = 50) received a single dose of the human RV vaccine or placebo. Healthy infants (n = 50) aged 6–16 weeks at the time of first vaccination received two oral doses of the human RV vaccine or placebo according to a 0, 1 mo schedule. In infants, blood samples were collected prior to vaccination and one month post-dose 2 to assess anti-RV IgA antibody concentrations using ELISA. Stool samples were collected from all infants on the day of each vaccination, at 7 and 15 d after each vaccination and one month post-dose 2. Stool samples were analyzed by ELISA for detection of RV antigen to assess RV antigen excretion. The reactogenicity profile of the human RV vaccine was found to be comparable to that of placebo in all age groups studied. The anti-RV IgA antibody seroconversion rate in infants after two vaccine doses was 86.7% (95% CI: 59.5–98.3). Vaccine take in infants who received the liquid human RV vaccine was 86.7% (95% CI: 59.5–98.3). A Phase III efficacy study of the human RV vaccine in the infant population in China has now been completed (ROTA-075/NCT01171963).

Impact of rotavirus vaccination in Australian children below 5 years of age: a database study

This study was conducted to assess the impact of administration of two-dose rotavirus (RV) vaccine (RIX4414; GlaxoSmithKline Vaccines) among children aged less than 5 y in three states/territories of Australia. Aggregated and de-identified data on rotavirus gastroenteritis (RVGE) and all-cause gastroenteritis (AGE) from July 1998–June 2009 were obtained from the Australian Institute of Health and Welfare database. The baseline incidence (July 1998–June 2006) of RVGE hospitalizations before RV vaccine introduction in New South Wales (NSW), the Australian Capital Territory (ACT) and the Northern Territory (NT) were 33.75, 42.93 and 288.67 per 10 000 child-years, respectively among children aged 0–11 mo. Following RV vaccine introduction in NSW, the ACT and the NT, incidence of RVGE hospitalizations reduced to 13.06, 17.35 and 47.52 per 10 000 child-years, respectively, during July 2007–June 2008 and 3.87, 8.40 and 122.79 per 10,000 child-years, respectively, during July 2008–June 2009 among children aged 0–11 mo. Reductions in RVGE and AGE were also observed in all children below 5 y of age in NSW and the ACT. Overall reduction in hospitalizations due to RVGE and AGE was observed following RV vaccine introduction into the NIP in Australia.

Treatment and prevention of rotavirus infection in children

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and continues to have a major global impact on childhood morbidity and mortality. No antiviral therapy is available. Treatment of rotavirus gastroenteritis is limited to rehydration therapy. Recently, therapies, such as probiotics, have been developed as adjuncts to rehydration therapy. Two effective rotavirus vaccines are available and recommended for routine immunization of all infants. These vaccines have been introduced in both developed and developing countries. As rotavirus vaccines are implemented, studies that assess health impact, indirect benefits, and strain changes after the introduction of rotavirus vaccine have been reported. In the United States, rotavirus vaccination has led to dramatic drops in severe rotavirus-related hospitalizations and has reduced emergency room visits. Herd immunity has also been noted after routine rotavirus immunization. There have been no significant strain shifts or escape mutants noted since the introduction of rotavirus vaccines.

Rotavirus vaccination in central Europe

Each year, rotavirus (RV) infection is the leading cause of acute gastroenteritis requiring hospitalisation and of nosocomially transmitted diseases in children younger than 5 years across Central European Vaccination Awareness Group (CEVAG) countries; however, inadequate surveillance systems and lack of routine RV testing still exist in most CEVAG countries, making it difficult to accurately assess the present burden of acute RV gastroenteritis in the younger population. Furthermore, routine immunisation of infants with RV vaccines has not been implemented, and no official and uniform recommendations exist in most of the countries in these territories. The present study provides CEVAG country-specific estimates of the disease burden of RV gastroenteritis among the youngest population and presents evidence-based advice on the use of RV vaccines in the region, while providing a framework for vaccination at the national level.

Lack of nonspecific protection against all-cause nonrotavirus gastroenteritis by vaccination with orally administered rotavirus vaccine

OBJECTIVES

Acute gastroenteritis (AGE) is recognized as a global, common threat to child survival, especially in developing countries. Rotavirus, in particular, has been implicated as a leading cause of severe AGE; however, there are numerous other pathogens that also cause AGE. Several studies have demonstrated that oral vaccination against rotavirus has generated the unanticipated benefit of protecting against AGE caused by nonrotavirus pathogens.

METHODS

Safety and efficacy of the pentavalent bovine-human reassortant rotavirus vaccine were studied in multiple populations, including children of the Navajo and White Mountain Apache tribes in the southwestern United States. Stool specimens were collected from children with AGE and tested for rotavirus using an enzyme immunoassay. Analyses were conducted to detect the presence or absence of a vaccine effect on incidence, severity, and duration of AGE in which rotavirus was not detected.

RESULTS

The majority of AGE (N = 558: 472 nonrotavirus vs 86 rotavirus) occurred between August 2002 and March 2004 among children ranging from ages 4 to 23 months. The incidence of nonrotavirus AGE was similar by vaccine groups with an incidence rate ratio of 1.07 (incidence rate ratio = vaccinated/unvaccinated, 95% confidence interval 0.89-1.29). The hazards of first, second, third, or any AGE in which rotavirus was not detected differed little by vaccination status (P > 0.05). Duration of symptoms and severity of nonrotavirus AGE were similar by vaccine group.

CONCLUSIONS

There was no vaccine effect on frequency or severity of nonrotavirus AGE.

[Incidence of rotavirus gastroenteritis among children under 5 years consulting a paediatrician or a general practitioner in France]

BACKGROUND

Rotavirus (RV) is the main infectious agent of severe acute gastroenteritis (AGE) in infants and children under 5 years. Given the recent availability of new vaccines, it is important to accurately assess the incidence of rotavirus gastroenteritis (GERV) and their medical and epidemiological consequences.

METHODS

This work is the French part of study program called SPRIK, a multicenter, prospective, observational study conducted from October 2005 to May 2007 to estimate the annual incidence of GERV within children under 5 years visiting a general practitioner or pediatrician. It presents data collected by 41 general practitioners and 36 paediatricians located throughout the French metropolitan territory. A stool sample was taken for every child. Rotavirus presence was sought by the physician using a rapid immunochromatographic test. French results are presented in this article.

RESULTS

A total of 1648 GEA episodes corresponding to 1463 eligible patients were included in the study mainly from December to May (peak in February-March). The incidence rate of GERV leading to consultations in general practice was 1357 cases per 100,000 patient-years (PY) (1.36%), with a 95% confidence interval of [1345-1368]. The peak incidence occurs before 2 years. GERV accounted for 21% of all GEA cases seen by paediatricians and general practitioners. Patients with GERV were younger (14.1 ± 10.8 versus 18.4 ± 13.9 months for other GEA, P<0.0001) and had more severe clinical symptoms: presence of fever (32.6% versus 20.0%, P<0.0001), behavioural symptoms (45.6% versus 20.8%, P<0.0001) and dehydration (48.7% versus 21.2%, P<0.0001). GERV episodes were considered severe in 79.7% of cases, using the Vesikari scale. More than 86% patients received oral rehydration during the episode and 13 patients (5.8%) were hospitalized. Nearly 80% GERV episodes were considered severe using the Vesikari scale. Main genotypes were G1P[8] rotavirus (44%) and G9P[8] rotavirus (35%) types.

CONCLUSION

The incidence rate reported in this study is close to results of previous studies done in Europe. The frequency and severity relative to GERV support vaccination in very young children to reduce the burden associated with this pathology.

Group A rotavirus universal mass vaccination: how and to what extent will selective pressure influence prevalence of rotavirus genotypes?

Two human group A rotavirus (RVA) vaccines are available and highly effective in preventing severe gastroenteritis caused by all commonly circulating human RVA genotypes. The effect of universal mass vaccination on the RVA genotype distribution is discussed based on the knowledge of complete RVA genotype constellations, data from clinical efficacy trials and effectiveness studies, and genotype surveillance data from countries with universal mass vaccination programs. The theoretically predicted relative enrichment of RVA strains with the G2P[4] DS-1-like genotype constellation in regions with high coverage by Rotarix(®) (GlaxoSmithKline Biologicals, Rixensart, Belgium) seems to become apparent. A G3P[8] genotype increase, which was noted in several regions with a high coverage of RotaTeq(®) (Merck and Co., Inc., NJ, USA), is more difficult to explain based on the theoretical considerations.

Sequence and phylogenetic analyses of human rotavirus strains: comparison of VP7 and VP8(∗) antigenic epitopes between Tunisian and vaccine strains before national rotavirus vaccine introduction

Group A rotaviruses (RVA) are the leading cause of severe gastroenteritis in infants and young children worldwide. Due to their epidemiological complexity, it is important to compare the genetic characteristics of vaccine strains with the RVA strains circulating before the introduction of the vaccine in the Tunisian immunization program. In the present study, the nucleotide sequences of VP7 and VP8∗ (n=31), the main targets for neutralizing antibodies, were determined. Comparison of antigenic epitopes of 11 G1P[8], 12 G2P[4], 4 G3P[8], 2 G4P[8], 1 G6P[9] and 1 G12P[8] RVA strains circulating in Tunisia from 2006 to 2011 with the RVA strains present in licensed vaccines showed that multiple amino acid differences existed in or near putative neutralizing domains of VP7 and VP8∗. The Tunisian G3 RVA strains were found to possess a potential extra N-linked glycosylation site. The Tunisian G4 RVA were closely related to the G4 vaccine strain in RotaTeq, belonging to the same lineage, but the alignment of their VP7 amino acids revealed an insertion of an asparagine residue at position 76 which is close to a glycosylation site (aa 69-71). Despite several differences detected between Tunisian and vaccine strains, which may affect binding of neutralizing antibodies, both vaccines are known to protect against the vast majority of the circulating genotypes, providing an indication of the high vaccine efficiency that can be expected in a future rotavirus immunization program.

Targeted rotavirus vaccination of high-risk infants; a low cost and highly cost-effective alternative to universal vaccination

BACKGROUND

The cost-effectiveness of universal rotavirus (RV) vaccination is controversial in developed countries. As a result, RV vaccination programs do not currently exist in most European countries. Hospitalization is the main driver of RV disease costs, and prematurity, low birth weight (LBW) and underlying medical conditions have been associated with RV hospitalization and complications. We investigated the cost-effectiveness of targeted RV vaccination of high-risk infants and universal RV vaccination versus no vaccination.

METHODS

Disease burden, mortality and healthcare costs of RV hospitalization for children with and without prematurity, LBW and congenital pathology were quantified in two hospital-based observational studies in the Netherlands. Cost-effectiveness analysis was based on an age-structured stochastic multi-cohort model of the Dutch population comparing universal RV vaccination and targeted vaccination of high-risk infants to no vaccination. The primary endpoint was the incremental cost-effectiveness ratio (ICER), with a threshold of €35,000/quality-adjusted life year (QALY) from the healthcare provider perspective. Sensitivity analyses included vaccine price and coverage, herd-immunity and QALY losses.

RESULTS

A total of 936 children with RV infection were included. Prematurity, LBW and congenital pathology were associated with increased risks of RV hospitalization (relative risks (RR) ranging from 1.6 to 4.4), ICU admission (RR ranging from 4.2 to 7.9), prolonged hospital stay (1.5 to 3.0 excess days) and higher healthcare costs (€648 to €1,533 excess costs). Seven children succumbed due to RV complications, all belonging to the high-risk population. Targeted RV vaccination was highly cost-effective and potentially cost-saving from the healthcare provider perspective with ICERs below €20,000/QALY in all scenarios with total (undiscounted) annual healthcare costs between -€0.1 and €0.5 million/year. Results were most sensitive to mortality rates, but targeted vaccination remained highly cost-effective up to reductions of 90% compared to observed mortality. Universal RV vaccination was not considered cost-effective (mean ICER: €60,200/QALY) unless herd-immunity and caretaker QALY losses were included and vaccine prices were €60 at most (mean ICER: €21,309/QALY).

CONCLUSION

We recommend targeted RV vaccination for high-risk infants in developed countries.

Sustained low hospitalization rates after four years of rotavirus mass vaccination in Austria

This hospital based surveillance study evaluates the effects of the rotavirus mass vaccination program, which was initiated in Austria in August 2007. Since then, incidence rates of rotavirus hospitalizations in children <15 years of age have decreased by 70% and 64% in 2010 and 2011 compared to the pre-vaccination era (2001-2005). Incidence rates were highest in children <90 days of age, highlighting the importance of the early start of active rotavirus immunization. In children between 2 and 3.5 years in 2011, who were in the second and third year after vaccination in the universal mass vaccination program, incidence rates remained low suggesting sustained protection after vaccination up to three years. In the years 2010 and 2011, field effectiveness of the vaccines was between 79% and 96%, depending on the assumptions made for children without information on vaccination history. From genotyping an increase of the prevalence of G2P[4] in children with breakthrough infection (disease despite vaccination) can be suspected. The rate of severe adverse events was 1.3-1.5 per 10(-5) administered doses of rotavirus vaccines and no death, intussusception or Kawasaki disease was reported in 2010 and 2011 following rotavirus vaccination.

Effectiveness of pentavalent and monovalent rotavirus vaccines in concurrent use among US children <5 years of age, 2009-2011

BACKGROUND

We assessed vaccine effectiveness (VE) for RotaTeq (RV5; 3 doses) and Rotarix (RV1; 2 doses) at reducing rotavirus acute gastroenteritis (AGE) inpatient and emergency department (ED) visits in US children.

METHODS

We enrolled children <5 years of age hospitalized or visiting the ED with AGE symptoms from November 2009-June 2010 and from November 2010-June 2011 at 7 medical institutions. Fecal specimens were tested for rotavirus by enzyme immunoassay and genotyped. Vaccination among laboratory-confirmed rotavirus cases was compared with rotavirus-negative AGE controls. Regression models calculated VE estimates for each vaccine, age, ethnicity, genotype, and clinical setting.

RESULTS

RV5-specific analyses included 359 rotavirus cases and 1811 rotavirus-negative AGE controls. RV1-specific analyses included 60 rotavirus cases and 155 rotavirus-negative AGE controls. RV5 and RV1 were 84% (95% confidence interval [CI], 78%-88%) and 70% (95% CI, 39%-86%) effective, respectively, against rotavirus-associated ED visits and hospitalizations combined. By clinical setting, RV5 VE against ED and inpatient rotavirus-associated visits was 81% (95% CI, 70%-84%) and 86% (95% CI, 74%-91%), respectively. RV1 was 78% (95% CI, 46%-91%) effective against ED rotavirus disease; study power was insufficient to evaluate inpatient RV1 VE. No waning of immunity was evident during the first 4 years of life for RV5, nor during the first 2 years of life for RV1. RV5 provided genotype-specific protection against each of the predominant strains (G1P[8], G2P[4], G3P[8], G12P[8]), while RV1 VE was statistically significant for the most common genotype, G3P[8].

CONCLUSIONS

Both RV5 and RV1 significantly protected against medically attended rotavirus gastroenteritis in this real-world assessment.

Efficacy, safety and immunogenicity of a human rotavirus vaccine (RIX4414) in Hong Kong children up to three years of age: a randomized, controlled trial

BACKGROUND

A phase III, double-blind, randomized, controlled trial was conducted in Hong Kong to evaluate the efficacy, safety and immunogenicity of a human rotavirus vaccine, RIX4414 (Rotarix) against severe rotavirus gastroenteritis in children up to three years of age.

METHODS

Healthy infants aged 6-12 weeks were enrolled between 08-December-2003 and 31-August-2005 and received two oral doses of either RIX4414 vaccine (N=1513) or placebo (N=1512) given 2 months apart. Vaccine efficacy was assessed from two weeks post-Dose 2 until the children were two and three years of age. Anti-rotavirus IgA seroconversion rate was calculated pre-vaccination and 1-2 months post-Dose 2 using ELISA (cut-off=20 U/mL) for 100 infants. Safety was assessed until the children were two years of age; serious adverse events (SAEs) were recorded throughout the study period.

RESULTS

In children aged two and three years of life, vaccine efficacy against severe rotavirus gastroenteritis was 95.6% (95% CI: 73.1%-99.9%) and 96.1% (95% CI: 76.5%-99.9%), respectively. The seroconversion rate 1-2 months after the second dose of RIX4414 was 97.5% (95% CI: 86.8%-99.9%). At least one SAE was recorded in 439 and 477 infants who were administered RIX4414 and placebo, respectively (p-value=0.130). Six intussusception cases were reported (RIX4414=4; placebo=2) and none was assessed to be vaccine-related.

CONCLUSION

RIX4414 was efficacious, immunogenic and safe in the prevention of rotavirus gastroenteritis for at least two years post-vaccination in Hong Kong children.

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.

Effectiveness of an incomplete RotaTeq (RV5) vaccination regimen in preventing rotavirus gastroenteritis in the United States

BACKGROUND

Effectiveness of the pentavalent rotavirus vaccine (RV5) after administration of the complete (3 dose) regimen has been demonstrated in a real-world setting. This study assessed the effectiveness of RV5 following partial completion of the 3-dose regimen.

METHODS

Using a large national health insurance claims database, 2 cohorts of infants (those who received RV5 and a concurrent group who received diphtheria-tetanus-acellular pertussis, but not RV5) were followed through the 2007 and 2008 rotavirus seasons (January 1 to May 31) to identify cases of rotavirus gastroenteritis and all-cause gastroenteritis resulting in medical care encounters. Vaccine effectiveness following the first and the second RV5 doses was estimated by quantifying reductions in hospitalizations, emergency department (ED) and physician office visits.

RESULTS

A first RV5 dose was received by 42,306 infants whereas 28,417 infants in the concurrent comparison group received a first diphtheria-tetanus-acellular pertussis dose; 43,704 infants received a second RV5 dose, and 31,810 infants received a second diphtheria-tetanus-acellular pertussis dose. One dose of RV5 was associated with 88% effectiveness against rotavirus gastroenteritis hospitalizations and ED visits and 44% effectiveness against all-cause gastroenteritis hospitalizations and ED visits. A 2-dose regimen of RV5 was associated with 94% effectiveness against rotavirus gastroenteritis hospitalizations and ED visits and 40% effectiveness against all-cause gastroenteritis hospitalizations and ED visits.

CONCLUSION

The RV5 vaccine exhibits effectiveness against rotavirus gastroenteritis even before completing the full 3-dose regimen. These results are of particular relevance when considering the benefits of a partially completed rotavirus vaccine series.

Consensus recommendations on immunization and IAP immunization timetable 2012

JUSTIFICATION

Vaccinology today is a rapidly changing specialty of medical science where new developments are regularly taking place. There is a need to review/revise recommendations about existing vaccines in the light of recent information.

PROCESS

Following an IAPCOI meeting in December 2011, a draft statement was prepared and circulated among the meeting participants to arrive at a consensus.

OBJECTIVES

To review and issue recommendations on the recent contentious issues pertaining to rotavirus, Hib, and pneumococcal conjugate vaccines, and to revise recommendations for 2012 Immunization timetable for pediatricians in office practice.

RECOMMENDATIONS

IAPCOI abolished the earlier categorization of vaccines in four categories. On rotavirus, the committee stresses the need of having more data on disease burden in India. Further, there is a need to optimize use of rotavirus vaccines in India to achieve higher yields in term of protective efficacy. For the want of adequate data, the committee is not able to issue any specific recommendation on the suitability of a particular rotavirus vaccine (monovalent vs multivalent) for the country. The committee also acknowledges a small risk of acute intussusception following use of current generation of rotavirus vaccines and recommends inclusion of the history of intussusception in the past as an absolute contraindication. The committee concludes that there are no safety concerns of Hib vaccines as reported frequently in lay media. On the disease burden of pneumococcal diseases, the committee concludes that there is a need of conducting more community based studies to gather more evidence. Similarly, the data on prevalence of different pneumococcal serotypes in the country is sparse and limited to few hospital based studies. There is need of establishing real-time multisite pneumococcal disease surveillance in the country. Due to scarcity of data on the prevalence of pneumococcal serotypes and non-typeable hemophilus influenza (NTHi) in India, it is difficult to comment on the superiority of one pneumococcal conjugate vaccine over other. The committee also revised the recommendations for the year 2012.

Indirect protection of adults from rotavirus by pediatric rotavirus vaccination

BACKGROUND

Pediatric vaccination has resulted in declines in disease in unvaccinated individuals through decreasing pathogen circulation in the community. About 2 years after implementation of pediatric rotavirus vaccination in the United States, dramatic declines in rotavirus disease were observed in both vaccinated and unvaccinated children. Whether this protection extends to adults is unknown.

METHODS

The prevalence of rotavirus, as determined by Rotaclone enzyme immunoassay, in adults who had stools submitted for bacterial stool culture (BSC) between February to May to Northwestern Memorial Hospital, Chicago, was compared between the prepediatric impact era (2006-2007) and the pediatric impact era (2008-2010). Isolates were genotyped and clinical characteristics of those with rotavirus were compared.

RESULTS

Of the 5788 BSC sent, 4725 met inclusion criteria and 3530 of these (74.7%) were saved for rotavirus testing. The prevalence of rotavirus among adults who had stool sent for BSC declined from 4.35% in 2006-2007 to 2.24% in 2008-2010 (a relative decline of 48.4%; P = .0007). The decline in the prevalence of rotavirus was of similar significant magnitude in both outpatients and inpatients. Marked year-to-year variability was observed in circulating rotavirus genotypes, with strain G2P[4] accounting for 24%; G1P[8], 22%; G3P[8], 11%; and G12P[6], 10% overall. About 30% of adults from whom rotavirus was isolated were immunocompromised and this remained constant.

CONCLUSIONS

Pediatric rotavirus vaccination correlated with a relative decline of almost 50% in rotavirus identified from adult BSC during the peak rotavirus season, suggesting that pediatric rotavirus vaccination protects adults from rotavirus.