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

The cost-effectiveness of rotavirus vaccination: Comparative analyses for five European countries and transferability in Europe

Cost-effectiveness analyses are usually not directly comparable between countries because of differences in analytical and modelling assumptions. We investigated the cost-effectiveness of rotavirus vaccination in five European Union countries (Belgium, England and Wales, Finland, France and the Netherlands) using a single model, burden of disease estimates supplied by national public health agencies and a subset of common assumptions. Under base case assumptions (vaccination with Rotarix, 3% discount rate, health care provider perspective, no herd immunity and quality of life of one caregiver affected by a rotavirus episode) and a cost-effectiveness threshold of euro30,000, vaccination is likely to be cost effective in Finland only. However, single changes to assumptions may make it cost effective in Belgium and the Netherlands. The estimated threshold price per dose for Rotarix (excluding administration costs) to be cost effective was euro41 in Belgium, euro28 in England and Wales, euro51 in Finland, euro36 in France and euro46 in the Netherlands.

Prevention of the murine model of biliary atresia after live rotavirus vaccination of dams

PURPOSE

Biliary atresia (BA) is a neonatal disease that results in the obliteration of the biliary tree. The murine model of BA has been established where rhesus rotavirus (RRV) infection of newborn mice leads to an obstructive cholangiopathy. We determined whether maternal postconception rotavirus vaccination could prevent the murine model of BA.

MATERIALS AND METHODS

Female mice were mated and injected intraperitoneally with one of the following materials: purified rotavirus strains RRV or Wa, high or low-dose Rotateq (Merck and Co Inc, Whitehouse Station, NJ) (a pentavalent rotavirus vaccine [PRV]), purified recombinant viral antigens of rotavirus (VP6) or influenza (NP), or saline. B-cell-deficient females also underwent postconception PRV injection.

RESULTS

Maternal vaccination with PRV improves survival of pups infected with RRV. Serum rotavirus IgG, but not IgA, levels were increased in pups delivered from dams who received RRV, Wa, PRV, or VP6, but in the case of the Wa, PRV, and VP6 groups, these antibodies were not neutralizing. Postconception injection of high-dose PRV did not improve survival of pups born to B-cell-deficient dams.

CONCLUSION

Maternal vaccination against RRV can prevent the rotavirus-induced murine model of BA in newborn mouse pups.

Cost of routine immunization of young children against rotavirus infection with Rotarix versus RotaTeq

Using a probabilistic model of the clinical and economic burden of rotavirus gastroenteritis (RVGE), we estimated the expected impact of vaccinating a US birth cohort with Rotarix in lieu of RotaTeq. Assuming full vaccination of all children, use of Rotarix - rather than RotaTeq - was estimated to reduce the total number of RVGE events by 5% and associated costs by 8%. On an overall basis, Rotarix would reduce costs by $77.2 million (95% CI $71.5-$86.5). Similar reductions with Rotarix were estimated to occur under an assumption of incomplete immunization of children.

Prevention of rotavirus disease: updated guidelines for use of rotavirus vaccine

This statement updates and replaces the 2007 American Academy of Pediatrics statement for prevention of rotavirus gastroenteritis. In February 2006, a live oral human-bovine reassortant rotavirus vaccine (RV5 [RotaTeq]) was licensed as a 3-dose series for use in infants in the United States. The American Academy of Pediatrics recommended routine use of RV5 in infants in the United States. In April 2008, a live, oral, human attenuated rotavirus vaccine (RV1 [Rotarix]) was licensed as a 2-dose series for use in infants in the United States. The American Academy of Pediatrics recommends routine immunization of infants in the United States with rotavirus vaccine. The American Academy of Pediatrics does not express a preference for either RV5 or RV1. RV5 is to be administered orally in a 3-dose series with doses administered at 2, 4, and 6 months of age; RV1 is to be administered orally in a 2-dose series with doses administered at 2 and 4 months of age. The first dose of rotavirus vaccine should be administered from 6 weeks through 14 weeks, 6 days of age. The minimum interval between doses of rotavirus vaccine is 4 weeks. All doses should be administered by 8 months, 0 days of age. Recommendations in this statement also address the maximum ages for doses, contraindications, precautions, and special situations for administration of rotavirus vaccine.

Rotaviruses: from pathogenesis to vaccination

Rotaviruses cause life-threatening gastroenteritis in children worldwide; the enormous disease burden has focused efforts to develop vaccines and led to the discovery of novel mechanisms of gastrointestinal virus pathogenesis and host responses to infection. Two live-attenuated vaccines for gastroenteritis (Rotateq [Merck] and Rotarix) have been licensed in many countries. This review summarizes the latest data on these vaccines, their effectiveness, and challenges to global vaccination. Recent insights into rotavirus pathogenesis also are discussed, including information on extraintestinal infection, viral antagonists of the interferon response, and the first described viral enterotoxin. Rotavirus-induced diarrhea now is considered to be a disease that can be prevented through vaccination, although there are many challenges to achieving global effectiveness. Molecular biology studies of rotavirus replication and pathogenesis have identified unique viral targets that might be useful in developing therapies for immunocompromised children with chronic infections.

Whole genome sequencing of lamb rotavirus and comparative analysis with other mammalian rotaviruses

Rotavirus (RV) epidemiological surveys with molecular analysis of various strains are required for gastroenteritis control and prevention. The lamb rotavirus strain NT, isolated from a diarrhea lamb in China, is considered as a promising vaccine strain. The whole genome of the lamb-NT strain was determined by sequence analysis. Sequence identity and phylogenetic analysis defined the lamb-NT strain as group A, genotype G10P[15]/NSP4[A]/SG1 strain. Comparative genomic analysis of the lamb-NT strain and 17 reference strains reveals that gene reassortments between rotaviruses circulating in different species occurred. Alignment of protein sequences of the genes shows some variations in the important functional regions of VP3 and VP4. These variations are related to host range restriction, virulence, and other potential characters of rotaviruses. Besides, this study also makes a significant foundation for the study of genetic classification, epidemiology, and antigenic diversity of rotaviruses on the molecular level.

Rotavirus disease and prevention through vaccination

Rotavirus is the most common cause of acute infectious gastroenteritis in children and is associated with substantial morbidity in the United States and morbidity and mortality in the developing world. Two orally administered vaccines, a live bovine reassortant vaccine (RV5; licensed in 2006) and a live attenuated human vaccine (RV1; licensed in 2008), are now being used in a universal infant vaccination program in the United States. There is already ecologic evidence and data from post-licensure effectiveness studies that this program will be an unequivocal success in reducing the impact of rotavirus disease. This overview presents the structure, pathogenesis, and mechanisms of natural immunity to rotavirus, key concepts in understanding the rationale behind vaccine-induced protection. The history of rotavirus vaccine development is also included, along with a discussion of the safety, efficacy, and recommended use of the approved vaccines.

Live attenuated human rotavirus vaccine, RIX4414, provides clinical protection in infants against rotavirus strains with and without shared G and P genotypes: integrated analysis of randomized controlled trials

BACKGROUND

: The 2-dose, oral live attenuated human G1P[8] rotavirus vaccine (RIX4414) is highly effective against rotavirus gastroenteritis caused by circulating G1 and non-G1 types. An integrated analysis on vaccine efficacy was undertaken to obtain more precise estimates of the overall protective effect of the RIX4414 vaccine against rotavirus gastroenteritis due to common rotavirus types (G1, G3, G4, G9, P[8]) and less commonly encountered strains such as G2P[4] across heterogenous settings.

METHODS

: The studies used in the integrated analysis were all previously reported randomized, double-blind, placebo-controlled, phase II and III trials with at least 1 report of rotavirus gastroenteritis in the efficacy follow-up period (up to 1 year of age or end of first RV epidemic season after vaccination). The integrated analysis was performed for all circulating rotavirus strains sharing G and/or P genotype and not sharing G or P genotype with the vaccine strain. Vaccine efficacy was estimated as 1 minus rate of rotavirus gastroenteritis relative to placebo, using exact Poisson rate ratio stratified by study.

RESULTS

: The integrated estimates for vaccine efficacy against severe rotavirus gastroenteritis were 87.43% (95% confidence interval [CI]: 78.89-92.86) for G1P[8] strains, 71.42% (95% CI: 20.12-91.11) for G2P[4] strains, 90.19% (95% CI: 55.51-98.94) for G3P[8] strains, 93.37% (95% CI: 51.50-99.85) for G4P[8] strains, and 83.76% (95% CI: 71.18-91.28) for G9P[8] strains. The integrated estimates for vaccine efficacies against rotavirus gastroenteritis of any severity were 82.57% (95% CI: 73.91-88.56) for G1P[8] strains, 81.04% (95% CI: 31.58-95.76) for G2P[4] strains, 87.66% (95% CI: 34.57-98.76) for G3P[8] strains, 84.86% (95% CI: 50.92-96.41) for G4P[8] strains, and 60.64% (95% CI: 38.15-74.96) for G9P[8] strains.

CONCLUSIONS

: Two doses of RIX4414 provide overall good clinical protection against all cases of rotavirus gastroenteritis and comparable, high clinical protection against severe rotavirus gastroenteritis caused by circulating rotavirus strains with and without G and P genotypes shared with the vaccine strain, such as G2P[4].

Rotavirus vaccine RIX4414 (Rotarix): a review of its use in the prevention of rotavirus gastroenteritis

Rotavirus vaccine RIX4414 is an oral vaccine composed of a monovalent, live, attenuated, human rotavirus strain of G1P[8] type. RIX4414 vaccination in infants aged 6-17 weeks at enrolment provided protection against rotavirus gastroenteritis (RVGE) of any severity and high-level protection against severe RVGE requiring hospitalization in large, randomized clinical trials conducted in a wide range of geographic regions. Protective efficacy was evident over the period (2 months) between the first and second doses of vaccine, and the protection afforded by the full two-dose course was sustained for at least 2 years, the limit to which efficacy was assessed. RIX4414 displayed protective efficacy against the common rotavirus G, P[8] types (G1P[8], G3P[8], G4P[8], and G9P[8]) and the fully heterotypic G2P[4] type. RIX4414 did not interfere with other common childhood injectable immunizations when administered concomitantly, suggesting that it should be possible to integrate the vaccine into most routine childhood vaccination schedules, including those still using oral poliovirus vaccine. RIX4414 was generally well tolerated and there was no evidence of an increased risk of intussusception. Although dependent on many factors, including prevalent infecting strains, efficacy rates, and vaccine costs, pharmacoeconomic analyses suggest that mass immunization with RIX4414 would be cost effective in many countries, especially when assessed from the societal perspective. Therefore, rotavirus vaccine RIX4414 offers a highly effective control strategy for reducing the burden of RVGE in infants.

The human rotavirus vaccine RIX4414 in infants: a review of safety and tolerability

BACKGROUND

An oral, live attenuated human rotavirus vaccine, RIX4414 has been developed to prevent rotavirus gastroenteritis. An integrated safety summary of 8 randomized, placebo-controlled, double-blind phase II and III trials of vaccine at potency licensed for use worldwide was performed.

METHODS

Healthy 1- to 18-week-old infants (N = 71209) were enrolled to receive 2 doses of RIX4414/placebo according to 0, 1 or 0, 2 month schedules. Solicited (fever, fussiness/irritability, loss of appetite, vomiting, diarrhea, cough/rhinorrhea) and unsolicited adverse events (AEs) were recorded for 8 days and 31 days, respectively, after each dose. Serious adverse events (SAEs) including intussusception and death were collected throughout the entire study periods. Potential imbalances were defined as the 95% confidence interval (CI) for the relative risk (RR) stratified by trials excluding "1."

RESULTS

Solicited AEs were evaluated in 3286 RIX4414 vaccinees and 2015 placebo recipients. Among solicited AEs, no imbalance was noted between groups. SAEs, including death and intussusception, were evaluated in 36755 RIX4414 and 34454 placebo recipients. Within 31 days after each dose, no imbalances were noted between the groups for all SAEs (RR = 0.9; 95% CI: 0.81, 1.01), deaths (RR = 1.64; 95% CI: 0.92, 3.02), and intussusception (RR 1.23; 95% CI: 0.41, 3.90). SAEs because of gastrointestinal diseases including diarrhea, gastroenteritis (all cause and due to rotavirus), dehydration, and intestinal ileus occurred significantly less often in RIX4414 than placebo recipients.

CONCLUSIONS

Across the phase II and III clinical trials, the reactogenicity and safety profile between RIX4414 and placebo was similar, in particular with no increased risk of intussusception.

Mechanisms of protection against rotavirus infection and disease

Rotavirus is a double-stranded RNA virus composed of 3 protein layers. These layers contain structural proteins (eg, VP4, VP6, and VP7) that are involved in the induction of immunity. Despite extensive research in animal models and humans, the mechanisms and effectors of protection against rotavirus after either natural infection or vaccination remain unclear. Complicating factors include the variety of immunologic responses produced after both natural infection and vaccination, and the fact that animal models do not fully mimic the human immunologic responses, even when inoculated with homologous rotaviruses. Nevertheless, it appears that neutralizing antibodies have a role in protection against rotavirus infection and disease, but that other effectors, such as non-neutralizing antibodies and T cells, have important effector properties as well. These effectors likely have overlapping functions, thus providing enhanced protection. The results of further research to elucidate the immunologic mechanism of protection will provide insight into improving the efficacy of current vaccines.

Burden of acute gastroenteritis hospitalizations and emergency department visits in US children that is potentially preventable by rotavirus vaccination: a probe study using the now-withdrawn rotashield vaccine

BACKGROUND

With the implementation of a new rotavirus immunization program in the United States in 2006, determining the potential health benefits of rotavirus vaccination is important. We estimated the burden of acute gastroenteritis hospitalizations and emergency department visits in US children that are potentially preventable by rotavirus vaccination.

METHODS

We conducted a retrospective cohort analysis of children who in 1998-1999 were eligible to receive a now-withdrawn rotavirus vaccine (RotaShield) and were continuously enrolled in 1 of 6 managed care organizations in the Vaccine Safety Datalink. Estimates of vaccine effectiveness against all-cause gastroenteritis hospitalizations and emergency department visits adjusted according to month of birth, gender, and managed care organizations were calculated as 1 minus the risk ratio of outcomes among children in different dose groups. The burden of acute gastroenteritis prevented by vaccination was compared with the rotavirus burden estimated by 2 previously used indirect methods.

RESULTS

The effectiveness of a full 3-dose RotaShield series over a 1-year follow-up period was 83% against all-cause gastroenteritis hospitalizations and 43% against all-cause gastroenteritis emergency department visits. An increasing number of doses improved the effectiveness in preventing gastroenteritis hospitalizations, but no clear trend was observed between number of doses and effectiveness in prevention of gastroenteritis emergency department visits. The proportion of gastroenteritis hospitalizations and emergency department visits prevented by vaccination was substantially greater than the 48% to 53% of year-round hospitalizations and 33% of emergency department visits estimated to result from rotavirus by indirect methods.

CONCLUSIONS

The withdrawn rotavirus vaccine was highly effective in preventing hospitalizations and emergency department visits for all-cause acute gastroenteritis and the health benefits of vaccination against rotavirus may be greater than previously estimated.

Hospital-based surveillance to estimate the burden of rotavirus gastroenteritis among European children younger than 5 years of age

OBJECTIVES

Rotavirus is the leading cause of acute gastroenteritis requiring hospitalization in young children. Data on the burden of rotavirus gastroenteritis are needed to guide recommendations for rotavirus vaccine use. This study was undertaken to estimate the burden of rotavirus gastroenteritis in European children <5 years of age.

METHODS

This prospective, study was conducted in 12 hospitals in France, Germany, Italy, Spain, and the United Kingdom. A sample of all children aged <5 years presenting to emergency departments or hospitalized because of community-acquired acute gastroenteritis was enrolled for parental interview and stool collection. Acute gastroenteritis was defined as diarrhea (>/=3 loose stools per 24 hours) for <14 days. Rotavirus was detected by enzyme-linked immunosorbent assay and typed by reverse-transcriptase polymerase chain reaction.

RESULTS

Between February 2005 and August 2006, 3734 children with community-acquired acute gastroenteritis were recruited and retained for analysis (55.9% via the emergency department, 41.8% hospitalized). Of the 2928 community-acquired acute gastroenteritis cases for which stool samples were available, 43.4% were rotavirus-positive by enzyme-linked immunosorbent assay (32.8% emergency department, 56.2% hospitalized). Of these rotavirus gastroenteritis cases 80.9% occurred in children aged <2 years and 15.9% among infants aged <6 months. Acute gastroenteritis was more severe in rotavirus-positive subjects (Vesikari score >/= 11 in 53.3% compared with 31.0% of rotavirus-negative subjects). All 1271 rotavirus-positive strains were genotyped (G1P[8]: 40.3%; G9P[8]: 31.2%; G4P[8]: 13.5%; G3P[8]: 7.1%).

CONCLUSIONS

Rotavirus gastroenteritis places high demands on European health care systems, accounting for 56.2% of hospitalizations and 32.8% of emergency department visits because of community-acquired acute gastroenteritis in children aged <5 years. Most community-acquired rotavirus gastroenteritis occurs in children aged <2 years, and a high proportion occurs in infants aged <6 months. Cases were also observed among very young infants <2 months of age. Rotavirus vaccination is expected to have a major impact in reducing morbidity and the pressure on hospital services in Europe.

Cost-effectiveness of childhood rotavirus vaccination in Taiwan

OBJECTIVE

Rotavirus is the most common cause of severe diarrhea in children. Two rotavirus vaccines (RotaTeq and Rotarix) have been licensed in Taiwan. We have investigated whether routine infant immunization with either vaccine could be cost-effective in Taiwan.

METHODS

We modeled specific disease outcomes including hospitalization, emergency department visits, hospital outpatient visits, physician office visits, and death. Cost-effectiveness was analyzed from the perspectives of the health care system and society. A decision tree was used to estimate the disease burden and costs based on data from published and unpublished sources.

RESULTS

A routine rotavirus immunization program would prevent 146,470 (Rotarix) or 149,937 (RotaTeq) cases of rotavirus diarrhea per year, and would prevent 21,106 (Rotarix) and 23,057 (RotaTeq) serious cases (hospitalizations, emergency department visits, and death). At US$80 per dose for the Rotarix vaccine, the program would cost US$32.7 million, provided an increasing cost offset of US$19.8 million to the health care system with $135 per case averted. Threshold analysis identified a break-even price per dose of US$27 from the health care system perspective and US$41 from a societal perspective. At US$60.0 per dose of RotaTeq vaccine, the program would cost US$35.4 million and provide an increasing cost offset of US$22.5 million to the health care system, or US$150 per case averted. Threshold analysis identified a break-even price per dose of US$20.0 from the health care system perspective and $29 from the societal perspective. Greater costs of hospitalization and lower vaccine price could increase cost-effectiveness.

CONCLUSIONS

Despite a higher burden of serious rotavirus disease than estimated previously, routine rotavirus vaccination would unlikely be cost-saving in Taiwan at present unless the price fell to US$41 (Rotarix) or US$29 (RotaTeq) per dose from societal perspective, respectively. Nonetheless, rotavirus immunization could reduce the substantial burden of short-term morbidity due to rotavirus.

Rotarix: a rotavirus vaccine for the world

Single rotavirus infections have been reported to protect humans against subsequent illnesses caused by both homotypic and heterotypic rotaviruses. On the basis of these observations, a G1P[8] strain of human rotavirus named 89-12 was attenuated by multiple passages in cell culture and was developed into a vaccine candidate (herein referred to as the RIX4414 vaccine). This vaccine is currently licensed in >100 countries worldwide, many of which have a universal recommendation for all infants. The US Food and Drug Administration approved the RIX4414 vaccine for use in the United States in April 2008. This vaccine has been found to provide a reduction in the incidence of severe rotavirus disease of >80% in all trials including a developing country. No increased risk of intussusception has been associated with this vaccine, nor has the vaccine been found to interfere with responses to other routine immunizations. This article describes the history of the development of the RIX4414 vaccine.

Rotavirus vaccines

Two live attenuated oral rotavirus vaccines were licensed in 2006 for prevention of severe acute gastroenteritis in children: Rotarix (GSK), a human rotavirus vaccine with G1P[8] serotype characteristics and RotaTeq (Merck), a bovine-human reassortant vaccine expressing human G1-4 and P[8] antigens. In prelicensure trials both vaccines showed high efficacy against severe RV gastroenteritis, low reactogenicity and no increased risk for intussusception (IS) (Ruiz-Palacios et al., 2006; Vesikari et al., 2006). Both vaccines have now been distributed in millions of doses. Post-marketing data have not shown any gross signal for IS with either vaccine, but further data and analyses are required for final conclusion on safety of these vaccines.

Rotaviruses and rotavirus vaccines

BACKGROUND

Rotaviruses (RVs) are an important cause of acute gastroenteritis in infants and young children worldwide, resulting in more than 600 000 deaths per annum, mainly in developing countries. Since the 1980s, there has been intensive research on the development of RV vaccine candidates, and since 2006 two vaccines have been licensed in many countries.

SOURCES OF DATA

The scientific literature since the 1970s has been consulted, and the results of original research carried out in authors' laboratories were used.

AREAS OF AGREEMENT

There are firmly established data on virus particle structure, genome composition, gene-protein assignment, protein-function assignment (incomplete), virus classification, the mechanisms of several steps of the replication cycle (adsorption, primary transcription, virus maturation-all partial), several mechanisms of pathogenesis, aspects of the immune response, diagnosis, illness and treatment, epidemiology and vaccine development.

AREAS OF CONTROVERSY

Research on the following areas is still in full flux and in part not generally accepted: several steps of the replication cycle (mechanism of viral entry into host cells, mechanisms of packaging and reassortment of viral RNAs, morphogenesis of subviral particles in viroplasms and maturation of virus particles in the rough endoplasmic reticulum (RER) with temporary acquisition and subsequent loss of an envelope), the true correlates of protection and the long-term effectiveness of RV vaccines. GROWING RESEARCH: Recently, a system that allows carrying out reverse genetics with some of the RV genes has been established which, however, has limitations. There is intensive research ongoing, which is trying to develop better and universally applicable reverse genetics systems. There is broad research on the molecular mechanisms of the immune response and on which immunological parameter correlates best with lasting protection from severe RV disease. Research into other than live attenuated vaccines is growing.

AREAS TIMELY FOR DEVELOPING RESEARCH

The establishment of better reverse genetics systems for RVs is the most important research goal for both the understanding of the molecular biology of RVs and the development of new and safe RV vaccines. The black boxes of our knowledge on aspects of RV replication (RNA packaging, RNA replication, control of reassortment and functions of the non-structural RV proteins) are under intensive research.

Cost-Effectiveness of Rotavirus Vaccination: Exploring Caregiver(s) and ``No Medical Care'' Disease Impact in Belgium

Aim . To estimate the cost-effectiveness of universal childhood rotavirus vaccination in Belgium, taking into account the impact of caregiver burden and the burden of sick children for whom no medical care is sought (``no medical care''). Methods . A cohort of newborns is modeled in relation to costs and health outcomes for rotavirus disease, distinguishing episodes leading to consultations, hospitalizations, and deaths from no medical care episodes. Fully funded universal vaccination is compared with no vaccination as well as with the current situation in Belgium, whereby the 2-dose Rotarix or the 3-dose RotaTeq vaccine can be bought at market prices, which are partially reimbursed. Results . Compared with no vaccination, fully funded universal rotavirus vaccination would cost 51,030 per quality-adjusted life year (QALY) gained with Rotarix and 65,767 with RotaTeq (for society, 7572 and 30,227 per QALY, respectively). However, there is considerable uncertainty due to some analytical choices: the proportion of simulations with an acceptable incremental cost-effectiveness ratio (given a willingness to pay 50,000 for an additional QALY), increases from 2%/0.6% (Rotarix/RotaTeq) to 86%/59% when considering no medical care, and including 2 caregivers to estimate QALY loss instead of zero. Uncertainty is greater still under the societal than under the health care payer perspective. Conclusion . For the Belgian health care payer, at current vaccine prices, universal childhood rotavirus vaccination is unlikely to be judged cost-effective versus no vaccination but would be a more efficient and equitable choice than continuing with current practice.

Active, population-based surveillance for severe rotavirus gastroenteritis in children in the United States

OBJECTIVES

Routine vaccination of US infants against rotavirus was implemented in 2006, prompting the Centers for Disease Control and Prevention New Vaccine Surveillance Network to begin population-based acute gastroenteritis surveillance among US children<3 years of age. This surveillance system establishes baseline estimates of rotavirus disease burden and allows for the prospective monitoring of rotavirus vaccination impact.

METHODS

Eligible children with acute gastroenteritis (>or=3 episodes of diarrhea and/or any vomiting in a 24-hour period) who were hospitalized, were seen in emergency departments, or visited selected outpatient clinics in 3 US counties during the period of January through June 2006 were enrolled. Epidemiological and clinical information was obtained through parental interview and medical chart review, and stool specimens were tested for rotavirus with enzyme immunoassays. Rotavirus-positive specimens were genotyped by using reverse transcription-polymerase chain reaction assays.

RESULTS

Stool specimens were collected from 516 of the 739 enrolled children with acute gastroenteritis (181 inpatient, 201 emergency department, and 134 outpatient) and 44% tested positive for rotavirus (227 of 516 specimens). The most common strain was P[8]G1 (84%), followed by P[4]G2 (5%) and P[6]G12 (4%). None of the 516 children had received rotavirus vaccine. The rotavirus detection rate was 50% for hospitalized acute gastroenteritis cases, 50% for emergency department visits, and 27% for outpatient visits. Rotavirus-related acute gastroenteritis cases were more likely than non-rotavirus-related acute gastroenteritis cases to present with vomiting, diarrhea, fever, and lethargy. Directly calculated, population-based rates for rotavirus hospitalizations and emergency department visits were 22.5 hospitalizations and 301.0 emergency department visits per 10 000 children<3 years of age, respectively. A sentinel outpatient clinic visit rate of 311.9 outpatient visits per 10,000 children<3 years of age was observed.

CONCLUSIONS

Population-based, laboratory-confirmed rotavirus surveillance in the final rotavirus season before implementation of the US rotavirus vaccine program indicated a considerable burden of disease on the US health care system.

The health and economic burden of rotavirus disease in Belgium

For health economic evaluations of rotavirus vaccination, estimates of the health and cost burden of rotavirus are required. Due to differences in health care systems and surveillance organisations, this is difficult to achieve by imputing estimates from one country to others. This study aimed to estimate the burden of rotavirus disease in Belgium. In children younger than 7 years of age, rotavirus is predicted to account annually for about 5,600 hospitalisations (676:100,000 children); 26,800 outpatient, general practitioner and paediatrician visits; and about 44,600 episodes for which no medical care is sought. This burden is estimated to represent direct costs of 7.7 million Euro and indirect costs of 12.8 million Euro. Rotavirus disease causes a substantial health and economic burden in Belgium.

Structured surveillance of infectious intestinal disease in pre-school children in the community: ‘The Nappy Study’

The incidence and causes of infectious intestinal disease (IID) in children aged <5 years presenting to general practitioners (GPs) were estimated. During a 12-month period, soiled nappies were collected from children presenting with symptoms suggestive of IID in a network of 65 GPs located across England. Molecular methods were used to detect a range of enteric pathogens including viruses, bacteria and parasites. Genotyping was performed on rotavirus and norovirus isolates. A total of 583 nappies were collected from 554 children; a pathogen was detected in 361 (62%) specimens. In the 43 practices 1584 new episodes of IID were recorded in a population averaging 19774; the specimen capture rate was 28%. IID incidence peaked during March and April. Norovirus (24·5%), rotavirus (19·0%) and sapovirus (12·7%) were most commonly detected, and mixed infections were detected in 11·7% of cases. Strain characterization revealed G1P[8] (65·8%), G4P[4] (8·1%) and G9P[8] (8·1%) as the most common rotavirus genotypes, similar to the UK national distribution. GII-3 (42·9%) and GII-4 (39·7%) were the most common norovirus genotypes; this was significantly different (P<0·005) to the national distribution.

Coadministration of RIX4414 oral human rotavirus vaccine does not impact the immune response to antigens contained in routine infant vaccines in the United States

OBJECTIVE

This study was conducted to confirm the absence of immune interference of 2 doses of RIX4414 (Rotarix) on routine infant vaccinations in the United States.

STUDY DESIGN

A total of 484 healthy infants aged 6 to 12 weeks were randomly assigned to 1 of 2 groups to receive 3 doses of Pediarix (combined diphtheria-tetanus-acellular pertussis-hepatitis B-poliovirus vaccine [DTaP-HBV-IPV]), Prevnar (7-valent pneumococcal conjugate vaccine [PCV7]), and ActHIB (Haemophilus influenzae type b conjugate vaccine [Hib]) at 2, 4, and 6 months of age with RIX4414 either coadministered at 2 and 4 months (Co-ad) or administered separately at 3 and 5 months (Sep-ad). Serum antibodies were measured 1 month after dose 3 of the DTaP-HBV-IPV, PCV7, and Hib vaccines.

RESULTS

Antibody responses to all antigens were similar in infants in both the Co-ad and Sep-ad groups. Seroprotective antibody concentrations against diphtheria, tetanus, hepatitis B, and poliovirus types 1, 2, and 3 were achieved by >or=97.9% of the infants in both groups. Antipolyribosyl ribitol phosphate antibody levels of >or=1.0 microg/mL were achieved by 88.3% to 89.4% of infants in both groups. In both groups, >or=97.8% of the infants were seropositive for antipertussis antibodies and the 7 pneumococcal serotypes. Predefined criteria for noninferiority between groups were reached for all antigens.

CONCLUSIONS

Two doses of RIX4414 coadministered with routine infant vaccines as recommended in the United States (DTaP-HBV-IPV, PCV7, and Hib) did not impair the immune response to any of the coadministered antigens.

Two out of the 11 genes of an unusual human G6P[6] rotavirus isolate are of bovine origin

In 2003, we described the first human G6P[6] rotavirus strain (B1711). To investigate further the molecular origin of this strain and to determine the possible reassortments leading to this new gene constellation, the complete genome of strain B1711 was sequenced. SimPlot analyses were conducted to compare strain B1711 with other known rotavirus gene segments, and phylogenetic dendrograms were constructed to analyse the origin of the eleven genome segments of strain B1711. Our analysis indicated that strain B1711 acquired its VP1-, VP2-, VP4-, VP6- and NSP1–5-encoding gene segments from human DS-1-like P[6] rotavirus strains, and its VP3 and VP7 gene segments from a bovine rotavirus strain through reassortment. The introduction of animal–human reassortant strains, which might arise in either of the hosts, into the human rotavirus population is an important mechanism for the generation of rotavirus diversity, and might be a challenge for the current rotavirus vaccines and vaccines under development.

Vaccination in acute childhood viral gastroenteritis

Acute viral gastroenteritis is, after respiratory tract infections, the second most common cause of childhood morbidity, hospitalizations and deaths. Amidst a large number of enteric viruses, rotavirus (RV) and norovirus (NV) have been presently recognized as the most important. RV is considered a single, major cause of severe acute diarrhea and the greatest cause of diarrhea-related deaths among children, whereas NV is a major cause of outbreaks, including those in medical facilities. Since improvements in sanitation and hygiene standards have demonstrated little impact on morbidity rate, vaccination early in life appears to be an effective tool to prevent this common disease. Currently, two efficacious oral vaccines are available in several countries in the world. The key challenge is their relatively high price, particularly for the poorest nations, where the need for routine vaccination is of great importance.

Efficacy and safety of an oral live attenuated human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in Latin American infants: a randomised, double-blind, placebo-controlled phase III study

BACKGROUND

Peak incidence of rotavirus gastroenteritis is seen in infants between 6 and 24 months of age. We therefore aimed to assess the 2-year efficacy and safety of an oral live attenuated human rotavirus vaccine for prevention of severe gastroenteritis in infants.

METHODS

15 183 healthy infants aged 6-13 weeks from ten Latin American countries randomly assigned in a 1 to 1 ratio to receive two oral doses of RIX4414 or placebo at about 2 and 4 months of age in a double-blind, placebo-controlled phase III study were followed up until about 2 years of age. Primary endpoint was vaccine efficacy from 2 weeks after dose two until 1 year of age. Treatment allocation was concealed from investigators and parents of participating infants. Efficacy follow-up for gastroenteritis episodes was undertaken from 2 weeks after dose two until about 2 years of age. Analysis was according to protocol. This study is registered with ClinicalTrials.gov, number NCT00140673 (eTrack444563-023).

FINDINGS

897 infants were excluded from the according-to-protocol analysis. Fewer cases (p<0.0001) of severe rotavirus gastroenteritis were recorded for the combined 2-year period in the RIX4414 group (32 [0.4%] of 7205; 95% CI 0.3-0.6) than in the placebo group (161 [2.3%] of 7081; 1.9-2.6), resulting in a vaccine efficacy of 80.5% (71.3-87.1) to 82.1% (64.6-91.9) against wild-type G1, 77.5% (64.7-86.2) against pooled non-G1 strains, and 80.5% (67.9-88.8) against pooled non-G1 P[8] strains. Vaccine efficacy for hospital admission for rotavirus gastroenteritis was 83.0% (73.1-89.7) and for admission for diarrhoea of any cause was 39.3% (29.1-48.1). No cases of intussusception were reported during the second year of follow-up.

INTERPRETATION

Two doses of RIX4414 were effective against severe rotavirus gastroenteritis during the first 2 years of life in a Latin American setting. Inclusion of RIX4414 in routine paediatric immunisations should reduce the burden of rotavirus gastroenteritis worldwide.

Cost-effectiveness analysis of vaccination against rotavirus with RIX4414 in France

BACKGROUND

It is estimated that annually 300 000 cases of rotavirus-induced gastroenteritis (RVGE) occur in children aged up to 5 years in France. A two-dose vaccine against rotavirus infection (RIX4414; Rotarix, GlaxoSmithKline), has been shown to be highly effective against severe RVGE.

OBJECTIVE

This study evaluated the cost effectiveness of general vaccination against rotavirus using RIX4414 in France.

METHODS

A Markov model simulated RVGE events and the associated outcomes and costs relating to general vaccination of infants against rotavirus infection using RIX4414 (Rotarix) in a birth cohort of children aged up to 5 years in France with a combined adjustment for age distribution with the seasonality of the infection. Costs and outcomes were estimated from a limited societal perspective, including direct medical costs paid out of pocket or by third-party payers, as well as the proportion of direct medical costs reimbursed by the health authorities. Indirect costs were not included in the base-case analysis. The primary outcome measure was the incremental cost per QALY.

RESULTS

Vaccination with RIX4414 incurred an incremental cost of 44 583 Euro per QALY at a public price of 57 Euro per vaccine dose. Univariate sensitivity analyses showed that the parameters with the largest influence on the results were the transition probabilities of severe diarrhoea, seeking medical advice and emergency visits, utility scores of diarrhoea (mild) in children and infants, and the discount rate for benefits. Probabilistic multivariate sensitivity analysis confirmed these results. The acceptability curve indicated that 94% of the results were under an informal threshold of 50 000 Euro per QALY. Comparing our results with those of a recently published study using pooled data for two rotavirus vaccine products in France, the main differences are explained by differences in model structure and in data input values. They include a different age distribution of the infection, shorter duration of the at-risk period (3 years instead of 5 years), different vaccine efficacy, different unit cost data, different disease duration, and different disutility values for the health states in the model. There is a need for agreed standards to improve comparability of results from different studies.

CONCLUSIONS

The results demonstrate that a generalized vaccination strategy with RIX4414 would be cost effective in France from a limited societal perspective, depending on the baseline assumptions for disease progression and on utility scores selected.

Estimating utility scores in young children with acute rotavirus gastroenteritis in the UK

OBJECTIVE

To estimate utility scores for different severities of acute rotavirus gastroenteritis in children aged<5 years in the UK.

METHODS

UK general practitioners (n=25) and paediatricians (n=25) rated four different health state descriptions of acute rotavirus gastroenteritis using the EuroQol (EQ-5D) questionnaire for children aged<18 months and 18 months to 5 years. EQ-5D scores were modified to account for limited self-care and mobility, and converted into utility values using the standard algorithm using UK data.

RESULTS

General practitioners rated the mean utility for primary care cases at 0.781 (standard deviation (SD) 0.263) and 0.688 (SD 0.345) for the younger and older age groups, respectively. For hospitalised cases the corresponding scores were 0.425 (SD 0.243) and 0.200 (sd 0.386). Paediatricians rated the mean utility for hospitalised severe cases at 0.595 (SD 0.171) and 0.634 (SD 0.217) in the younger and older groups, respectively, and for hospitalised very severe cases at 0.256 (SD 0.251) and 0.077 (SD 0.340), respectively. In all cases, the utility differences between the health states were statistically significant (p<0.0001).

CONCLUSIONS

Acute rotavirus gastroenteritis substantially impairs quality of life in children aged<5 years as rated by health professionals. This study provides useful quantitative utility estimates for economic evaluations.

Rotavirus vaccines: an overview

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. Vaccination is the only control measure likely to have a significant impact on the incidence of severe dehydrating rotavirus disease. In 1999, a highly efficacious rotavirus vaccine licensed in the United States, RotaShield, was withdrawn from the market after 14 months because of its association with intussusception. Two new live, oral, attenuated rotavirus vaccines were licensed in 2006: the pentavalent bovine-human reassortant vaccine (RotaTeq) and the monovalent human rotavirus vaccine (Rotarix). Both vaccines have demonstrated very good safety and efficacy profiles in large clinical trials in western industrialized countries and in Latin America. Careful surveillance has not revealed any increased risk of intussusception in the vaccinated groups with either vaccine. The new rotavirus vaccines are now introduced for routine use in a number of industrialized and developing countries. These new safe and effective rotavirus vaccines offer the best hope of reducing the toll of acute rotavirus gastroenteritis in both developed and developing countries.