Effect of rhesus rotavirus vaccine on enteric adenovirus--associated diarrhea in children

Effect of rotavirus vaccine implementation on the prevalence of coinfections with enteric viruses in Norway

Acute gastroenteritis (AGE) is a common illness in both adults and children worldwide and is caused by several microorganisms including viruses, bacteria, and parasites. Rotavirus (RV), which is the main cause of AGE, can occur as a mixed infection with other viruses. The aim of this study is to assess the molecular epidemiology of viral enteric viruses and assess RV coinfections with other enteric viruses and their influence on disease severity before and after RV vaccine introduction in children under 5 years of age. A total of 600 samples collected from children hospitalized for AGE in five large hospitals in Norway, and were analyzed for viral gastroenteritis agents by enzyme immunoassay and quantitative real-time polymerase chain reaction (qRT-PCR). Positive results confirmed either by Sanger sequencing or genotyped by multiplex semi-nested RT-PCR. In total, 243 of the 300 (81%) samples, collected from the prevaccine cohort, were positive for at least one of the four viruses tested in this study. RV was most frequently identified in 82.6% of the samples. In the postvaccine cohort, 114 of the 300 (38%) samples were positive for at least one of the viruses tested. RV found in 36.5% of the samples. Coinfections found less frequently in the postvaccine cohort. Among circulating enteric viruses in Norway, RV is the most important cause of viral gastrointestinal infection. As expected, there were fewer RV positive and fewer coinfections after RV vaccine implementation. The results provide valuable data that can aid in further evaluation of the vaccine impact.

The effectiveness of rotavirus vaccine in preventing acute gastroenteritis during rotavirus seasons among Polish children

INTRODUCTION

Rotavirus is the main etiological cause of intestinal infections in children. Voluntary rotavirus vaccines were included in the Polish vaccination schedule in 2007. The aim of this study was to assess the effectiveness of a completed rotavirus vaccination course in preventing acute gastroenteritis in Polish infants during their first five years of life.

MATERIAL AND METHODS

This was a retrospective cohort study conducted in Lesser Poland (Malopolska Province). The sample population included a group of 303 children who received the completed rotavirus vaccination course and 303 children not vaccinated against rotavirus. The date of the child's acute gastroenteritis diagnosis and his or her vaccination history were extracted from the physicians' records. Each kind of diagnosed acute gastroenteritis during winter-spring rotavirus seasons was treated as the endpoint. The relative risk of having gastrointestinal infection was assessed using the hazard ratio from the Cox proportional hazards regression model.

RESULTS

In the examined group, 96 (15.8%) children had winter-spring gastrointestinal infections. In the non-vaccinated children, the cumulative incidence of these infections in the first 5 years of life was 20.8%, whereas in the children vaccinated with Rotarix it was only 10.9%. Those who were vaccinated with Rotarix had a 44% reduction in the risk of a winter-spring acute gastroenteritis infection compared to those not vaccinated with Rotarix (p = 0.005). Birth weight less than 2500 g increased the risk of the infection twofold and also reached statistical significance (p = 0.044).

CONCLUSIONS

The results showed that Rotarix is effective in preventing acute gastroenteritis in Polish children during rotavirus seasons.

Hospital bed occupancy for rotavirus and all cause acute gastroenteritis in two Finnish hospitals before and after the implementation of the national rotavirus vaccination program with RotaTeq®

Background

Vaccination-impact studies of the live-attenuated pentavalent oral vaccine Rotateq® have demonstrated that the burden of rotavirus gastroenteritis has been reduced significantly after the introduction of RotaTeq® vaccination, but less is known about the benefit of this vaccination on hospital overcrowding.

Methods

As part of an observational surveillance conducted during the RV seasons 2000/2001 to 2011/2012, we analysed hospital discharge data collected retrospectively from two Finnish hospitals (Oulu and Tampere), concerning ICD 10 codes A00-09 (acute gastroenteritis, AGE) and A08.0 (rotaviral acute gastroenteritis RV AGE). We estimated the reduction in the number of beds occupied and analysed the bed occupancy rate, for RV AGE and all cause AGE, among 0–16 year-old children, before and after the implementation of the RV immunisation program.

Results

The rate of bed days occupied for RV AGE was reduced by 86% (95% CI 66%-94%) in Tampere and 79% (95% CI 47%-92%) in Oulu after RV vaccination implementation. For all cause AGE, reduction was 50% (95% CI 29% to 65%) in Tampere and 70% (95% CI 58% to 79%) in Oulu. Results were similar among 0–2 year-old children. This effect was also observed on overcrowding in both hospitals, with a bed occupancy rate for all cause AGE >25% in only 1% of the time in Tampere and 9% in Oulu after the implementation of the immunisation program, compared to 13% and 48% in the pre-vaccination period respectively. After extrapolation to the whole country, the annual number of prevented hospitalizations for all cause AGE in the post-vaccination period in Finland was estimated at 1,646 and 2,303 admissions for 0–2 and 0–16 year-old children respectively.

Conclusions

This study demonstrated that universal RV vaccination is associated with a clear decrease in the number of bed days and occupancy rates for RV AGE and all cause AGE. Positive consequences include increase in quality of care and a better healthcare management during winter epidemics.

Predominance of norovirus and sapovirus in Nicaragua after implementation of universal rotavirus vaccination

Background

Despite significant reduction of rotavirus (RV) infections following implementation of RotaTeq vaccination in Nicaragua, a large burden of patients with diarrhea persists.

Methods

We conducted a community- and hospital-based study of the burden of RV, norovirus (NV) and sapovirus (SV) infections as cause of sporadic acute gastroenteritis (GE) among 330 children ≤ 5 years of age between September 2009 and October 2010 in two major cities of Nicaragua with a RotaTeq coverage rate of 95%.

Results

We found that NV, SV and RV infections altogether accounted for 45% of cases of GE. Notably, NV was found in 24% (79/330) of the children, followed by SV (17%, 57/330) and RV (8%, 25/330). The detection rate in the hospital setting was 27%, 15% and 14% for NV, SV and RV respectively, whereas in the community setting the detection rate of RV was < 1%. Among each of the investigated viruses one particular genogroup or genotype was dominant; GII.4 (82%) for NV, GI (46%) for SV and G1P[8] (64%) in RV. These variants were also found in higher proportions in the hospital setting compared to the community setting. The GII.4.2006 Minerva strain circulating globally since 2006 was the most common among genotyped NV in this study, with the GII.4-2010 New Orleans emerging in 2010.

Conclusions

This study shows that NV has become the leading viral cause of gastroenteritis at hospital and community settings in Nicaragua after implementation of RV vaccination.

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.

Major reduction of rotavirus, but not norovirus, gastroenteritis in children seen in hospital after the introduction of RotaTeq vaccine into the National Immunization Programme in Finland

Universal rotavirus (RV) vaccination is expected to reduce hospitalizations for acute gastroenteritis (GE) of children by eliminating most of severe RVGE, but it does not have any effect on norovirus (NV), the second most common causative agent of GE in children. After the introduction of the RV vaccine into the National Immunization Programme (NIP) of Finland in 2009, we conducted a prospective 2-year survey of GE in children seen in Tampere University Hospital either as outpatients or inpatients and compared the results with a similar 2-year survey conducted prior to NIP in the years 2006-2008. Compared with the pre-NIP 2-year period, in 2009-2011, hospitalizations for RVGE were reduced by 76 % and outpatient clinic visits were reduced by 81 %. NVGE showed a slight decreasing trend and accounted for 34 % of all cases of GE seen in hospital in pursuance of RVGE having decreased to 26 % (down from 52 %). In cases admitted to the hospital ward, RV accounted for 28 % and NV accounted for 37 %.The impact of RV vaccination was reflected as a 57 % decrease in all hospital admissions and 62 % decrease in all outpatient clinic visits for GE of any cause.

CONCLUSION

RV vaccination in NIP has led to a major reduction of hospital admissions and clinic visits due to RVGE, but has had no effect on NVGE. After 2 years of NIP, NV has become the leading cause of acute GE in children seen in hospital.

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.

Rotavirus vaccine for preventing diarrhoea

BACKGROUND

Rotaviruses cause viral gastroenteritis and result in more deaths from diarrhoea in children under 5 years of age than any other single agent, particularly in low- and middle-income countries.

OBJECTIVES

To assess rotavirus vaccines in relation to preventing rotavirus diarrhoea, death, and adverse events.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group's trial register (October 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October 2003), EMBASE (January 1980 to October 2003), LILACS (1982 to October 2003), Biological Abstracts (January 1982 to October 2003), reference lists of articles, and contacted researchers and rotavirus vaccine manufacturers.

SELECTION CRITERIA

Randomized controlled trials comparing rotavirus vaccines to placebo, no intervention, or other rotavirus vaccines in children and adults.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial methodological quality, and contacted trial authors for additional information.

MAIN RESULTS

Sixty-four trials provided information on efficacy and safety of three main types of rotavirus vaccine (bovine, human, and rhesus) for 21,070 children. Different levels of efficacy were demonstrated with different vaccines varying from 22 to 89% to prevent one episode of rotavirus diarrhoea, 11 to 44% to prevent one episode of all-cause diarrhoea, and 43 to 90% to prevent one episode of severe rotavirus diarrhoea. Rhesus vaccine demonstrated a similar efficacy against one episode of rotavirus diarrhoea (37 and 44% respectively), and one episode of all-cause diarrhoea (around 15%) for trials performed in high and middle-income countries. Results on mortality and safety of the vaccines were scarce and incomplete. We noticed important heterogeneity among the pooled studies and were unable to discard a biased estimation of effect.

REVIEWER'S CONCLUSIONS

Current evidence shows that rhesus rotavirus vaccines (particularly RRV-TV) and the human rotavirus vaccine 89-12 are efficacious in preventing diarrhoea caused by rotavirus and all-cause diarrhoea. Evidence about safety, and about mortality or prevention of severe outcomes, is scarce and inconclusive. Bovine rotavirus vaccines were also efficacious, but safety data are not available. Trials of new rotavirus vaccines will hopefully improve the evidence base. Randomized controlled trials should be performed simultaneously in high-, middle-, and low-income countries.

Viral causes of diarrhea

Viruses are important causes of diarrhea. In healthy adults, the main clinical manifestation is acute, self-limited gastroenteritis. Advances in molecular diagnostics have shown that epidemics of acute gastroenteritis most frequently are due to caliciviruses spread through contaminated food or through person-to-person contact. Application of similar technology is needed to make a definitive statement about the role of such candidate viruses as rotavirus, astrovirus, and adenovirus as the cause of nonepidemic acute gastroenteritis in adults. Rarely a previously healthy adult gets acute CMV colitis. CMV and EBV mainly cause diarrhea in immunocompromised patients, however. Advances in prophylaxis and treatment have reduced the frequency and severity of these diseases. Acute infantile gastroenteritis is caused by rotavirus, calcivirus, astrovirus, and adenovirus. These viral diseases of the gut are seen by the physician as routine and rare clinical problems.

Effect of rotavirus vaccine on Sapporo virus gastroenteritis in Finnish infants

BACKGROUND

Sapporo-like viruses (SLVs) occur worldwide, but there is limited information about the SLV-associated gastroenteritis outside Japan.

METHODS

Stool specimens from 1,432 episodes of gastroenteritis that occurred in children between 2 months and 2 years of age during a rotavirus vaccine trial (776 episodes in placebo-vaccinated and 656 in rotavirus-vaccinated infants) were examined for SLVs using a reverse transcription-PCR assay. The reverse transcription-PCR took advantage of new primers specific for Sapporo virus genetic clusters I, II and III; SV/SV82 (SV/Sapporo virus 82); SV/Lond92 (SV/ London 92); and SV/PV (Parkville virus).

RESULTS

SLVs were detected in association with 132 (9.2%) of all episodes; in 80 (5.6%) episodes SLV was the only gastroenteritis virus detected. The epidemic season of SLVs peaked from March to May concurrently with rotaviruses and astroviruses and overlapping withNorwalk-like viruses. Clinically SLV gastroenteritis was characterized by a mild diarrheal disease, being sharply different from the Norwalk-like virus-associated "winter vomiting disease." Rotavirus vaccination did not have any effect on the number of SLV episodes, but the intensity and duration of SLV-associated diarrhea were reduced in rotavirus-vaccinated children compared with placebo-vaccinated children (P = 0.0008).

CONCLUSIONS

SLVs are common causative agents of acute gastroenteritis in young Finnish children. SLV disease is characterized by diarrhea, which is usually mild but can be severe. By an unknown mechanism rotavirus vaccine seems to reduce the severity of SLV-associated diarrhea.

Human caliciviruses in acute gastroenteritis of young children in the community

Episodes of acute gastroenteritis in prospectively followed children between 2 months and 2 years of age were examined for rotaviruses, enteric adenoviruses, astroviruses, and human caliciviruses, including both Norwalk-like viruses (NLVs) and Sapporo-like viruses (SLVs), using PCR and reverse transcription (RT)-PCR assays. A virus was identified in 60% (502/832) of all episodes and in 85% of the moderately severe or severe episodes. Human caliciviruses were as common as rotaviruses, both being detected in 29% of the cases. NLVs accounted for a 20% etiologic share of all cases; the clinical picture was a moderately severe disease with vomiting as a predominant symptom. SLVs were detected in 9% of the cases, the clinical picture being a mild diarrheal disease. Astroviruses were found in 10% and enteric adenoviruses in 6% of the cases. Diagnosis with PCR and RT-PCR methods increases the detection of all gastroenteritis viruses, particularly human caliciviruses. As a group, human caliciviruses are common causative agents of gastroenteritis in children <2 years of age in Finland, and, of these, NLVs cause more severe disease than SLVs.