The first oral rotavirus vaccine, 1998-1999: estimates of uptake from the National Immunization Survey

Factors Associated With Rotavirus Vaccine Coverage

BACKGROUND

Rotavirus vaccines (RVVs) were included in the US immunization program in 2006 and are coadministered with the diphtheria-tetanus-acellular pertussis (DTaP) vaccine, yet their coverage lags behind DTaP. We assessed timing, initiation, and completion of the RVV series among children enrolled in active gastroenteritis surveillance at 7 US medical institutions during 2014-2016.

METHODS

We compared coverage and timing of each vaccine series and analyzed characteristics associated with RVV initiation and completion. We report odds ratios (ORs) and 95% confidence intervals (CIs) from multivariable logistic regression models.

RESULTS

We enrolled 10 603 children. In 2015, ≥1 dose coverage was 91% for RVV and 97% for DTaP. Seven percent of children received their first DTaP vaccine at age ≥15 weeks versus 4% for RVV (P ≤ .001). Recent birth years (2013-2016) were associated with higher odds of RVV initiation (OR = 5.72; 95% CI 4.43-7.39), whereas preterm birth (OR = 0.32; 95% CI 0.24-0.41), older age at DTaP initiation (OR 0.85; 95% CI 0.80-0.91), income between $50 000 and $100 000 (OR = 0.56; 95% CI 0.40-0.78), and higher maternal education (OR = 0.52; 95% CI 0.36-0.74) were associated with lower odds. Once RVV was initiated, recent birth years (2013-2016; OR = 1.57 [95% CI 1.32-1.88]) and higher maternal education (OR = 1.31; 95% CI 1.07-1.60) were associated with higher odds of RVV completion, whereas preterm birth (OR = 0.76; 95% CI 0.62-0.94), African American race (OR = 0.82; 95% CI 0.70-0.97) and public or no insurance (OR = 0.75; 95% CI 0.60-0.93) were associated with lower odds. Regional differences existed.

CONCLUSIONS

RVV coverage remains lower than that for the DTaP vaccine. Timely DTaP administration may help improve RVV coverage.

The first rotavirus vaccine and the politics of acceptable risk

Context

Vaccination in the United States is a frequent source of controversy, with critics alleging failures by public health officials to adequately identify, monitor, and respond to risks associated with vaccines. In response to these charges, the case of RotaShield, a vaccine withdrawn in 1999 following confirmation of a serious adverse event associated with its use, is regularly invoked as evidence of the effectiveness of current vaccine safety activities.

Methods

This article examines the history of RotaShield, with particular attention paid to decision making regarding its use in the United States and internationally. I reviewed and analyzed federal advisory committee meeting transcripts, international conference reports, government and scientific publications, media coverage, and other primary and secondary source materials. I also conducted six semistructured interviews with former senior officials and advisory committee members at the U.S. Centers for Disease Control and Prevention who participated in decisions regarding the vaccine.

Findings

Decision making regarding RotaShield, including the ultimate withdrawal of its recommendation for use, was shaped significantly by government health officials’ concern for preserving public confidence in overall U.S. vaccination efforts amid several unrelated vaccine risk controversies ongoing at that time. This attention to public perception and external pressures occurred in tandem with the evaluation of the quantitative evidence regarding the magnitude and severity of the risk associated with the vaccine. The decisions made in the United States resulted in foreseen but unintended consequences for international use of the vaccine, including in nations where the profile of risks and potential benefits was dramatically different.

Conclusions

As enthusiasm for evidence-based decision making grows throughout medicine and public health, greater explicit attention should be directed to the processes by which decision makers and their expert advisers evaluate such evidence and translate it into regulation and policy by means of qualitative judgments.

Prevention and treatment of viral diarrhea in pediatrics

Diarrhea is the second largest cause of mortality worldwide in children from the perinatal period to the age of 5 years. Rotavirus has been the most commonly identified viral cause of diarrhea in children. Norovirus is now recognized as the second most common viral pathogen. Adenovirus, astrovirus and sapovirus are the other major viral causes of pediatric gastroenteritis. Strategies for prevention include basic hygiene, optimization of nutrition and, ultimately, vaccination. Two new vaccines have recently been licensed for the prevention of rotavirus, the monovalent human rotavirus vaccine (Rotarix) and the pentavalent bovine-human reassortant vaccine (RotaTeq). These vaccines have already dramatically decreased the morbidity associated with rotavirus in countries where they are widely used. Efforts to develop a norovirus vaccine face substantial hurdles. Treatment of the viral pathogens is primarily limited to symptomatic measures.

The burden of rotavirus hospitalizations among Medicaid and non-Medicaid children younger than 5 years old

OBJECTIVES

We sought to compare the burden of hospitalizations associated with rotavirus gastroenteritis (RGE) in children younger than 5 years in US Medicaid and non-Medicaid populations in 2000 and 2003.

METHODS

We used the Kids' Inpatient Database (KID) to examine the burden of RGE-associated hospitalizations in terms of numbers and rates of hospitalizations, lengths of stay, and hospital charges. Two indirect methods were also used to estimate RGE-associated hospitalizations, because rotavirus testing is not routinely performed.

RESULTS

Approximately 40% of children younger than 5 years were enrolled in Medicaid in 2003, but this population accounted for nearly 50% of all RGE-associated hospitalizations and 60% of total charges. Children enrolled in Medicaid had significantly greater hospitalization rates, average lengths of stay, and average charges per stay than did those not enrolled.

CONCLUSIONS

Although RGE affects all socioeconomic groups, the Medicaid population accounted for a disproportionate number of the hospitalizations. With the inclusion of rotavirus vaccines in the pediatric immunization schedule, it is important that US children, especially those enrolled in Medicaid programs, are vaccinated to reduce the burden of RGE.

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.

Postlicensure monitoring of intussusception after RotaTeq vaccination in the United States, February 1, 2006, to September 25, 2007

BACKGROUND

In 1999, a previous rotavirus vaccine (RotaShield; Wyeth Laboratories, Marietta, PA) was withdrawn from the US market after postlicensure monitoring identified an association with intussusception. Although the new rotavirus vaccine (RotaTeq; Merck, West Point, PA) introduced in 2006 was not associated with intussusception in prelicensure trials, additional monitoring is important to ensure a complete safety profile.

METHODS

We assessed intussusception reports after RotaTeq vaccination by using data from the Vaccine Adverse Event Reporting System and the Vaccine Safety Datalink, a cohort of children enrolled in managed care. Observed versus expected rate ratios were determined by using vaccine dose distribution data and Vaccine Safety Datalink background intussusception rates.

RESULTS

Between February 1, 2006, and September 25, 2007, the Vaccine Adverse Event Reporting System received 160 intussusception reports after RotaTeq vaccination. With the assumptions that reporting completeness was 75% and that 75% of the distributed doses of RotaTeq were administered, the observed versus expected rate ratios were 0.53 and 0.91 for the 1-21 and 1-7 day interval after vaccination, respectively. In the Vaccine Safety Datalink, 3 intussusception cases occurred within 30 days after 111521 RotaTeq vaccinations, compared with 6 cases after 186722 non-RotaTeq vaccinations during the same period. If, like RotaShield, RotaTeq had a 37-fold increased risk of intussusception within 3 to 7 days after vaccination, then 8 intussusception cases would be expected within 3 to 7 days among the approximately 84000 infants vaccinated with the first dose of RotaTeq in the Vaccine Safety Datalink (N = 49902) and the prelicensure trial (N = 34035) combined, whereas no cases have been observed.

CONCLUSIONS

Available data do not indicate that RotaTeq is associated with intussusception. Although an intussusception risk similar in magnitude to that of RotaShield can be excluded, continued monitoring is necessary for complete assessment of the safety profile of RotaTeq.

Rotavirus diarrhoea and future prospects for prevention

Rotavirus is a highly contagious cause of vomiting and diarrhoea in young children (Glass et al, 2006). It is transmitted via the faecal-oral route and almost every child will experience an episode of rotavirus infection before the age of five years. Although this infection leads to millions of deaths per year in developing countries, good access to dehydration therapies in the UK means that we experience few rotavirus deaths. Nevertheless, rotavirus infection can cause misery for the child and presents indirect costs for parents. It also poses a substantial burden on primary care and paediatric wards, particularly during the busy winter period, with nosocomial infection adding, on average, a further four days to a child's stay in hospital. With no antiviral treatment available, management of the poorly child must focus on prevention of dehydration. Recently, two new generation rotavirus vaccines have been licensed with each undergoing extensive and large clinical trials. These vaccines offer new hope for the prevention of this condition.

Cost-effectiveness and potential impact of rotavirus vaccination in the United States

OBJECTIVE

In February 2006, a safe, efficacious, orally administered pentavalent human-bovine reassortant rotavirus vaccine was licensed and recommended for routine immunization of all children in the United States. We assessed the health and economic impacts of a national rotavirus immunization program in the United States.

METHODS

Monte Carlo cost-effectiveness analyses, from health care and societal perspectives, of vaccination of a hypothetical US birth cohort of 4,010,000 children monitored from birth to 59 months of age were performed. We compared the disease and economic burden of rotavirus infection in an unvaccinated cohort of children with one vaccinated at 2, 4, and 6 months with pentavalent human-bovine reassortant rotavirus vaccine.

RESULTS

A routine rotavirus immunization program would prevent 13 deaths, 44,000 hospitalizations, 137,000 emergency department visits, 256,000 office visits, and 1,100,000 episodes requiring only home care for children <5 years of age in the United States. Assuming costs of administration of $10, the break-even price per dose of vaccine was $42 from the societal perspective and $12 from the health care perspective. From the societal perspective, at the manufacturer's price of $62.50 per dose, vaccination would cost $138 per case averted, $3024 per serious case averted, and $197,190 per life-year saved, at a total cost of $515 million to the health care system and $216 million to society. Key variables influencing the results were parental workdays lost, costs of hospitalization, emergency department visits, and child care.

CONCLUSIONS

Despite a higher burden of serious rotavirus disease than estimated previously, routine rotavirus vaccination would unlikely be cost-saving in the United States at present. Nonetheless, rotavirus vaccination may still be considered a cost-effective intervention.

Rhesus rotavirus vaccine effectiveness and factors associated with receipt of vaccine

BACKGROUND

The rhesus rotavirus tetravalent vaccine (RotaShield) had an efficacy of 75%-100% in preventing severe rotavirus disease in prelicensure clinical trials. Before RotaShield's withdrawal because of reports of intussusception, there was an opportunity to evaluate the postlicensure effectiveness of the vaccine. The objective of this study was to determine the effectiveness of the RotaShield vaccine against rotavirus gastroenteritis requiring hospitalization and to evaluate factors associated with vaccine receipt.

METHODS

Rotavirus cases were identified through active hospital-based rotavirus surveillance at 3 children's hospitals in Cincinnati, New Orleans and Providence. Cases were selected if they had been eligible for vaccine during the 10-month period when vaccine was available. Controls were matched to cases by date and county or state of birth. Immunization records were obtained from cases and controls to document receipt of RotaShield. Vaccine effectiveness (VE) was calculated for 1, 2, and 3 doses of vaccine with 95% confidence intervals (CI).

RESULTS

For the 10-month period, 136 cases and 440 controls were enrolled. For 3 versus 0 doses of RotaShield, the VE was 100% (CI: 75%, 100%); for 2 versus 0 doses, the VE was 100% (CI: 62%, 100%), and for 1 versus 0 doses the VE was 89% (CI: 49%, 97%). RotaShield receipt was associated with white race, having more than 1 adult in the household, having insurance and having an older, more educated mother.

CONCLUSIONS

This postlicensure study of RotaShield effectiveness found the vaccine to be highly effective in preventing rotavirus disease requiring hospitalization.

Molecular epidemiology of adenovirus isolates from patients diagnosed with intussusception in Melbourne, Australia

Twenty-one intussusception (IS)-associated and 59 temporally linked adenoviral isolates from clinical infections were compared. Species C (15/21 IS- and 32/59 non-IS-associated isolates) dominated. Of these, serotype 2 (AdV-2) (7/15 IS-associated isolates) and serotype 1 (AdV-1) (16/32 non-IS-associated isolates) were the most commonly identified serotypes. DNA restriction analysis of AdV-2 isolates identified six genomic types; of these, type D2 (3/7 IS- and 8/11 non-IS-associated isolates) was the dominant type after BamHI and SmaI digestion. IS-associated isolates are similar to circulating non-IS-associated strains.

Rotavirus vaccines: current prospects and future challenges

Rotavirus is the most common cause of severe diarrhoea in children worldwide and diarrhoeal deaths in children in developing countries. Accelerated development and introduction of rotavirus vaccines into global immunisation programmes has been a high priority for many international agencies, including WHO and the Global Alliance for Vaccines and Immunizations. Vaccines have been developed that could prevent the enormous morbidity and mortality from rotavirus and their effect should be measurable within 2-3 years. Two live oral rotavirus vaccines have been licensed in many countries; one is derived from an attenuated human strain of rotavirus and the other combines five bovine-human reassortant strains. Each vaccine has proven highly effective in preventing severe rotavirus diarrhoea in children and safe from the possible complication of intussusception. In developed countries, these vaccines could substantially reduce the number and associated costs of child hospitalisations and clinical visits for acute diarrhoea. In developing countries, they could reduce deaths from diarrhoea and improve child survival through programmes for childhood immunisations and diarrhoeal disease control. Although many scientific, programmatic, and financial challenges face the global use of rotavirus vaccines, these vaccines-and new candidates in the pipeline-hold promise to make an immediate and measurable effect to improve child health and survival from this common burden affecting all children.

El papel de la vacuna frente a rotavirus en los calendarios de vacunación infantil

Rotavirus is the leading cause of diarrhea in infants. In developed countries, this infection leads to considerable morbidity with a high number of hospitalizations and medical interventions in the winter season, giving rise to substantial medical and social costs. In developing countries, rotavirus is a major cause of mortality in infants due to dehydration, with an estimated 600.000 deaths or more per year worldwide. A vaccine that is easy administrated, safe and with high efficacy would be the ideal means to reduce the burden of this disease and its high economic and social cost and to decrease the number of deaths in low-income countries. Recently, the results of two well-designed clinical trials with a large number of subjects have been reported. Both studies, which used different vaccines, reported high efficacy in the prevention of severe gastroenteritis and hospitalizations caused by rotavirus. When these vaccines become available in Europe, a reduction in hospitalizations, medical consultations, and days of work lost can be expected.

Temporal and geographic trends of rotavirus activity in the United States, 1997-2004

Rotavirus (RV) has a characteristic seasonal pattern in the 48 contiguous states of the continental United States, and climatologic factors have been implicated though not confirmed. Since 1997, three significant events occurred, including strong El Niño and La Niña climatologic phenomena, and the brief introduction of a rotavirus (RV) vaccine. We examined trends in RV activity in the continental United States between 1997 and 2004, using data from a network of over 70 laboratories that voluntarily report weekly RV detection rates within the National Respiratory and Enteric Virus Surveillance System (NREVSS). Analysis of NREVSS data indicates characteristic winter activity that begins in the Southwest in December or January, moves across the country, and ends in the Northeast in April or May. This pattern was not affected by the brief use of RV vaccine nor by periods of climate change associated with the El Niño and La Niña phenomena. The temporal and geographic pattern of RV spread in the United States has persisted since its initial description and defies easy explanation. An impact of the RV vaccine was not observed, either because of the limited uptake of the vaccine or the inherent variability of the system. NRVESS permits a gross assessment of RV geographic and temporal trends in the United States, but underscores the need for additional assessment mechanisms.

Intussusception among young children in Europe

Intussusception, a potentially lethal condition with poorly understood etiology, is the most common cause of acute intestinal obstruction in children younger than 5 years old. In some cases, the condition has been associated with administration of the first licensed rotavirus vaccine, the reassortant rhesus-human tetravalent rotavirus vaccine (RRV-TV; RotaShield). No such association has to date been reported from large phase III safety trials with new rotavirus vaccines. As 2 new, live-attenuated oral rotavirus vaccines are currently under review for approval by the European Union regulatory authorities, a review of the clinical, etiologic and epidemiologic aspects of intussusception in Europe is urgently needed. We conducted a review of Medline literature, published from 1995 onwards on intussusception in the World Health Organization's European Region. The results are compared with data from previous reviews and other regions. The classic triad of intussusception symptoms (abdominal pain, abdominal mass, bloody stools) was present in 29-33% of patients according to the medical literature reviewed. Conservative treatment (barium, air or saline enema) was the rule (81% of cases), and few complications were observed during treatment. Treatment outcome was generally favorable, with recurrence occurring in approximately 1 in 10 patients, and only 1 death reported. Structural lead points were seen in 3% of patients; no other reliable data on the etiology of intussusception were found. The incidence of acute intussusception in young children in Europe, according to 6 heterogeneous hospital-based studies, ranged from 0.66 to 2.24 per 1000 children in inpatient departments and from 0.75 to 1.00 per 1000 children in emergency departments. Peak incidences were found in children 3-9 months of age. There are still gaps in our knowledge of intussusception with respect to its etiology and especially by which mechanisms RRV-TV might have caused it to occur. Data from regions outside Europe showed that rotavirus infection and disease are not associated with intussusception. As new rotavirus vaccines become available for use in Europe, postlicensure surveillance for intussusception is indicated and may be instrumental in further understanding the epidemiology of this condition and in further assessing the safety of future vaccines.

More on RotaShield and intussusception: the role of age at the time of vaccination

BACKGROUND

RotaShield, a vaccine intended to prevent severe rotavirus diarrhea, was withdrawn in July 1999, 9 months after it became available in the United States, because of a temporal association with intussusception events that occurred in vaccinated infants. We explore here the effect of age on the risk of intussusception.

METHODS

We reanalyzed a case-control database of the Centers for Disease Control and Prevention by use of a 21-day window, to define vaccine-associated events. We obtained data on vaccine use from the National Immunization Survey and estimated the age-stratified background incidence of intussusception by use of Healthcare Cost and Utilization Project data. We combined these data to estimate how absolute risk varies with age and to model the projected population-attributable risk associated with 3 different vaccination schedules.

RESULTS

We found that the incidence of intussusception associated with the first dose of vaccine increased with age. Infants > or = 90 days old accounted for 80% of cases of intussusception associated with a first dose but had received only 38% of first doses. Modeling of the recommended schedule of vaccination at ages 2, 4, and 6 months projected 1 intussusception event/11,000-16,000 vaccine recipients; modeling of a 2-dose schedule beginning in the neonatal period projected 1 intussusception event/38,000-59,000 vaccine recipients.

CONCLUSIONS

The practice of initiating immunization after age 90 days, which we call "catch-up" vaccination, contributed disproportionately to the occurrence of intussusception associated with the use of RotaShield. A fully implemented 2-dose vaccination schedule begun during the neonatal period would lead to, at most, a 7% increase in the incidence of intussusception above the annual background incidence.

A Hexavalent Human Rotavirus–Bovine Rotavirus (UK) Reassortant Vaccine Designed for Use in Developing Countries and Delivered in a Schedule with the Potential to Eliminate the Risk of Intussusception

There is an urgent need for a rotavirus vaccine, because up to 592,000 infants and young children <5 years old die each year from rotavirus diarrhea, predominantly in the developing countries. We have developed a tetravalent human-bovine rotavirus (UK) reassortant vaccine with VP7 (G) specificity for serotypes 1, 2, 3, and 4, which has been shown to be safe, immunogenic, and effective in preventing severe rotavirus diarrhea. However, because of the emergence of VP7 (G) serotype 9 as an epidemiologically important serotype and the importance of VP7 (G) serotype 8 in focal areas, we are planning to add human-bovine (UK) reassortants with G8 and G9 specificity to the tetravalent vaccine, thereby formulating a "designed" hexavalent vaccine for universal use. In addition, we propose that the vaccine be administered orally in a 2-dose schedule, with the first dose given at 0-4 weeks of age and the second dose given at 4-8 weeks of age, when infants are relatively refractory to developing intussusception, thereby avoiding the age period when naturally occurring intussusception is most prevalent (i.e., ages 3-4 months through age 9 months). In this way, there may be the potential to eliminate or at least significantly decrease the risk of intussusception associated with rotavirus vaccination.

Intussusception and rotavirus vaccines

The association between the first oral rotavirus vaccine to be licensed in the U.S. (Rotashield) and intussusception has presented a major challenge to the effort to reduce the global burden related to rotavirus infection. Although the risk of developing intussusception following immunization with Rotashield is low, debate continues about the estimation of intussusception risk and the events surrounding the withdrawal of the vaccine. The experience with Rotashield has highlighted the wisdom of parallel clinical trials in developing and developed countries and the value of post-licensure surveillance for the detection of uncommon adverse events. This review retraces the steps leading up to the withdrawal of the Rotashield vaccine and reflects on how this experience has influenced the development of other rotavirus vaccines.

An analysis of rotavirus vaccine reports to the vaccine adverse event reporting system: more than intussusception alone?

BACKGROUND

The rhesus-human rotavirus reassortant-tetravalent vaccine (RRV-TV) was licensed on August, 31, 1998, and subsequently recommended for routine infant immunizations in the United States. After approximately 1 million doses had been administered, an increase in acute risk of intussusception in vaccinees led to the suspension of the use of RRV-TV and its withdrawal from the market. These postmarketing safety studies focused on a single adverse event (intussusception) and, to minimize the risk of a false-positive finding, accepted only cases that met a strict case definition. Safer rotavirus vaccines are needed to prevent the substantial global morbidity and mortality caused by rotavirus infections; their development and future use may benefit from a better understanding of the postmarketing safety profile of RRV-TV beyond intussusception.

OBJECTIVE

To characterize more completely the postmarketing surveillance safety profile of RRV-TV more completely by review and analysis of Vaccine Adverse Event Reporting System (VAERS) case reports to better understand 1) whether severe adverse events other than intussusception may have occurred after RRV-TV and 2) the likely scope of gastrointestinal illnesses, of which the previously identified, highly specific intussusception cases may account for just a fraction.

SETTING AND PARTICIPANTS

Infants vaccinated with RRV-TV and other vaccines in the United States and for whom a report was submitted to VAERS during September 1, 1998, to December 31, 1999.

METHODOLOGY

To detect adverse events of interest other than intussusception, we used proportional morbidity analysis to compare the adverse event profile of VAERS reports among infants who received routine vaccines including RRV-TV (after excluding confirmed and suspected intussusception reports) with infants who received identical vaccine combinations but without RRV-TV. Next, to better capture all described diagnoses, signs, and symptoms associated with the suspected adverse events, a set of new codes was developed and assigned to each VAERS report. All 448 nonfatal RRV-TV-associated reports (including intussusception) were recoded manually from the clinical description on the VAERS report and categorized into clinical groups to better describe a spectrum of reported illnesses after the vaccine. Each report was assigned to one of the following hierarchical and mutually exclusive clinical groups: 1) diagnosed intussusception; 2) suspected intussusception; 3) illness consistent with either gastroenteritis or intussusception; 4) gastroenteritis; 5) other gastrointestinal diagnoses (ie, not consistent with intussusception or rotavirus-like gastroenteritis); and 6) nongastrointestinal diagnoses.

RESULTS

Even after excluding intussusception cases, a higher proportion of RRV-TV reports than non-RRV-TV reports included fever and various gastrointestinal symptoms, most notably bloody stool but also vomiting, diarrhea, abdominal pain, gastroenteritis, abnormal stool, and dehydration. Distribution of RRV-TV reports by clinical groups was as follows: diagnosed intussusception (109 [24%], suspected intussusception (36 [8%]), and illness consistent with gastroenteritis or intussusception (33 [7%]), gastroenteritis (101 [22%]), other gastrointestinal diagnoses (10 [2%]), and nongastrointestinal outcomes (159 [35%]). The median time interval between vaccination and illness onset decreased incrementally among the first 4 clinical groups: from 7 days for diagnosed intussusceptions to 3 days for gastroenteritis.

CONCLUSIONS

Intussusception and gastroenteritis were the most commonly reported outcomes; however, a substantial number of reports indicate signs and symptoms consistent with either illness, possibly suggestive of a spectrum of gastrointestinal illness(es) related to RRV-TV. Although VAERS data have recognized limitations such as underreporting (that may differ by vaccine) and are nearly always insufficient to prove causality between a vaccine and an adverse event, this safety profile of RRV-TV may aid better understanding of the pathophysiology of intussusception as well as development of future safer rotavirus vaccines.