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(1/345) Rotavirus vaccine for the prevention of rotavirus gastroenteritis among children. Recommendations of the Advisory Committee on Immunization Practices (ACIP).

These recommendations represent the first statement by the Advisory Committee on Immunization Practices (ACIP) on the use of an oral, live rotavirus vaccine licensed by the Food and Drug Administration on August 31, 1998, for use among infants. This report reviews the epidemiology of rotavirus, describes the licensed rotavirus vaccine, and makes recommendations regarding its use for the routine immunization of infants in the United States. These recommendations are based on estimates of the disease burden of rotavirus gastroenteritis among children in the United States and on the results of clinical trials of the vaccine. Rotavirus affects virtually all children during the first 5 years of life in both developed and developing countries, and rotavirus infection is the most common cause of severe gastroenteritis in the United States and worldwide. In the United States, rotavirus is a common cause of hospitalizations, emergency room visits, and outpatient clinic visits, and it is responsible for considerable health-care costs. Because of this large burden of disease, several rotavirus vaccines have been developed. One of these vaccines - an oral, live, tetravalent, rhesus-based rotavirus vaccine (RRV-TV) -- was found to be safe and efficacious in clinical trials among children in North America, South America, and Europe and on the basis of these studies is now licensed for use among infants in the United States. The vaccine is an oral, live preparation that should be administered to infants between the ages of 6 weeks and 1 year. The recommended schedule is a three-dose series, with doses to be administered at ages 2, 4, and 6 months. The first dose may be administered from the ages of 6 weeks to 6 months; subsequent doses should be administered with a minimum interval of 3 weeks between any two doses. The first dose should not be administered to children aged > or =7 months because of an increased rate of febrile reactions after the first dose among older infants. Second and third doses should be administered before the first birthday. Implementation of these recommendations in the United States should prevent most physician visits for rotavirus gastroenteritis and at least two-thirds of hospitalizations and deaths related to rotavirus.  (+info)

(2/345) Intussusception among recipients of rotavirus vaccine--United States, 1998-1999.

On August 31, 1998, a tetravalent rhesus-based rotavirus vaccine (RotaShield, Wyeth Laboratories, Inc., Marietta, Pennsylvania) (RRV-TV) was licensed in the United States for vaccination of infants. The Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics, and the American Academy of Family Physicians have recommended routine use of RRV-TV for vaccination of healthy infants. During September 1, 1998-July 7, 1999, 15 cases of intussusception (a bowel obstruction in which one segment of bowel becomes enfolded within another segment) among infants who had received RRV-TV were reported to the Vaccine Adverse Event Reporting System (VAERS). This report summarizes the clinical and epidemiologic features of these cases and preliminary data from ongoing studies of intussusception and rotavirus vaccine.  (+info)

(3/345) Public health considerations for the introduction of new rotavirus vaccines for infants: a case study of tetravalent rhesus rotavirus-based reassortant vaccine.

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(4/345) Withdrawal of rotavirus vaccine recommendation.

In July 1999, CDC recommended that health-care providers and parents postpone use of the rhesus rotavirus vaccine-tetravalent (RRV-TV) (RotaShield, Wyeth Laboratories, Inc., Marietta, Pennsylvania), for infants, at least until November 1999. This action was based on reports to the Vaccine Adverse Event Reporting System of intussusception (a type of bowel obstruction that occurs when the bowel folds in on itself) among 15 infants who received rotavirus vaccine. Also at that time, the manufacturer, in consultation with the Food and Drug Administration, voluntarily ceased further distribution of the vaccine.  (+info)

(5/345) Intussusception among infants given an oral rotavirus vaccine.

BACKGROUND: Intussusception is a form of intestinal obstruction in which a segment of the bowel prolapses into a more distal segment. Our investigation began on May 27, 1999, after nine cases of infants who had intussusception after receiving the tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV) were reported to the Vaccine Adverse Event Reporting System. METHODS: In 19 states, we assessed the potential association between RRV-TV and intussusception among infants at least 1 but less than 12 months old. Infants hospitalized between November 1, 1998, and June 30, 1999, were identified by systematic reviews of medical and radiologic records. Each infant with intussusception was matched according to age with four healthy control infants who had been born at the same hospital as the infant with intussusception. Information on vaccinations was verified by the provider. RESULTS: Data were analyzed for 429 infants with intussusception and 1763 matched controls in a case-control analysis as well as for 432 infants with intussusception in a case-series analysis. Seventy-four of the 429 infants with intussusception (17.2 percent) and 226 of the 1763 controls (12.8 percent) had received RRV-TV (P=0.02). An increased risk of intussusception 3 to 14 days after the first dose of RRV-TV was found in the case-control analysis (adjusted odds ratio, 21.7; 95 percent confidence interval, 9.6 to 48.9). In the case-series analysis, the incidence-rate ratio was 29.4 (95 percent confidence interval, 16.1 to 53.6) for days 3 through 14 after a first dose. There was also an increase in the risk of intussusception after the second dose of the vaccine, but it was smaller than the increase in risk after the first dose. Assuming full implementation of a national program of vaccination with RRV-TV, we estimated that 1 case of intussusception attributable to the vaccine would occur for every 4670 to 9474 infants vaccinated. CONCLUSIONS: The strong association between vaccination with RRV-TV and intussusception among otherwise healthy infants supports the existence of a causal relation. Rotavirus vaccines with an improved safety profile are urgently needed.  (+info)

(6/345) Combination vaccines: defining and addressing current safety concerns.

Combination vaccines have been in use for >50 years. Historical problems with vaccines, including intussusception after rotavirus vaccine, carrier suppression with tetanus toxoid conjugate vaccines, and decreased immunogenicity of some Haemophilus influenzae type b conjugate vaccines when mixed with acellular pertussis-diphtheria-tetanus, have contributed to some misperceptions about current vaccines. There is no evidence that adding additional vaccines through combination products increases the burden on the immune system, which has the capability of responding to many millions of antigens. Combining antigens usually does not increase adverse effects-in fact, it can lead to an overall reduction in adverse events. Combination products simplify immunization and allow for the introduction of new vaccines without requiring the vaccinee to make additional visits to his or her health care provider. Licensed combination vaccines undergo extensive testing before approval by the United States Food and Drug Administration to assure that the new products are safe and effective.  (+info)

(7/345) Perspectives on the design and analysis of prelicensure trials: bridging the gap to postlicensure studies.

Recently, there has been growing concern regarding vaccine safety. Vaccines have led to the eradication of many serious diseases. Accordingly, there is less familiarity with the consequences of diseases and increasing concern with potential rare adverse events. The availability of clinical information systems within health maintenance organizations makes assessment of safety in larger cohorts, with power to assess rare adverse events, possible. However, no trial, no matter how large, can rule out all possible adverse events. There will always be the possibility that a rarer adverse event-just beyond the power of detection of a given trial-may occur. It is proposed that prelicensure trials in 10,000-40,000 children are now feasible. However, it will be necessary to develop an analytic continuum in which prelicensure studies are followed up with postmarketing assessments. Accordingly, the rapid identification of intussusception as a complication of rotavirus vaccination should not be seen as a failure of prelicensure studies but rather as a positive example of an effective integrated safety assessment program.  (+info)

(8/345) Enhancing vaccine safety surveillance: a capture-recapture analysis of intussusception after rotavirus vaccination.

The Vaccine Adverse Event Reporting System (VAERS) is the passive reporting system for postmarketing surveillance of vaccine safety in the United States. The proportion of cases of an adverse event after vaccination that are reported to VAERS (i.e., VAERS reporting completeness) is mostly unknown. Therefore, the risk of such an event cannot be derived from VAERS only. To study whether its reporting sensitivity and risks could be estimated, VAERS was linked to data from a case-control and a retrospective cohort study in a capture-recapture analysis of intussusception after rotavirus vaccination (RV). Cases of intussusception after RV were selected from the common time frame (December 1998 through June 1999) and the common geographic area (19 states) of the three sources. Matching occurred on birth date, gender, state, date of vaccination, and date of diagnosis. Thirty-five matches were identified among a total of 84 cases. The estimated VAERS reporting completeness was 47%. The relative risks of intussusception in the periods 3-7 and 8-14 days after RV (relative risk = 22.7 and 4.4, respectively) were comparable with those reported in the two studies. Linkage of VAERS to complimentary data sources may permit more timely postmarketing assessment of vaccine safety.  (+info)