Vaccines: VPD-VAC/Rotavirus/Rotashield and Intussusception ...

Rotavirus Vaccine (RotaShieldÂ®) and Intussusception
Historical information as RotaShield® was taken off U.S. market in 1999
The U.S. Advisory Committee on Immunization Practices (ACIP) voted on October 22, 1999 to no longer recommend use of the RotaShield® vaccine for infants because of an association between the vaccine and intussusception.
Questions about Rotashield® and Intussusception
Q: What was RotaShield®?
A: RotaShield® vaccine was the first vaccine to prevent rotavirus gastroenteritis approved for use in the United States in August 1998. For more information about rotavirus, see Question & Answers about Rotavirus.
Q: Did RotaShield® vaccine cause intussusception?
A: In the United States, some infants developed intussusception (defined below) soon after RotaShield® was licensed in August 1998. At first, it was not clear if the vaccine or some other factor was causing the bowel obstructions. CDC quickly recommended that use of the vaccine be suspended and immediately started two emergency investigations to find out if receiving RotaShield® vaccine was causing some of the cases of intussusception.
The results of the investigations showed that RotaShield® vaccine caused intussusception in some healthy infants younger than 12 months of age who normally would be at low risk for this condition. The risk of intussusception increased 20 to 30 times over the expected risk for children of this age group within 2 weeks following the first dose of RotaShield® vaccine. The risk increased 3 to 7 times over the expected risk for this age group within two weeks after the second dose of RotaShield® vaccine. There was no increase in the risk of intussusception following the third dose of RotaShield® vaccine, or when three weeks had passed following any dose of the vaccine.
Intussusception from all other causes is most common among infants in the first year of life; 1 child in 2,000 children to 1 child in 3,000 children is affected before one year of age. Based on the results of the investigations, CDC estimated that one or two additional cases of intussusception would be caused among each 10,000 infants vaccinated with RotaShield® vaccine.
Q: Was intussusception suspected before RotaShield® vaccine was licensed?
A: Among participants of 27 pre-licensing trials of several candidate rotavirus vaccines, five cases of intussusception occurred among 10,054 (0.05%) vaccine recipients; all were among infants who received a second or a third dose of vaccine. One case of intussusception occurred among 4,633 (0.02%) infants who received a placebo vaccine. The difference was not statistically significant between the groups. Careful evaluation was undertaken to evaluate if a relationship between receipt of the RotaShield® vaccine and intussusception might have occurred. None was found. As a precaution, intussusception was listed in the package insert of the vaccine as a possible side effects, and physicians were encouraged to report side effects of all kinds to the Vaccine Adverse Event Reporting System (VAERS) (See What is VAERS?).
Q: How many infants received the RotaShield® vaccine before it was withdrawn from use?
A: In studies before RotaShield® vaccine was licensed, about 7,000 infants received the vaccine. After RotaShield® vaccine was licensed, many more infants were vaccinated during the nine months that the vaccine was available. However, the exact number of infants who received RotaShield® is not known. In the two investigations conducted by CDC, overall, fewer than 13% of infants who were younger than one year of age had been vaccinated with one or more dose of the three-dose series.
Q: Is RotaShield® vaccine still available in the United States?
A: RotaShield® vaccine is no longer available for use in the United States.
Q: What action did CDC take when cases of intussusception were reported to VAERS?
A: CDC, in collaboration with the Food and Drug Administration (FDA), and state and local health departments throughout the United States, conducted two large investigations. One was a multi-state investigation which evaluated whether or not rotavirus vaccine was associated with intussusception. Based on the results of the investigation, CDC estimated that RotaShield® vaccine increased the risk for intussusception by one or two cases of intussusception among each 10,000 infants vaccinated. The other was a similar investigation in children vaccinated at large managed care organizations. When the results of these investigations became available, the Advisory Committee on Immunization Practices (ACIP) withdrew its recommendation to vaccinate infants with RotaShield® vaccine, and the manufacturer voluntarily withdrew RotaShield® from the market in October 1999.
Q: Why did CDC take this action?
A: The decision to stop recommending use RotaShield® vaccine in the United States was made by the Advisory Committee on Immunization Practices (ACIP), American Academy of Pediatrics (AAP) and the American Academy of Family Physicians (AAFP) because intussusception is a serious condition and because of the perception that most of the severe complications of rotavirus gastroenteritis in the United States can be prevented by oral rehydration.
A primary goal of CDC is to protect the health and safety of the general public in the United States. One of the most effective ways to prevent disease is through vaccination. However, when a vaccine is discovered to have a serious side effect, a recommendation to continue using the vaccine will be reconsidered and the vaccine may be withdrawn, in spite of the beneficial effect of the vaccine to prevent disease.
The vaccine safety monitoring systems worked to detect an uncommon side effect. Rotavirus vaccination was promptly suspended and new cases of intussusception were prevented.
Q: How did parents report intussusception to CDC during that time?
A: If a child developed intussusception or any serious reaction after a vaccine, whether or not it is thought to be related to the vaccine, the child should have received prompt medical attention and the reaction should have reported to VAERS (See What is VAERS?). VAERS reporting forms and information can be requested 24 hours a day by calling (800) 822-7967 or online.
Q: What is VAERS?
A: VAERS is the Vaccine Adverse Event Reporting System. It is a passive surveillance system jointly operated by the FDA and CDC. VAERS receives reports from manufacturers, physicians and other healthcare providers, patients and their parents or guardians, and anyone else who wants to report a suspected adverse reaction following vaccination. Many adverse events that follow vaccination are not caused by the vaccine, so VAERS data should be interpreted with caution. Nonetheless, VAERS reports can provide the first clue that a problem exists. Additional studies can then be conducted to answer the questions raised by VAERS reports, as was done in response to the reported cases of intussusception following administration of RotaShield® vaccine.
General Questions about Intussusception
Q: What is intussusception?
A: Intussusception is a rare type of bowel obstruction that occurs when the bowel folds in on itself. Intussusception is most common among young children. The most common place in the intestine for intussusception to occur is where the small bowel joins the large bowel. However, intussusception can occur in many parts of the intestine. With prompt treatment, almost all patients fully recover.
Q: What are the symptoms of intussusception?
A: Infants with intussusception become ill with vomiting, abdominal pain and often have blood in the stool. Some infants will have periods of crying in pain alternating with periods of exhausted sleep. Parents of infants with these symptoms should seek medical advice because their infant may require prompt medical evaluation.
Q: What causes intussusception?
A: In most cases, no cause is identified. Some cases have been associated with infection, such as adenovirus, or with a structural abnormality such as a polyp or tumor.
Q: How is intussusception treated?
A: An experienced radiologist often can “unfold” the intussusception using an “enema” of air or fluid under pressure to push the enfolded intestine back into its normal position. When this does not work, surgery is required to “unfold” the intestine. In a small percentage of children, it is necessary to remove the section of intestine that is causing the blockage.