Questions & Answers

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When did a rotavirus vaccine become available?
A vaccine to prevent rotavirus gastroenteritis was first licensed in August 1998 but was withdrawn in 1999 because of its association with an uncommon type of bowel obstruction called "intussusception."

In February 2006, the U.S. Food and Drug Administration (FDA) approved a new rotavirus vaccine, RotaTeq (by Merck). In April 2008, FDA approved a second rotavirus vaccine, Rotarix (by GlaxoSmithKline).

What kind of vaccine are they?
RotaTeq and Rotarix are both live attenuated vaccines.

How is this vaccine given?
Both RotaTeq and Rotarix are liquids given orally (swallowed).

Who should get this vaccine?
National experts on immunization (such as the Centers for Disease Control and Prevention and the American Academy of Pediatrics) recommend routine vaccination of all infants with rotavirus vaccine.

What is the recommended schedule for getting this vaccine?
Both vaccines are given in a series: RotaTeq vaccine is given in a 3-dose series with doses given at 2, 4, and 6 months; Rotarix vaccine is given in a 2-dose series with doses given at 2 and 4 months.

The first dose of either vaccine can be given as early as age 6 weeks or as late as age 14 weeks, 6 days. Vaccination should not be started for infants once they reach their 15 week birthday. There must be at least 4 weeks between doses and all doses must be given by age 8 months. Rotavirus vaccine may be given at the same time as other childhood vaccines.

Should an infant who has already been infected with rotavirus still be vaccinated?
Yes. Infants who have recovered from a rotavirus infection may not be immune to all of the virus types present in the vaccine. These infants should complete the series if they can do so by age 8 months.

How safe is this vaccine?
Clinical trials to determine the safety and effectiveness of the RotaTeq vaccine involved more than 70,000 infants age 6-12 weeks in 11 countries. There was not a clinically significant difference in the incidence of vomiting, diarrhea, fever, irritability, or poor feeding in children who got the vaccine versus those who didn't.

Because of the association of the earlier rotavirus vaccine with intestinal blockage, a study designed specifically to assess a risk of intussusception was conducted before licensure of RotaTeq. The vaccine was given to 35,000 children and another 35,000 were given a placebo (salt water). There was no difference in the incidence of intestinal blockage between the two groups.

As with all vaccines, the safety of this vaccine is being monitored after licensure by the U.S. Food and Drug Administration (FDA) and by CDC through the Vaccine Adverse Event Reporting System. In addition, Merck and Co., Inc., has committed to conducting another study of its RotaTeq vaccine in approximately 44,000 children, and CDC will also conduct a large study in its Vaccine Safety Datalink Program, which evaluates vaccine safety among approximately 80,000 U.S. infants every year. Also, for the first three years of licensure, the manufacturer will report cases of intussusception to FDA within 15 days of receiving them, and all other serious side effects on a monthly basis.

As a result of this aggressive monitoring, on February 13, 2007, the FDA released a report on the number of intussusception cases reported since RotaTeq licensure. The number reported fell within what was expected and gives assurance that the vaccine does not pose an elevated risk for intussusception. To read the report, go to www.fda.gov/cber/safety/phnrota021307.htm To read a CDC Q&A about the report, go to www.cdc.gov/vaccinesafety/vaers/rotateq.htm

The FDA’s approval of Rotarix in 2008 was based on clinical trials involving nearly 75,000 infants. These clinical trials were conducted in the Americas, Europe, Asia and Africa and reflect an ethnically diverse population.

In a controlled safety study conducted in Latin America and Finland, the risk of intussusception was evaluated in 63,225 infants. No increased risk of intussusception following administration of ROTARIX was observed within a 31-day period following any dose, and rates were comparable to the placebo group after a median of 100 days. In a subset of 20,169 infants (10,159 received Rotarix and 10,010 received placebo) followed up to one year after dose 1, there were 4 cases of intussusception with Rotarix compared with 14 cases of intussusception with placebo. All of the infants who developed intussusception recovered without sequelae. As with RotaTeq, the safety of Rotarix continues to be monitored.

How effective is the vaccine?
Rotavirus vaccine is very effective against rotavirus disease. Studies show the vaccine to be highly effective (90-98%) against severe rotavirus disease and very effective against moderate disease (74-79%). Chances that ill children will be hospitalized are also greatly decreased (96%) by the vaccine. Neither vaccine will prevent diarrhea or vomiting caused by other viruses.

What side effects have been reported with this vaccine?
Vaccinated children are slightly (1-3%) more likely to have mild, temporary diarrhea or vomiting within 7 days after getting a dose of vaccine than children who did not get the vaccine. Moderate or severe reactions have not been associated with the vaccine.

Who should NOT receive rotavirus vaccine?
Any child who has had a severe (life-threatening) allergic reaction to a previous dose of rotavirus vaccine should not get another dose. A child with a severe (life-threatening) allergy to any component of rotavirus vaccine should not get the vaccine. Because the oral applicator for Rotarix contains latex rubber, infants with a severe (anaphylactic) allergy to latex should not be given Rotarix; the RotaTeq dosing tube is latex-free.

Although this vaccine has not been associated with intussusception, as a precaution it is suggested that the risks for and the benefits of vaccination should be considered when vaccinating infants with a previous episode of intussusception.

Children who are moderately or severely ill at the time the vaccination is scheduled should probably wait until they recover, including children who are experiencing diarrhea or vomiting. Healthcare providers will decide on a case-by-case basis whether to vaccinate a child with an ongoing digestive problem, an immune system weakened because of HIV/AIDS or another disease that affects the immune system, or a child who is receiving treatment with drugs such as long-term steroids or treatment for cancer.

Can the vaccine cause rotavirus?
No. The vaccine contains attenuated viruses that are reassorted and do not exist in nature. The vaccine may cause mild symptoms similar to those experienced during rotavirus infection but cannot cause rotavirus disease.

Questions and answers about rotavirus disease

Technically reviewed by the Centers for Disease Control and Prevention, January 2009