ACIP Discusses Intussusception Risk From Rotavirus Vaccine, Limiting Tdap Administration

June 24, 2013 02:52 pm Matt Brown

An increased risk of intussusception from rotavirus vaccination and changes to delivery of the tetanus, diphtheria and acellular pertussis (Tdap) vaccine were among topics discussed by the CDC's Advisory Committee on Immunization Practices (ACIP) during its June 19-20 meeting(www.cdc.gov) in Atlanta.

According to Jamie Loehr, M.D., of Ithaca, N.Y., the AAFP's liaison to the ACIP, the committee reviewed data that indicate an increased risk of intussusception exists after administration of GlaxoSmithKline's Rotarix vaccine and, to a lesser degree, Merck and Co.'s Rotateq vaccine.

"The estimated range is 0.7 to 5.4 extra cases per 100,000 children who receive the rotavirus series," Loehr told AAFP News Now. "However, the vaccines have markedly decreased the number of hospitalizations and deaths from rotavirus.

"The estimates suggest that the vaccine prevents around 100 deaths, 1,000 hospitalizations and 10,000 ER visits for every one excess death, hospitalization or ER visit it might cause" based on the heightened intussusception risk, said Loehr. "Given this risk-benefit ratio, the CDC still strongly recommends using the vaccine in the U.S."

Story Highlights
  • The CDC's Advisory Committee on Immunization Practices (ACIP) discussed an increased risk of intussusception seen with rotavirus vaccination and changes to delivery of the tetanus, diphtheria and acellular pertussis (Tdap) vaccine during its recent meeting in Atlanta.
  • A slightly increased risk of intussusception has been seen with administration of both rotavirus vaccines currently marketed in the United States, but the CDC is not changing its immunization recommendations at this time.
  • The ACIP's pertussis work group now is recommending against a second dose of Tdap for adolescents and adults, instead calling for using the diphtheria and tetanus toxoids vaccine as a booster dose.

ACIP member and family physician Doug Campos-Outcalt, M.D., M.P.A., of Phoenix, said physicians simply need to be alert for signs of intussusception.

"The data that have been presented indicate that there is a low, but real, increased risk of intussusception from rotavirus vaccines within the first six days after receiving it," Campos-Outcalt said. "That risk does not appear to be particularly high, and so that is why researchers are going to spend a lot of time and effort in the next few months trying to get a more exact estimation of that (risk).

"Of course, intussusception occurs among all infants, and the vast majority of it is not caused by vaccines. This is just about heightened awareness for abdominal complaints in the first week out from the vaccine, but the risk is not high enough to make any change in the vaccine recommendations."

Pertussis Vaccine

According to the CDC, nearly 42,000 cases of pertussis were reported in the United States in 2012, the most in any year since 1955.

"We are seeing a resurgence of disease in older school-age children despite high levels of coverage," he said. "It appears that acellular vaccine protection wanes more quickly than whole-cell vaccine protection. A recent study shows that vaccine efficacy in adolescents in the first year after Tdap (is given) is 75 percent, but wanes quickly and drops to 39 percent at four years after Tdap."

Loehr said that the ACIP's pertussis work group is now recommending against a second dose of Tdap for adolescents and adults, instead calling for using the tetanus and diphtheria toxoids (Td) vaccine as a booster because the cost-benefit ratio seen with use of a second Tdap dose is poor.

"If a tetanus booster is needed and someone has already had Tdap in the past, the recommended booster is Td," Loehr said. "The only exception is that pregnant women are still recommended to have a Tdap vaccine with each pregnancy. That is not a formal recommendation (no vote was cast during the June ACIP meeting), but (the work group members) were giving us their analysis and letting us know they are not planning on recommending the use of Tdap."

Human Papillomavirus Vaccine

Loehr also said the pregnancy registry for Merck's human papillomavirus (HPV) vaccine Gardasil, which has been following a group of women for six years, did not show any increased risk of spontaneous abortions, fetal deaths or congenital anomalies.

"They are now closing the registry," he said. "They will still follow people, but they will not be as actively aggressive in managing it."

Committee members also discussed a number of other vaccine-related issues of interest to family physicians, including the following:

  • syncope is a frequently reported adverse reaction in adolescents, so a 15-minute observation period is recommended after vaccination;
  • the HPV work group provided data showing a decrease in HPV warts, as well as abnormal Pap smears, for patients who received the HPV vaccine; and
  • after the FDA expanded the indication for use of the inactivated Japanese encephalitis (JE) vaccine to include children ages 2 months to 16 years last month, the ACIP voted to recommend the vaccine for people as young as 2 months of age in certain circumstances.

"While this is not something many family physicians may deal with, the ACIP voted to recommend the JE vaccine for travelers (including children older than age 2 months) who plan to spend a month or longer in endemic areas during JE virus transmission season," Loehr said. "They also considered recommending the vaccine for travelers who are traveling for a shorter amount of time but have increased risk because of rural or agricultural travel."


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