The Risk of Immune Thrombocytopenic Purpura After Vaccination in Children and Adolescents

Abstract

WHAT'S KNOWN ON THIS SUBJECT: Studies on vaccine safety are crucial to the ongoing success of our national immunization program. ITP has a known association with MMR in young children, occurring in 1 in 40 000 doses. The risk after other childhood vaccines is unknown. WHAT THIS STUDY ADDS:This study found no increased risk of ITP after vaccines other than MMR in young children, confirmed an association of ITP with MMR, and also found that ITP may occur after certain other vaccines in older children.abstract BACKGROUND: The risk of immune thrombocytopenic purpura (ITP) after childhood vaccines other than measles-mumps-rubella vaccine (MMR) is unknown. METHODS:Using data from 5 managed care organizations for 2000 to 2009, we identified a cohort of 1.8 million children ages 6 weeks to 17 years. Potential ITP cases were identified by using diagnostic codes and platelet counts. All cases were verified by chart review. Incidence rate ratios were calculated comparing the risk of ITP in risk (1 to 42 days after vaccination) and control periods.RESULTS: There were 197 chart-confirmed ITP cases out of 1.8 million children in the cohort. There was no elevated risk of ITP after any vaccine in early childhood other than MMR in the 12-to 19-month age group. There was a significantly elevated risk of ITP after hepatitis A vaccine at 7 to 17 years of age, and for varicella vaccine and tetanus-diphtheria-acellular pertussis vaccine at 11 to 17 years of age. For hepatitis A, varicella, and tetanus-diphtheria-acellular pertussis vaccines, elevated risks were based on one to two vaccine-exposed cases. Most cases were acute and mild with no long-term sequelae.CONCLUSIONS: ITP is unlikely after early childhood vaccines other than MMR. Because of the small number of exposed cases and potential confounding, the possible association of ITP with hepatitis A, varicella, and tetanus-diphtheria-acellular pertussis vaccines in older children requires further investigation. 2 Since then, the association of live attenuated measles-mumps-rubella (MMR) vaccine and ITP has been well established. [3][4][5][6][7][8][9][10][11] ITP is known to occur after many types of infections, including numerous vaccine-preventable diseases. [12][13][14][15][16][17][18] In approximately two-thirds of ITP cases, there is a history of a preceding infectious illness in the days to weeks before ITP onset. 19 A subset of these children will have an identifiable virus, such as Epstein-Barr virus, varicella zoster virus, influenza virus, or HIV. 16 Because vaccines are designed to induce an immune response that mimics natural infection to produce immunologic protection, it is theoretically possible that vaccines besides MMR could trigger ITP. In addition, there have been case reports of ITP after other childhood vaccines, including hepatitis B vaccine (HBV), diphtheria-tetanuspertussis vaccine (DTP), and hepatitis A vaccine (Hep A). [20][21][22][23][24][25] However, the risk of ITP after childhood vaccines other than MMR is currently unknown.Known rare severe complica...

Safety of Measles-Containing Vaccines in 1-Year-Old Children

“…The similarly elevated risk for ITP after either vaccine is consistent with previous studies which found increased ITP risk after MMR in children. [8][9][10] To our knowledge, the present study represents the first report that MMRV is associated with a similar increased risk of ITP during the same postvaccination risk intervals as MMR.…”

“…The measles-mumps-rubella (MMR) vaccine has been associated with several safety outcomes, including febrile seizures, [1][2][3][4] fever, [5][6][7] immune thrombocytopenia purpura (ITP), [8][9][10] anaphylaxis, [11][12][13] and possibly arthritis/arthralgia. 14 After licensure of the combination measles-mumpsrubella-varicella vaccine (MMRV), the Advisory Committee on Immunization Practices recommended in 2006 that it preferred use of the MMRV over separate MMR and varicella (V) vaccines for the 2 recommended doses at 12 to 15 months and 4 to 6 years of age.…”

Public health: An injection of trust

“…"We can update these databases weekly, and thus virtually conduct real-time monitoring when a new vaccine is introduced, " says Frank DeStefano, director of the CDC's Immunization Safety Office. Data from the VSD helped disprove the connection between MMR and autism, but have also identified real adverse events, such as when 197 children in a cohort of 1.8 million who had received the MMR vaccination developed immune thrombocytopaenic purpura 4 . "It's a relatively benign blood disorder where there's easy bruising and bleeding, but it can be scary, " says Jason Glanz, an epidemiologist affiliated with the VSD at the Kaiser Permanente Institute for Health Research in Denver, Colorado.…”

Idiopathic Thrombocytopenic Purpura Is More Severe in Children with a Recent History of Vaccination

“…The incidence of ITP is estimated at 50-100 new cases per million per year (6,7). ITP in children is usually self-limiting, with a typically acute onset and frequently occurring a few days or weeks after viral infection or vaccination (8)(9)(10)(11)(12). At least 70 percent of childhood cases will end up in remission within six months, even without treatment (7,(13)(14)(15)(16).…”

“…Acute ITP was considered to be associated with the use of a vaccine in case there was no recognized etiology and the interval between vaccination and onset of acute ITP symptoms was within 5 weeks (19). However, none of the routine childhood vaccines given in the first year of life was known to be significantly associated with an increased risk of ITP (20). Studies reporting a link between MMR vaccination and ITP have been criticized because concomitant viral infections have not usually been excluded.…”