Information on Immunization with Live Virus in Pediatric OMS
The Measles Outbreak
With the recent measles outbreak, multiple parents have asked whether their child with OMS should be immunized against measles. OMS is a special situation because for those children taking immunosuppressant drugs, an immunization presents a risk of relapse. In the past, we have advised against grouped vaccinations, and in particular we advised against live virus vaccines. However, measles has re-emerged in the U.S. after it was introduced from endemic areas, and because of lowered rates of vaccination here and in developing countries.
To consider the potential risks and potential benefits of measles immunization in children with OMS, the National Pediatric Myoclonus Center contacted the Centers for Disease Control (CDC) on 2/3/15. In a telephone conversation between Dr. Michael R. Pranzatelli and Dr. Ramond A. Strikas (Immunization Services Division, National Center for Immunization and Respiratory Diseases), the following issues were discussed.
What Is Measles?
Measles is caused by the measles virus. The symptoms include high fever, rash, cough, runny nose, and small spots in the mouth. The red blotchy rash begins on the face and head, spreading downward to include the truck and limbs. Measles is spread when an infected person coughs. The virus is carried by fine droplets that can remain suspended in the air for several hours even after the infected person left the area. Children with measles are contagious for up to 4-5 days before the rash appears. The incubation period between initial exposure to appearance of symptoms ranges up to 21 days. Most children in the U.S. recover, but rarely there can be severe complications. Encephalitis can occur in 1 of 1000 cases; death can occur in 2 of 1000 cases.
What Is the MMR Vaccine?
While it may be ideal in a child with OMS to vaccinate against measles alone, the single antigen vaccine (“measles monovalent vaccine”) is no longer manufactured. Measles immunization can only be conferred by the MMR II vaccine, which contains attenuated live viruses in a single injection, the measles, mumps, and rubella viruses. Attenuated means that the viruses have been treated to be weaker. The MMR II vaccine is usually first given to children > 12 months old, followed by a “booster” shot. About 95-98 % of those vaccinated respond to a single MMR dose. After the booster, 99% develop immunity to measles. Fever develops in 5-15% of persons immunized with MMR. In young children, there is a risk of seizures triggered by the fever in about 19 of 1000 that are immunized.
Can Measuring Antibody Titers Be Helpful?
An antibody “titer” is a laboratory test that measures the blood level of antibodies against a virus. If the titers are too low, the child is not immune to the virus. Antibody titer testing can help by checking for immunity.
When Are Live Virus Vaccines Prohibited?
High-dose steroids or ACTH suppress the immune response to infections, so patients taking these medications should not receive virus vaccines. Live virus vaccines are generally contraindicated when there is B cell suppression following rituximab or other anti-B-cell treatment.
Intravenous immunoglobulins (IVIg) generally IVIg prevent the body’s ability to make its own antibodies after an immunization. If one attempts to immunize a child against measles, the immunization is unlikely to be successful. The measles vaccine may not work for up to a year after IVIg has been discontinued, especially with chronic IVIg use.
What if an Immunosuppressed Child Is Exposed to Measles?
IVIg administered within 6 days is protective. IVIg gives temporary protection from measles because it contains IgG antibodies against measles from donors. It has a half-life in the bloodstream of 21 days after a dose.
What Is the Risk of OMS Relapse from Vaccination Years Later?
If your child went into a sustained remission from OMS and is doing well off medications for several years, the risk of an immunization-induced relapse appears to be lowered. If your child has chronic relapsing or progressive OMS (still has OMS symptoms and tends to relapse with infections), then there is a higher risk of immunization-induced relapse.
If you and your treating physician decide to give your child the MMR vaccine, please feel free to update us. You may also contact the CDC:
Centers for Disease Control and Prevention
Disclaimer: Immunization in OMS should be considered on a case-by-case basis. The capacity to tolerate killed virus vaccines may betoken a lower risk of relapse following live virus vaccines, but no one can absolutely predict the risk of relapse in a particular individual with a rare disorder. Therefore, all decisions about immunizations should be discussed with the physician who is familiar with your child’s health status and the risk of infections like measles in your community. Parents and physicians together should determine what potential risks they are prepared to take. The National Pediatric Myoclonus Center communicates this information as educational material to be shared with your physicians. We cannot assume any responsibility for how the information is used.
Selected ReadingMeasles cases exceed 100 in U. S. outbreak. British Medical Journal Feb 3;350:h622, 2015.
Center for Disease Control and Prevention. General Recommendations on Immunization. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 60(2). January 28, 2011.
WHO Position Paper on Vaccines against measles virus, September 2009.
Acknowledgments: Dr. Stephen Deputy and Dr. Warren Lo vetted the document.
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