Issue Number
125
November 5, 1999
CONTENTS OF THIS ISSUE
- CDC publishes article on the withdrawal of rotavirus
vaccine recommendation by ACIP
- CDC publishes article on recommendations on the use of
vaccines containing thimerosal as preservative
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(1)
November 5, 1999
CDC PUBLISHES ARTICLE ON THE WITHDRAWAL OF ROTAVIRUS VACCINE RECOMMENDATION BY ACIP
The Centers for Disease Control and Prevention (CDC) published an article titled "Withdrawal of Rotavirus
Vaccine Recommendation" in the November 5,1999, issue of the MMWR. The full text of the article reads as follows:
In July 1999, CDC recommended that health-care providers and parents postpone use of the rhesus rotavirus
vaccine-tetravalent (RRV-TV) (RotaShield, Wyeth Laboratories, Inc., Marietta, Pennsylvania), for infants, at
least until November 1999. This action was based on reports to the Vaccine Adverse Event Reporting System of intussusception
(a type of bowel obstruction that occurs when the bowel folds in on itself) among 15 infants
who received rotavirus vaccine. Also at that time, the manufacturer, in consultation
with the Food and Drug Administration, voluntarily ceased further distribution of the vaccine.
On October 22, 1999, the Advisory Committee on Immunization Practices (ACIP), after a review of scientific data from
several sources, concluded that intussusception occurs with significantly increased frequency in the first 1-2
weeks after vaccination with RRV-TV, particularly following the first dose. Therefore, ACIP no longer recommends vaccination
of infants in the United States with RRV-TV and withdraws its recommendation that RRV-TV be
administered at 2, 4, and 6 months of age. Children who received rotavirus vaccine
before July and remain well are not now at increased risk for intussusception.
Rotavirus remains the cause of a substantial health burden for children in the
United States. It accounts for 20-40 deaths annually, and greater than 50,000
hospitalizations from severe diarrhea and dehydration. Vaccination against
rotavirus would be the optimal means to prevent such illnesses. RRV-TV was recommended because it was shown
in prelicensure trials to be a safe and effective vaccine. In those trials, RRV-TV prevented rotavirus in at least
50% of cases of diarrhea and almost all of the hospitalizations. Postlicensure
evaluation, however, has identified intussusception as an uncommon, serious adverse
event associated with the vaccine.
The relation between intussusception and RRV-TV merits further research. The findings could impact directly on use
of this and other rotavirus vaccines. In addition, the worldwide burden of rotavirus disease remains substantial.
Thus, the ACIP's decision may not be applicable to other settings, where the
burden of disease is substantially higher and where the risks and benefits of
rotavirus vaccination could be different.
In the United States, rotavirus remains the primary cause of parents seeking
health care for children with severe dehydrating diarrhea, particularly during
the winter. Because of the withdrawal of this vaccine recommendation, the ACIP recommends that educational
efforts be directed at parents and health-care providers to help parents prevent dehydration and to recognize
and immediately seek medical care for severe diarrhea in children. These efforts should focus on the early
diagnosis and treatment of severe dehydration from diarrhea, particularly among infants and children aged
less than or equal to 5 years.
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To obtain the text version (HTML format) of this MMWR article online, go to:
http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/mm4843a5.htm
For additional information on rotavirus vaccine, visit CDC's "Rotavirus" Internet page located on the National
Immunization Program website at: http://www.cdc.gov/nip/news/rota-news.htm
(link discontinued).
You can also find information on rotavirus vaccine
on the Immunization Action Coalition's website at: http://www.immunize.org/genr.d/rotainfo.htm
To obtain more information from CDC about managing severe diarrhea in children, go to:
http://www.cdc.gov/od/oc/parents/
For information on how to obtain a free electronic subscription to the MMWR,
see the instructions that follow article two below.
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(2)
November 5, 1999
CDC PUBLISHES ARTICLE ON RECOMMENDATIONS ON THE USE OF VACCINES CONTAINING THIMEROSAL AS A PRESERVATIVE
The Centers for Disease Control and Prevention (CDC) published an article entitled "Recommendations Regarding
the Use of Vaccines That Contain Thimerosal as a Preservative" in the November 5, 1999, issue of the MMWR.
The full text of the article (with the exception of Table 1) reads as follows:
On October 20, 1999, the Advisory Committee on Immunization Practices (ACIP) reviewed information about thimerosal in
vaccines and received updates from CDC's National Immunization Program and several vaccine
manufacturers on the current and anticipated availability of vaccines that do
not contain thimerosal as a preservative. The review was prompted by a joint
statement about thimerosal issued July 8, 1999, by the American Academy of Pediatrics (AAP) and the Public Health
Service (PHS) and a comparable statement released by the American Academy of Family Physicians. These
statements followed a Congressionally mandated Food and Drug Administration (FDA) review of mercury in drugs and food, which included a
reassessment of the use of thimerosal in vaccines.
Thimerosal is a mercury-containing preservative that has
been used as an additive in biologics and vaccines since the 1930s because it prevents
bacterial and fungal contamination, particularly in multidose containers. Given
the widely acknowledged value of reducing exposure to mercury, vaccine manufacturers, FDA, and other PHS agencies are
collaborating to reduce the thimerosal content of vaccines or to replace them with formulations that do not
contain thimerosal as a preservative as soon as possible without causing unnecessary disruptions in the vaccination system.
FDA will expedite review of supplements to manufacturers' product license applications that present
formulations for eliminating or reducing the mercury content of vaccines.
Hepatitis B, DTaP, and Hib Vaccines
A single-antigen, preservative-free hepatitis B vaccine (Recombivax HB, Merck & Co., Inc., West Point, Pennsylvania)
was licensed on August 27, 1999, and a second hepatitis B vaccine (Engerix-B, SmithKline Beecham
Biologicals, Philadelphia, Pennsylvania) that is preservative-free is under consideration for licensure. One manufacturer
reported that the supply of its diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine that
does not contain thimerosal as a preservative would be sufficient to meet any
increased demand during the next year, and three other manufacturers are developing similar DTaP
vaccines that could be licensed in the future. Multiple single-antigen Haemophilus influenzae type b (Hib) vaccines
and the hepatitis B/Hib combination vaccine that do not contain thimerosal as a preservative
are licensed, and the supply of these products is adequate to meet national needs.
The risk, if any, to infants from exposure to thimerosal is believed to be slight.
The demonstrated risks for not vaccinating children far outweigh the theoretical risk
for exposure to thimerosal-containing vaccines during the first 6 months of life.
Given the availability of vaccines that do not contain thimerosal as a preservative, the progress in developing
such additional vaccines, and the absence of any recognized harm from exposure to thimerosal in vaccines,
hepatitis B, DTaP, and Hib vaccines that contain thimerosal as a preservative
can continue to be used in the routine infant schedule beginning at age 2 months along with monovalent or
combination vaccines that do not contain thimerosal as a preservative.
Reported failures to vaccinate newborns at high risk for perinatal hepatitis B
virus (HBV) transmission suggest that some institutions may have misinterpreted or improperly
implemented the recommendations contained in the joint statement by the AAP and PHS--and subsequent clarification--to
postpone hepatitis B vaccination only for newborns who are not at high risk.
Chronic HBV infection develops in approximately 90% of infants infected at birth; among
chronically infected infants, the risk for premature death from HBV-related liver cancer or cirrhosis is approximately
25%. All hospitals and pediatric care providers should ensure that newborn infants receive hepatitis
B vaccine as recommended. If the supply of single-antigen hepatitis B vaccines that do not contain thimerosal as a preservative
is limited, the priority for its use should be to vaccinate newborn infants.
[See Table 1, "Recommendations for hepatitis B vaccination of newborn infants with thimerosal-containing vaccines and
vaccines that do not contain thimerosal as a preservative," by clicking on the link that follows this article.]
Influenza Vaccine
All influenza vaccines contain thimerosal; however, ACIP recommends no changes in the influenza vaccination guidelines,
including those for children and pregnant women. Evidence suggests that children with certain medical
conditions (e.g., cardiopulmonary disease, including asthma) are at substantially increased risk for complications of influenza.
During the influenza season, rates of cardiopulmonary hospitalizations for otherwise
healthy women in their second or third trimester of pregnancy are similar to
that among persons aged greater than or equal to 65 years who do not have a chronic medical illness and for whom influenza
vaccination is also recommended. Pregnant women with chronic medical conditions are at higher
risk and have a hospitalization rate more than two times greater than among
pregnant women without other high-risk medical conditions. A substantial safety margin has been incorporated into the
health guidance values for organic mercury exposure developed by the Agency for Toxic Substances
and Disease Registry and other agencies. ACIP concluded that the benefits of influenza
vaccine outweigh the potential risks for thimerosal.
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To obtain the text version (HTML format) of this MMWR article online including
the table titled "Recommendations for hepatitis B vaccination of newborn infants with
thimerosal-containing vaccines and vaccines that do not contain thimerosal as a preservative," go to:
http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/mm4843a4.htm
For additional information on thimerosal in vaccines, visit CDC's "Thimerosal"
information page online on the National Immunization Program website at: www.cdc.gov/nip/news/thimerosal.htm
(link discontinued).
You can also find information on thimerosal and vaccines on the Immunization
Action Coalition's website at: http://www.immunize.org/genr.d/thimer.htm
HOW TO GET A FREE ELECTRONIC SUBSCRIPTION TO THE MMWR
To obtain a free electronic subscription to the MMWR (delivered weekly), visit
CDC's MMWR website: http://www2.cdc.gov/mmwr/
Once you are at this site go to the menu on the left side of the screen and select
"Free MMWR Subscription." After you have submitted the required information, weekly
issues of the MMWR and all new ACIP statements (published as MMWR's "Recommendations
and Reports") will automatically arrive in your e-mail box. |
