Questions & Answers
Anthrax - The Anthrax Vaccine
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Vaccination and Reproductive Health

  1. Can the anthrax vaccine be taken by military members who are pregnant?
    It is DoD policy not to give anthrax vaccine to women who are pregnant or who think they may be pregnant. This is consistent with the general practice of withholding most medications from women who are pregnant. Most vaccinations are routinely deferred until after pregnancy, unless immunity is needed during pregnancy. Tetanus, meningococcal, hepatitis B, and influenza vaccines, for example, are specifically recommended for susceptible women during their pregnancy. As with other vaccines in the U.S., studies on possible reproductive side effects by intentionally giving anthrax vaccine to pregnant women have not been performed. However, there has been no confirmed evidence of infertility, miscarriages, or other reproductive problems with the use of inactivated vaccines. Because the anthrax vaccine is a sterile, cell-free (filtered) bacterial vaccine, it is non-infectious and is not expected to cause any harm to the fetus. If a pregnant woman is known to have been exposed to anthrax, she could be offered the vaccine as a potential life-saving measure. Women who believe that they may be pregnant should inform their health-care provider before vaccination. Once pregnancy is confirmed, anthrax vaccinations will be deferred until the woman is no longer pregnant. Once a woman is no longer pregnant, deferred anthrax vaccination will resume. A woman can safely become pregnant any time after vaccination that she wishes. Preliminary data from the Naval Health Research Center raised a tentative signal that there may be an association with an increased rate of birth defects. This signal is being investigated thoroughly, to determine which of several explanations for the signal is most likely.

  2. What happens to vaccinated women who later get pregnant?
    In the March 27, 2002, issue of the Journal of American Medical Associations, two Army physicians published findings that women get pregnant at the same rate, whether anthrax-vaccinated or unvaccinated. These physicians from Fort Stewart, Georgia, also showed that women deliver offspring at the same rate, whether anthrax-vaccinated or unvaccinated. The Fort Stewart study found no difference in birth defect rates, either, but the study may have been too small to detect small differences. Long-standing Department of Defense policy is to defer routine vaccinations in women until after pregnancy. This policy has always applied to anthrax vaccine. Women are asked if they are pregnant before vaccination. Women who are not sure are offered pregnancy tests.

  3. What about men who get vaccinated? Should they delay fathering a child?
    No. For all the same reasons mentioned above, there is no reason for a man to delay fathering a child after vaccination. A man can safely father a child any time after vaccination that he wishes. Data about anthrax vaccination was obtained from men at time of oocyte and sperm retrieval. Researchers assessed characteristics of male gametes, including 254 vaccinated men and 791 unvaccinated men. The two groups were comparable for semen concentration (million sperm per milliliter), sperm motility (movement), sperm morphology (shape), need for intracytoplasmic sperm injection, and rate of fertilization of mature oocytes, embryo transfer, and clinical pregnancy. A diagnosis of male-factor infertility was less common in anthrax-vaccinated men than in unvaccinated men. The researchers concluded that anthrax vaccination of men did not impair semen parameters, fertilization rate, embryo quality, or clinical pregnancy rates.

  4. What about a woman who is taking fertility-enhancing drugs in an effort to become pregnant?
    No drug interactions are known between fertility medications (such as clomiphene, Clomid) and any vaccination. Women on fertility-enhancing drugs receive all DoD vaccinations on schedule until they have a positive pregnancy test. At this point, further vaccinations are deferred as described above.

  5. For More Information:
    Advisory Committee on Immunization Practices. General recommendations on immunization. Morbidity & Mortality Weekly Report (MMWR) 2002; volume 51 (No. RR-2): pages 1-36;

    American College of Obstetricians & Gynecologists, Committee Opinion, Immunization During Pregnancy, 2003; 282:1-6.

    Brachman PS, Friedlander AM. Anthrax. In: Plotkin SA, Orenstein WA, ed. Vaccines, 3rd ed. Philadelphia: W. B. Saunders, 2003.

    Centers for Disease Control & Prevention. Status of U.S. Department of Defense preliminary evaluation of the association of anthrax vaccination and congenital anomalies. MMWR 2002; 51:127.

    Catherino WH, Levi A, Leondires M, Segars JH, Alvero R, McKeeby J. Fertility & Sterility (Abstracts) Vol. 78, No. 3, Suppl. 1, September 2002, pages S108-S109.

    Food & Drug Administration. Biological products; Bacterial vaccines and toxoids; Implementation of efficacy review. Federal Register 1985; 50:51002-117.

    Inglesby TV, O'Toole T, Henderson DA, Bartlett JG, Ascher MS, Eitzen E, Friedlander AM, Gerberding J, Hauer J, Hughes J, McDade J, Osterholm MT, , Parker G, Perl TM, Russell PK, Tonat K, Working Group on Civilian Bio-defense. Anthrax as a biological weapon, 2002: Updated recommendations for management. Journal of the American Medical Association 2002; 287:2236-52.

    United States Army Regulation 40-562; Navy Bureau of Medicine & Surgery Instruction 6230.15; Air Force Joint Instruction 48-110; Coast Guard Commandant Instruction M6230.4E. Immunizations & Chemoprophylaxis. Washington, DC, 1 November 1995.

    Wiesen AR, Littell CT. Relationship between pre-pregnancy anthrax vaccination and pregnancy and birth outcomes among U.S. Army women. Journal of the American Medical Association (JAMA) 2002; 287:1556-60.

  6. Have any studies revealed birth defects among babies born to women who received anthrax vaccine during their pregnancy?

    A recent study by the Department of Defense (DoD) Center for Deployment Health Research with the Naval Health Research Center and the National Center for Birth Defects and developmental Disabilities indicated that women who received anthrax vaccinations during their first trimester of pregnancy could have a slightly higher risk of birth defects than women receiving anthrax vaccine at other times before or after the first trimester.  The study is still under review. Results are pending.

  7. Are the chances for birth defects increased if both parents have received anthrax vaccination?
    There is no evidence in the above mentioned study to indicate that anthrax vaccination in both parents increases the risk for birth defects in babies born to those parents.

  8. I don't have any children now, but hope to one day and I'm currently taking the anthrax vaccination. Will this vaccination cause birth defects in my future children?
    There is no increased risk of birth defects when receiving anthrax vaccination before becoming pregnant. If you are trying to become pregnant or think you may be pregnant, be sure to request a pregnancy test. Inactivated vaccines are generally considered safe in pregnancy.

  9. I'm scheduled to start/restart my anthrax vaccination series, but I want to start trying to get pregnant. Should I delay getting pregnant?
    There is no increased risk of birth defects when receiving anthrax vaccination before becoming pregnant. If you are trying to become pregnant or think you may be pregnant, be sure to request a pregnancy test. DoD policy is to temporarily exempt women who are pregnant.

  10. Why is anthrax vaccine not contraindicated with breast-feeding?
    Women who are breast-feeding may safely receive any vaccine. As an inactivated vaccine, anthrax vaccine contains no living or dead organisms and is non-infectious. No ill effects to the infant are anticipated through breast-feeding. As recommended by the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention (CDC), there is no need to interrupt breast-feeding (lactation) for inactivated vaccines.

  11. I got the anthrax vaccine and then found out that I am pregnant. What should I do?
    You should discuss your anthrax vaccination with your healthcare provider and/or obstetrician. As with any pregnancy, you should receive regular prenatal care. the IHB is available to discuss the latest information about pregnancy and adverse events research. Please visit our pregnancy page or contact the IHB with further questions.

  12. Will anthrax vaccine affect my ability to have children?
    Current research shows that anthrax vaccine does not affect pregnancy rates. Please contact the IHB if you are interested in this research or if you would like to discuss this issue with one of our healthcare providers.