Vaccine Ingredients - Antibiotics

Antibiotics are present in some vaccines and are used to prevent bacterial contamination during manufacture. Because antibiotics can cause severe allergic reactions in children (like hives, swelling at the back of the throat, and low blood pressure), some parents are concerned that antibiotics contained in vaccines might be harmful. However, the antibiotics most likely to cause severe allergic reactions (e.g., penicillin, cephalosporins and sulfa drugs) are not contained in vaccines.

Antibiotics used during vaccine manufacture include neomycin, polymyxin B, streptomycin and gentamicin. Only minute quantities remain in vaccines (see table below). However, these small quantities of antibiotics have never been clearly found to cause severe allergic reactions. Therefore, the possibility that the trace quantities of antibiotics contained in vaccines cause severe allergic reactions remains, at best, theoretical.

Antibiotic content in vaccines licensed for use in the United States

mg = milligrams; ppb = parts per billion

Measles, mumps, rubella (MMR®)

Quantity Neomycin (per dose): 0.025 mg

Measles, mumps, rubella, varicella (ProQuad®)

Quantity Neomycin (per dose): < 0.016 mg

Varicella [chickenpox] (Varivax®)

Quantity Neomycin (per dose): Trace quantities

Zoster [shingles] (Zostavax®)

Quantity Neomycin (per dose): Trace quantities

Rabies (Imovax®, RabAvert®)


Quantity Neomycin (per dose): 0.15 mg


Quantity Neomycin (per dose): < 0.001 mg

Influenza (Fluvirin®, Afluria®)


Quantity Neomycin (per dose): 0.025 mg
Quantity Polymyxin B: < 0.00375 mg


Quantity Neomycin (per dose): 0.000003 mg
Quantity Polymyxin B: 0.0000005 mg

Polio (IPOL®)

Quantity Neomycin (per dose): 0.000005 mg
Quantity Polymyxin B: 0.000025 mg

Diphtheria, tetanus, pertussis, polio (Kinrix®, Pentacel®)


Quantity Neomycin (per dose): 0.00000005 mg


Quantity Neomycin (per dose): < 0.000000004 mg

Diphtheria, tetanus, pertussis, hepatitis B, polio (Pediarix®)

Quantity Neomycin (per dose): 0.00000005 mg

Hepatitis A (Havrix®, Vaqta®)


Quantity Neomycin (per dose): < 0.00004 mg


Quantity Neomycin (per dose): < 10 ppb

Hepatitis A, hepatitis B (Twinrix®)

Quantity Neomycin (per dose): <0.00002 mg

Other antibiotics found in trace quantities include:

  • Kanamycin (<0.0003 mg in influenza vaccine called Agriflu®)
  • Gentamicin sulfate (< 0.0015 mg in influenza vaccines known as Fluarix® and Flumist®)
  • Streptomycin (.0002 mg in polio shot known as IPOL®)
  • Chlortetracycline (0.00002 mg in rabies vaccine known as RabAvert®)
  • Amphotericin B (0.000002 mg in rabies vaccine also in RabAvert®)


Goh CL. Anaphylaxis from topical neomycin and bacitracin. Aust J Dermatol. 1986 Dec;27(3):125-6.

Kwittken PL, Rosen S, Sweinberg SK. MMR vaccine and neomycin allergy. Am J Dis Child. 1993 Feb;147(2):128-9.

Leyden JJ, Kligman AM. Contact dermatitis to neomycin sulfate. JAMA 1979 Sep 21;242(12):1276-8.

MacDonald RH, Beck M. Neomycin: a review with particular reference to dermatological usage. Clin Exp Dermatol. 1983;8:249-258.

Yunginger JW. Anaphylaxis. Curr Prob Pediatr. 1992;22:130-146.

Reviewed by Paul A. Offit, MD on November 05, 2014

Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.