Vaccine Ingredients - Antibiotics

Antibiotics are used to prevent bacterial contamination during manufacture. Most are removed during the vaccine purification process, but trace quantities remain in some vaccines. 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). 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; ppm = parts per million; ppb = parts per billion

Measles, mumps, rubella (MMR®)

Quantity Neomycin (per dose): 0.025 mg

Measles, mumps, rubella, varicella (ProQuad®)

Quantity Neomycin (per dose): .005 mg to < 0.016 mg (depending on storage requirements)

Meningococcal B Vaccine (Bexsero®)

Quantity Kanamycin (per dose): < 0.00001 mg

Varicella [chickenpox] (Varivax®)

Quantity Neomycin (per dose): Trace quantities

Rabies (Imovax®, RabAvert®)


  • Quantity Neomycin (per dose): ≤ 0.15 mg


  • Quantity Neomycin (per dose): < 0.001 mg
  • Quantity Chlortetracycline (per dose):  0.0002 mg
  • Quantity Amphotericin B (per dose): 0.00002 mg


Some influenza vaccines contain no antibiotics and others contain one or more of the following:

  • Quantity Neomycin (per dose): < 0.00002 mg – 0.000062mg
  • Quantity Polymyxin B (per dose): < 0.011mg
  • Kanamycin (per dose): < 0.00003 mg
  • Gentamicin (per dose): < 0.00015 mg

Polio (IPOL®)

  • Quantity Neomycin (per dose): 0.000005 mg
  • Quantity Streptomycin (per dose): 0.0002 mg
  • Quantity Polymyxin B (per dose): 0.000025 mg

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


  • Quantity Neomycin (per dose): ≤ 0.00000005 mg
  • Quantity Polymyxin B (per dose): < 0.00000001 mg

Pentacel and Quadracel

  • Quantity Neomycin (per dose): < 0.000000004 mg
  • Quantity Polymyxin B (per dose): < 0.000000004 mg

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

  • Quantity Neomycin (per dose): 0.00000005 mg
  • Quantity Polymyxin B (per dose): < 0.00000001 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


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 December 18, 2019

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.