Vaccine Ingredients – Formaldehyde

Concerns about safety have focused on formaldehyde in part because high concentrations of formaldehyde can damage DNA (the building block of genes) and cause cancerous changes in cells in the laboratory. Although formaldehyde is diluted during the manufacturing process, residual quantities of formaldehyde may be found in several current vaccines (see table below). However, formaldehyde does not appear to be a cause of cancer in humans. Further, animals exposed to large quantities of formaldehyde (a single dose of 25 mg/kg or chronic exposure at doses of 80-100 mg/kg/day) do not develop malignancies. (One kilogram [kg] is equal to 2.2 pounds.)

The average quantity of formaldehyde to which a young infant could be exposed at one time may be as high as 0.2 mg (see table below). This quantity of formaldehyde is considered to be safe for two reasons:

  • Formaldehyde is essential in human metabolism and is required for the synthesis of DNA and amino acids (the building blocks of protein). Therefore, all humans have detectable quantities of natural formaldehyde in their circulation (about 2.5 ug of formaldehyde per ml of blood). Assuming an average weight of a 2-month-old of 5 kg and an average blood volume of 85 ml per kg, the total quantity of formaldehyde found in an infant's circulation would be about 1.1 mg, a value at least five times more than the amount an infant would be exposed to in vaccines.
  • Quantities of formaldehyde at least 600 times more than the amount contained in vaccines have been given safely to animals.

Formaldehyde content of vaccines licensed for use in the United States

Td (adult)/ DT

Quantity per dose: ≤ 0.02 mg - 0.1 mg

DTaP (Daptacel®, Infanrix®, Tripedia®)

Quantity per dose: ≤ 0.1 mg

DTaP-Hep B IPV (Pediarix®)

Quantity per dose: ≤ 0.1 mg

Hepatitis A (Havrix®, Vaqta®)

Quantity per dose:
Havrix - ≤ 0.05mg (pediatric), ≤ 0.1 mg (adult)
Vaqta - 0.004 mg (pediatric), 0.008 mg (adult)

Hepatitis A - Hepatitis B (Twinrix®)

Quantity per dose: ≤ 0.1 mg

Hib-Hepatitis B (Comvax®)

Quantity per dose: < 0.0004 mg

Polio (IPOL®)

Quantity per dose: ≤ 0.02 mg

Japanese encephalitis vaccine (JE-Vax®)

Quantity per dose: < 0.2 mg

Tdap (ADACEL®, Boostrix®)

Quantity per dose:
ADACEL - < 0.005 mg
Boostrix - < 0.1 mg

Influenza (Fluarix®, FluLaval®, Fluzone® - intradermal)

Quantity per dose:
Fluarix - ≤ 0.005 mg
FluLaval - < 0.025 mg
Fluzone intradermal - < 0.02 mg


Epidemiology of chronic occupational exposure to formaldehyde: report of the Ad Hoc panel on health aspects of formaldehyde. Toxicol IndHealth. 1988;4:77-90.

Goldmacher VS, Thilly WG. Formaldehyde is mutagenic for cultured human cells. Mutat. Res. 1983;116:417-422.

Heck H, Casanova-Schmitz M, Dodd PB, et al. Formaldehyde (CH2O) concentrations in the blood of humans and Fischer-344 rats exposed to CH2O under controlled conditions. Am Ind Hyg Assoc J. 1985;46:1-3.

Huennekens FM, Osborne MJ. Folic acid coenzymes and one-carbon metabolism. Adv Enzymol. 1959;21:369-446.

Natarajan AT, Darroudi F, Bussman CJM, van Kesteren-van Leeuwen AC. Evaluation of the mutagenicity of formaldehyde in mammalian cytogenetic assays in vivo and in vitro. Mutat. Res. 1983;122:355-360.

Ragan DL, Boreiko CJ. Initiation of C3H/10T1/2 cell transformation by formaldehyde. CancerLett. 198113:325-331.

Til HP, Woutersen RA, Feron VJ, et al. Two-year drinking-water study of formaldehyde in rats. Food Chem Toxicol. 1989;27:77-87.

Reviewed by Paul A. Offit, MD on November 06, 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.