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5th Annual Advocacy Project: ImmuneWise Section on Medical Students, Residents, and Fellowship Trainees 2009-2010 “What About Mercury?” Vaccine Components and Manufacturing Process Vaccine Components • • • • • • • • • Live viruses Killed viruses Purified viral proteins Inactivated bacterial toxins Bacterial polysaccharides Preservatives (eg, thimerosal) Adjuvants (eg, aluminum salts) Additives to stabilize live, attenuated viruses Residual substances from manufacturing process Offit PA and Jew RK. Addressing parents’ concerns: Do vaccines contain harmful preservatives, adjuvants, additives, or residuals? Pediatrics. 2003; 112(6):1394-1401 Preservatives • Required component of vaccines since 1930s – 1916 Typhoid Vaccine contaminated with Staphylococcus aureus led to 4 deaths, 68 serious systemic infections and 26 kids with local abscesses – Many other reports of bacterial and fungal contamination • 3 were licensed in US – Thimerosal – Phenol – 2-Phenoxyethanol Thimerosal • Removed from all multi-dose vaccines by 2001 by the FDA Modernization Act of 1997 • Previously in DTaP, Hep B, Hib – For a total of 187.5 micrograms mercury by 6 months • Thimerosal contains ethylmercury, which is excreted faster than methylmercury Exposure limits of methylmercury in micrograms by 6 months of age by % Body Weight Agency 5% Body Weight 50% Body Weight 95% Body Weight EPA 65 89 106 ATSDR 194 266 319 FDA 259 354 425 Thimerosal • Current thimerosal containing vaccines: – Influenza – Meningococcal – Japanese Encephalitis – Pneumococcal polysaccharide (Pneumovax) – Diphtheria-Tetanus Thimerosal • Studies published to date have not shown thimerosal exposure to be harmful – 2004: UK prospective cohort study of >14,000 infants showed no convincing evidence that thimerosal has deleterious effect on neurological or psychological outcome (Heron and Golding) – 2004: UK retrospective cohort study of 110,000 children found that with the exception of tics, there was no evidence that exposure to thimerosal through DTP/DT vaccines causes neurodevelopmental disorders (Andrews et al.) – 2007: CDC and Vaccine Data Safety Network published retrospective cohort study on neuropsychological outcomes in 1047 children aged 7-10 years old and found no deleterious effects from early thimerosal exposure (Thompson et al.) • Vaccine Data Safety Network – Large case-control study of autism and thimerosal exposure currently in data collecting phase Adjuvants • Enhance the immune response – Enhance antigen uptake by antigen presenting cells – Activate antigen presenting cells – Induce production of cytokines and complement • Aluminum salts – First added to diphtheria and tetanus in the 1930s – Benign Adverse Reactions – mostly erythema – Aluminum quantities • Breast milk – 40 micrograms/liter • Formula – 225 micrograms/liter • Vaccines – 125 micrograms – 625 micrograms/dose – Mouse studies established safety of aluminum in humans to be <62 mg/kg/day Adjuvants – Vaccines Containing Aluminum Additives • Stabilize vaccines from heat and cold • Prevent adherence to vials • Types of additives – Sugars (sucrose, lactose) – Amino acids (glycine, glutaminic acid) – Proteins (gelatin, albumin) • Known adverse events – Immediate type hypersensitivity to gelatin Additives – containing gelatin Vaccine Trade Name Manufacturer Dtap Tripedia Aventis Pasteur Influenza Fluzone Aventis Pasteur Measles Attenuvax Merck and Co Mumps Mumpsvax Merck and Co Rubella Meruvax II Merck and Co Measles, rubella MRVAX II Merck and Co Mumps, rubella Biavax II Merck and Co MMR MMR II Merck and Co Varicella Varivax Merck and Co Rabies Rabavert Chiron Japanese encephalitis JE-Vax Aventis Pasteur Additives – albumin & infectious risks • Albumin derived from human serum derived from human blood • Theoretical risk of infection • FDA requirement that albumin derived from screened donors • No viral diseases have ever been associated with the use of human albumin Additives – containing albumin Vaccine Brand Name Manufacturer Measles Attenuvax Merck and Co Mumps Mumpsvax Merck and Co Rubella Meruvax Merck and Co MMR MMR II Merck and Co Additives – containing bovine Derived products • Gelatin, glycerol, enzymes, serum, amino acids are derived from cows • Creutzfeld-Jacob Disease – Caused by prions – No association of CJD to blood products – Prions not found in cow hooves (used to make gelatin) – Epidemiologic evidence does not support vaccines as a cause for CJD in the UK manufacturing residualsInactivating agents • Formaldehyde – Influenza, Polio, Diphtheria, Tetanus – Human blood contains 10x more than any one vaccine – Natural intermediate in synthesis of amino acids, purine, and thymidine – Animal and human studies do not show increased risk for malignancies after formaldehyde exposure • Beta-propriolactone – Rabies • Glutaraldehyde – Acellular pertussis manufacturing residualsantibiotics • Theoretical risk of immediate-type hypersensitivity to residual antibiotics (used to prevent contamination during manufacturing) • Antibiotics used: Neomycin, streptomycin, polymyxin B, chlortetracycline, amphotericin – Only neomycin is associated with immediate-type hypersensitivity but no cases documented at this time – Risk of delayed-type hypersensitivity but not a contraindication manufacturing residualsEgg proteins • Egg allergies occur in 5% children with atopy • Vaccines manufactured in chick embryos – Influenza – contraindicated if egg allergy, follow strict protocol if asthma and egg allergy – Yellow fever – Measles and mumps – very small quantity – egg allergy in not a contraindication references Studies on Thimerosal Heron J and Golding J. Thimerosal exposure in infants and developmental disorders: A prospective cohort study in the United Kingdom does not support a causal association. Pediatrics. 2004; 114(3):577-583 Andrews N et al. Thimerosal exposure in infants and developmental disorders: A retrospective cohort study in the United Kingdom does not support a causal association. Pediatrics. 2004; 114(3) 584-591 Thompson WW et al. Early thimerosal exposure and neuropsychological outcomes at 7 to 10 years. NEJM. 2007; 357(13): 1281-1292. Other Readings Offit PA and Jew RK. Addressing parents’ concerns: Do vaccines contain harmful preservatives, adjuvants, additives, or residuals? Pediatrics. 2003; 112(6):1394-1401 AAP Media – Thimerosal Speaking Points Sears RW. The Vaccine Book. McCarthy, J. Louder Than Words.