Vaccines aren’t tested – myth vs. science (updated)

There are so many silly memes that have arisen from the vaccine deniers, most of which have been thoroughly debunked. Everything from the well-worn (and worn-out) “vaccines cause autism” fable, which I have quashed here, to the “these diseases aren’t dangerous”, which, of course, couldn’t be farther from the truth.

One of the more annoying of the tales pushed by the vaccine refusers is that vaccines aren’t tested thoroughly before being used on unsuspecting infants. I do not know where this started, or why it started, but like much in the anti-vaccination world, it really doesn’t matter. It just passes from one person to another across google, and individuals with no research background hold this particular belief as if it were the Truth™.

Not only are vaccines thoroughly tested for safety and efficacy before being marketed, they also are rigorously tested in various combinations with other vaccines. And I’m not Cherry Picking a few articles to support my point of view, unless by cherry-picking you mean I’m picking the best articles from the highest quality journals in medicine.

The Myth


The anti-vacccine myth.

This meme says it all about what the anti-vaccination cult believes.

Real Science

Yes, our children do deserve better, and that’s why there are so many studies that do test vaccines in clinical trials with other vaccines. Below are just a sample of those studies:

  • Hexavac with Hepatitis A–”A schedule of two doses of HA (hepatitis A) vaccine, 6 months apart beginning at 6 months of age is highly immunogenic and well tolerated when administered alone or concomitantly with HV vaccine or HEXAVAC (diphtheria, tetanus, 2-component acellular pertussis, inactivated poliomyelitis vaccine, Haemophilus influenzae type b conjugated to tetanus protein and hepatitis B) at 6 and 12 months of age.”
  • Hexavalent vaccine with Rotateq–”In this study, concomitant administration of PRV (pentavalent rotavirus vaccine) with hexavalent vaccine was well tolerated and the immune responses to the antigens of the hexavalent vaccine were noninferior when compared with those of the control group. In addition, PRV was immunogenic when administered concomitantly with hexavalent vaccine.”
  • DTaP with Hib–”Mixing DTaP and Hib (Haemophilus influenzae type b)  vaccines for primary immunization caused a decrease in anti-Hib antibody response, although after primary immunization as after booster doses, all subjects showed antibody concentrations considered to be protective for invasive Hib disease. Mixing of the vaccines did not result in increased reactogenicity.”
  • PCV-13 with all infant vaccines–”PCV13 (13-Valent pneumococcal conjugate vaccine) will be as effective as PCV7 in the prevention of pneumococcal disease caused by the 7 common serotypes and could provide expanded protection against the 6 additional serotypes. The PCV13 safety profile was comparable to that of PCV7.”
  • MMR and Varicella–”The immunogenicities of M-M-RvaxPro (MMR) and VARIVAX (varicella or chickenpox vaccine) administered by the intramuscular route were comparable with those following subcutaneous administration, and the tolerability of the two vaccines was comparable regardless of administration route. Integration of both administration routes in the current European indications for the two vaccines will now allow physicians in Europe to choose their preferred administration route in routine clinical practice.”
  • PCV-7 with MMR, Hib and Varicella–”The immune response to MMR, Hib and varicella vaccines, when administered concurrently with a 4th (booster) dose of PCV7, was noninferior to that of these vaccines when given without PCV7. These results support concomitant administration of PCV7 with MMR, varicella and Hib as part of the recommended immunization schedule for children 12-15 months of age.”
  • Pediarix with Hib and Infanrix-hexa–”Both administrations of the candidate vaccine were found to be safe, immunogenic, and well tolerated. Although anti-PRP geometric mean antibody concentrations and the percent of subjects achieving the 1 microg/mL seroprotective level were lower after the mixed administration, they were in the range seen with monovalent Hib vaccines or with other DTaP-based/Hib combinations licensed in some European countries. Therefore both administrations have the potential to simplify childhood immunization.”
  • New Hib with all infant vaccines–”PHiD-CV (Haemophilus influenzae protein D conjugate vaccine) and MMRV vaccine can be coadministered without compromising the safety and immunogenicity profiles of either vaccine.”
  • MMR with Varicella–”Varicella vaccine does not appear to interfere with measles, mumps, or rubella seroconversions as indicated by this and previously published studies. Seroconversion rates were similar at all time points tested for measles, mumps, and rubella in the described studies. Varicella vaccine does not appear to interfere with measles, mumps, or rubella seroconversions as indicated by this and previously published studies. Seroconversion rates were similar at all time points tested for measles, mumps, and rubella in the described studies.”
  • MMR-V with Hib-HepB–”The immunogenicity data support concomitant administration of MMRV with Hib/HepB. Limited data from an exploratory analysis indicate that MMRV can be administered concomitantly with DTaP. Concomitant administration of MMRV, Hib/HepB and DTaP is well-tolerated.”
  • Meningococcal-C with Hep B and Pentacel–”The meningococcal C conjugate vaccine can be safely and effectively administered at the same visit as the other vaccine antigens routinely given to infants in Canada.”
  • Pentacel with PCV-7–”The use of DTaP-IPV (polio)-Hib and the 7VPnC (pneumococcal) vaccine was safe, well-tolerated and immunogenic when given concomitantly at age 2, 3 and 4 months or when given separately with 7VPnC as a catch-up vaccination at age 6, 7, 8 months and as a concomitant booster immunization at age 11-15 months.”
  • Concomitant use of rotavirus vaccine with other vaccines. “ In this study, antibody responses to the concomitantly administered vaccines were generally similar in PRV and placebo recipients. PRV was efficacious and well tolerated when given concomitantly with pediatric vaccines licensed in the United States.”
  • Meningococcal vaccine with other childhood vaccines. “4CMenB is immunogenic in infants and children aged 12 months with no clinically relevant interference with routine vaccines, but increases reactogenicity when administered concomitantly with routine vaccines.”
  • DTaP injected with MMRV. “The vaccine was well-tolerated and can be confidently used as a booster dose in pre-school children.”
  • Multiple vaccinations are not associated with asthma. “There is no association between diphtheria, tetanus and whole cell pertussis vaccine, oral polio vaccine or measles, mumps and rubella vaccine and the risk of asthma.”

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I’ve just presented a smattering of studies that show vaccines, when used in combination with other infant vaccines, are safe and generally effective. Every vaccine that’s used in the US, Europe, Japan, Australia, Canada, and anywhere else that follows the same regulations as those regions, is tested thoroughly for safety. Don’t let this myth confuse you, because real scientific evidence doesn’t support the myth that vaccines aren’t tested.

Vaccines save lives and the evidence support that claim.
Editor’s note: This article was originally published in September 2012. It has been completely revised and updated to include more comprehensive information, to improve readability and to add more relevant research.

Dorit Rubinstein Reiss has written a broader analysis of some of the clinical trial myths and tropes of the anti-vaccine activists

Key citations:


The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor
Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!