Testing vaccines – another anti-vaccine myth requiring debunking

There are so many myths, tropes, and memes pushed by the anti-vaccine religion that it’s almost a full-time job to keep up with it all. One of the most ridiculous is that vaccines aren’t tested, especially in clinical trials. This is ridiculous on so many levels, the most important of which is that testing vaccines are critical to receiving regulatory approval across the world.

The anti-vaccine religion believes 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 social media, and individuals with no research background hold this particular belief as if it were the Truth™.

On the contrary, testing vaccines is a thorough process – each vaccine is tested for safety and effectiveness before being marketed. 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 testing vaccines myth

The anti-vaccine myth.

This meme says it all about what the anti-vaccine religion believes about testing vaccines.

Real science testing vaccines

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 (Hib)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 the 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 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 µg/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 (meningococcal C conjugate vaccine) 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.”
  • 23-valent pneumococcal vaccine. “The 23-valent pneumococcal polysaccharide vaccine prevented pneumococcal pneumonia and reduced mortality from pneumococcal pneumonia in nursing home residents.”
  • HPV vaccine. “Quadrivalent HPV vaccine prevents infection with HPV-6, 11, 16, and 18 and the development of related external genital lesions in males 16 to 26 years of age.”

Professor Dorit Rubinstein Reiss previously reviewed the whole myth about vaccines and placebo controls. She concluded that “vaccines are carefully studied and tested in controlled studies and clinical trials, using valid controls.”

Ethics of placebo controls in testing vaccine

Anti-vaccine zealots often make an argument that every vaccine isn’t tested using a double-blind, placebo-controlled study. Although many new vaccines are tested in that way, it’s highly unethical to do so with currently available vaccines.

A proper double-blind study would include two arms – the first one would contain the vaccine, and the second one would contain a placebo-control, which could have some ingredients of the vaccine, but not the antigen. No one, the doctor, the patients, or the pharmaceutical company knows which patient is getting what. Only at the end of the trial, the results are unblinded, meaning the researchers get to know who got what. Just to be clear, a patient doesn’t get to choose which arm they want – that would bias the results and make it pretty much useless.

Now back to ethics. Let’s say you want to test a vaccine like MMR, which has multiple years of use, in a double-blind clinical trial. The ethical issue becomes that you are intentionally placing the placebo-controlled group in harm’s way since they are at risk of contracting measles, mumps, and rubella. No institutional review board, the ethics committee of universities and hospitals which must clear all clinical trials. They would never approve of any study that would put the placebo or test group at risk of serious dangers.

This point seems to be missed by the anti-vaccine groups. So let me repeat it – it is highly unethical to intentionally not vaccinate a group and increase their risk to vaccine-preventable diseases.

The anti-vaccine people will then say, “we’ll volunteer our children for the placebo group.” That then bias the results significantly, and it would defeat the whole purpose of a double-blind clinical trial.

Now testing vaccines can include the gold standard clinical trial. According to the World Health Organization guidance on vaccine clinical trials, there are conditions when placebos are ethical:

Placebo use in vaccine trials is clearly acceptable when (a) no efficacious and safe vaccine exists and (b) the vaccine under consideration is intended to benefit the population in which the vaccine is to be tested.

Those conditions are met generally with a brand new vaccine, which would mean that no vaccine currently exists and that it is intended to benefit the population.

In addition, the anti-vaccine zealots frequently ignore the testing vaccines using large, case-control and cohort epidemiological studies. If they are well designed and large (many include millions of patients), they can be powerful evidence in support of the safety and effectiveness of vaccines.


The myths of testing vaccines have invaded the dialogue about the safety and effectiveness of vaccines. However, they are generally false. Worse yet, the demands of the anti-vaccine forces would force researchers to employ unethical, and ultimately impossible, methods that would not pass the scrutiny of an ethics review.

Moreover, most new vaccines were tested against placebo controls. Many old vaccines, during their clinical trials, were tested against placebo controls. And there are literally hundreds of massive epidemiological studies that constantly monitor the safety and effectiveness of all vaccines. And signals that there are issues are rarely observed.

So when it comes to testing vaccines – we have our children covered, despite the claims of the anti-vaccine woo-meisters. But they rarely get anything right.

Editor’s note: This article was originally published in September 2012. It has undergone extensive copyediting, updating, and broken link fixing. 

Key citations:

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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!