Childhood vaccine controversies: the myths, the facts and the uncertainties

by Dr Adli Ali

Vaccine controversies and anti-vaccine movements are not something new. They began some 90 years ago in the early 20th century, even before the term “vaccination” was formally used. Let us now revisit what we may consider to be the 7 most scientifically relevant controversial issues relating to “vaccines” and “vaccination” and explore the facts and verdicts for each of these issues.

Controversy 1: Vaccines cause autism

Verdict: MYTH

This “myth” was based on an article published in 1998 in The Lancet, written by Andrew Wakefield, a British surgeon, suggesting that the measles, mumps and rubella (MMR) vaccine increased autism incidences among British children [1]. This “infamous” article and his claim on the causal-relationship between vaccines and autism that ended up being discredited created a widespread fear among the public. Up until now, none of the numerous subsequent studies conducted were able to prove Dr. Wakefield’s claim and no scientific evidence has proven any possible link between the MMR vaccine and autism [2, 3, 4]. The article was eventually deemed flawed and retracted by The Lancet based on the serious procedural errors, undisclosed financial conflicts of interest, and ethical violations [5]. This controversy will always be a major myth in the vaccine world, hence, is officially referred to as the most damaging medical hoax of the century.

Figure 1: Reduction of measles cases and death upon measles vaccine introduction in 1968 in England and Wales (Data source: Public Health of England [17])
Figure 1: Reduction of measles cases and death upon measles vaccine introduction in 1968 in England and Wales (Data source: Public Health of England [17])
Controversy 2: Vaccines contain mercury and are damaging to body, leading to autism

Verdict: MYTH

Vaccines did contain Thiomersal, an organic mercury-containing compound, which was used in small amounts previously as antifungal preservative in some multi-doses vaccines. The amount used was significantly below the acceptable level considered tolerable by the World Health Organisation (WHO), and had evidently proven to be safe. Nonetheless, as a precautionary principle, Center for Disease Control (CDC) had directed removal of thiomersal from all childhood vaccines in 1999 [6]. Concerns on Thiomersal could have been responsible for autism was disapproved based on the fact that no causal relationship was ever documented, and despite current removal of thiomersal-based vaccines, the steady increase in incidences of autism is maintained [7].

Controversy 3: Some vaccines are not Halal


Illustration by Mohd Arshad.

Some vaccines use porcine-based-enzymes in their production, creating concerns on the “halal”ness of those vaccines. However, despite the fact that these enzymes are used in some of the processes of the vaccine manufacturing, the Islamic fatwa committee has allowed the usage of these vaccines. This is based on several Islamic principles in dissecting the issue. On the “halal”ness of the vaccine product itself, the concept of the “tiny amount” of enzymes added to the huge quantity of vaccine solution produced, in line with the concept of “suci” or “pure element” in Islam. Secondly, the removal of the used enzymes in the final production is also parallel to the concept of “cleanliness and pure element” in Islam, hence making the final product as “not containing” any of the “non-halal” elements through the principle of look, smell and taste. Finally, based on the crucial need of using the vaccine in disease prevention in situations whereby we do not have other “purely halal” alternatives, Islamic scholars have ruled that the use of this vaccine may be allowed in accordance to a ruling based on the concept of “dharurah” or emergency situations. However there exist some differences of opinion on this matter, whereby the more strict scholars cannot accept this new “law” based on “ijma” or “agreements” of scholars, particularly in relation to the “halal” concept [8].


Controversy 4: Human foetuses are aborted to produce vaccines


Research development and production of vaccines, especially in virus-based-vaccines, require culturing of the virus in specific human cells. The statement that human foetuses were aborted to produce vaccine is untrue, as in the development process of vaccines, commercial-laboratory produced human cell-line culture are being used [9]. Nonetheless, historically, these commercially grown cells were harvested through intentional medically-sacrificed human fetuses, approved and monitored strictly by ethical bodies, and a few decades ago, this was done purely for the need of the scientific research [10, 11]. No subsequent abortion was performed thereafter for any other scientific purposes. The usage of these foetus cell lines is extensive, extending to many different fields of the sciences, not just vaccine research and development.

Controversy 5: Natural protection is adequate and safer, vaccination is just redundant

Verdict: PARTIAL FACT      

Natural infection does provide lifelong immunity against certain infections. However, in the case of most vaccine-preventable diseases, the idea that natural infection is safer and adequate is dangerously untrue. Vaccine-preventable infections are proven to cause significant health problems, such as neurological side effects (or sequelae) from Hemophilus influenza meningitis and birth defects from maternal rubella infection, and fatality. In some organisms, a single naturally occurring infection may not be adequate to prevent the next infection and may lead to more severe disease, such as in the case of Dengue fever. Vaccination does not only prevent infection, but also prevents the disease associated with natural infection, i.e. cervical cancer through Human Papillomavirus (HPV) vaccination and hepatitis through Hepatitis B vaccination. As many organisms also have several serotypes, vaccination is not redundant in naturally protected individuals, as the vaccine may provide protection against other serotypes and enhance immune response towards the naturally protected serotype.

Controversy 6: Too many childhood vaccinations, immune system overloaded

Verdict: MYTH

Our immune system is just remarkable. Without us even realising it, the immune system is constantly exposed and able to prevent infections competently. Giving several vaccines at the same time is shown to be safe, immunologically effective, logistically and economically efficient. Concerns on overloading the immune system are false and based on a non-immunological assumption. It is crucial that protection is achieved by a certain point of time in a child’s life. This is based on the epidemiological knowledge on the prevalence and likeliness to encounter the infection. Combination vaccines also means less injections which lead to less parental anxiety and stress on the child [12].

Controversy 7: Vaccination is not without side effects

Verdict: FACT

As with any other drugs or interventions, vaccination is, of course, not without side effects. Most of them are mild and tolerable side effects such as fever, flu-like illness, and pain and/or redness at local injection site pain. These known side effects are clearly stated in the information sheets and well-tolerated in many. Development of vaccines, as with most drugs, involves several phases, and safety is among the first phase requirement before the candidate vaccine even goes to the clinical trial phase. Nonetheless, there were incidences where serious and unexpected complications occurred and only recognised after the wide usage of the vaccine within the population. One example is in the case of the rotavirus vaccine, Rotashield. This vaccination causes an increased incidence of intussusception among toddlers, leading to its retraction from usage soon after it was noticed [13]. Tight surveillance is in place to monitor the safety of any drug and vaccine, as experience in different wider population might reveal new entities not discovered during the clinical trials.

There are several other arguments, not discussed in this article, that are being exploited by the anti-vaccine movements which are based on sentiment and false-beliefs [14]. Faulty arguments that we do not need vaccination for measles since the infection is no longer a major problem, has led to the current measles outbreak in several countries [15, 16]. It is important for scientists, physicians and patients to know the advantages and the limitation of vaccines. Vaccination has come a long way since its discovery and had changed its primary role in infection prevention, to even therapeutic and disease prevention now. The new technology embedded in vaccine development, using an antigenic part of the pathogen (subunit vaccine) or the pathogen’s DNA materials (DNA vaccine) may not just come with less side effects, but possibly a more effective vaccine and also the answer to many more diseases that need to be tackled where a vaccine is yet to be developed.

About the Author

Dr Adli Ali is a medical academician and clinical scientist, passionate about exploring the mysterious and fascinating world of immunology. A paediatrician at heart and by training, he also loves the science of fantastic gourmet and the art of travelling the world. Currently furthering his sub-specialisation at University of Oxford, he is ambitious and determined to develop and enhance the translational clinical and collaborative medical research in the region. Find out more about Adli by visiting his Scientific Malaysian profile at

This article first appeared in the Scientific Malaysian Magazine Issue 12. Check out other articles in Issue 12 by downloading the PDF version for free here: Scientific Malaysian Magazine Issue 12 (PDF version)


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