Vaccines have been heralded as one of the “major revolutions in the history of mankind”[1]. Yet there is a strong anti-vaccine campaign particularly targeting early-life vaccination, leading to more and more parents deciding not to vaccinate their children.

So who is right? What risks do vaccines pose and should we still be using them? The short answer is: unless they belong to a particular risk group, you should definitely vaccinate your children!

Refusing to do so can expose them and others to deadly diseases. Not that easily convinced? Then please read on.

A quick internet search or a browse on social media will expose you to a plethora of articles warning you about the evils of vaccines.

These generally focus on one or more of the following arguments:

The first is that we were fine before vaccines came along when everything was more natural; the second is that they are the product of a deal between governments the pharmaceutical industry to guarantee them a steady income to the detriment of our health; and finally, there is a whole range of claims regarding the dangers of vaccines and their side effects. Supposedly, since the diseases vaccines target have been eradicated or can be cured, we no longer need these vaccines.

Let’s start with the first: Is it true that our ancestors, who lived in a less medicated world were healthier than we are today?

Statistics show the contrary: the average life expectancy has risen dramatically from the age of around 35 to 65 worldwide over the last 200 years [1].

Although the oldest people are not much older today than they were in the stone age, we have seen a steep drop in childhood mortality. Before the 20th century, only one in four children used to reach the age of 20 [1].

The drop in childhood mortality coincides with the introduction of rigorous hygiene practices and modern medicine, in particular the invention of vaccines in the late 18th century.

Vaccines have led to the complete eradication of smallpox, and have almost eliminated diphtheria, tetanus, pertussis, measles, mumps and rubella [1]. New vaccines continue to be developed for diseases such as malaria, ebola and even cancer [2], and still prevent millions of deaths every year.

Being “natural” means facing these very natural and deadly diseases. Nature is not always kind, and we have plenty of reasons to fear it.

The second argument is also misleading. To be clear, I am by no means an advocate of the pharmaceutical industry. I personally believe that the current medical system, in which human health is tied to financial gains, is severely flawed.

Nevertheless, compulsory vaccination programs enforced by governments are not necessarily in the interest of the pharmaceutical companies. If anything, the pharmaceutical industry would gain more if we were to stop using vaccines.

Indeed, it has been calculated that vaccines have led to global savings of tens of billions of US dollars each year that would otherwise be spent on medication to treat the diseases that vaccines protect us from [3]. The interests of the pharmaceutical industry do conflict with those of the global population in some instances, though.

For example, companies focus on vaccines for diseases that affect more developed countries, which is more lucrative than selling vaccines for diseases like malaria, cholera or dengue, which affect people living in poorer countries. Between 1975 and 1997, 1233 new medicines were patented, only 1% of which were for tropical diseases [20].

Third and most worrying are rumours regarding the alleged side effects caused by vaccines that contain “toxic” ingredients. While vaccines can have rare but worrying side-effects, the majority of claims have no scientific basis. Lists of “toxic” ingredients I have found include things like glycerol (sugar alcohol, also used in commercial cookies), dog kidney (neither toxic, nor is it an ingredient of vaccines – viruses used in the vaccine are sometimes grown in animal cell cultures, which may be a kidney, and then extracted) and chicken egg (this one hardly needs explaining).

Others scare their readers by warning them that they are being injected with live viruses! This is not a reason to avoid vaccines. In fact, it is often precisely the way in which vaccines work: you are injected with a tiny amount of the – often dead or weakened – virus that causes a particular disease. This stimulates your immune system to generate the relevant defences against the virus, and because of the tiny dose, your body fights it off easily.

The next time you are exposed to the virus in a larger amount, the body will recognise it and fight it off immediately, keeping you healthy. I realise that being injected with a virus sounds scary, but your body is exposed to millions of microbes every day including many viruses that it fights off successfully.

One of the most widespread and destructive rumours was that the MMR (Measles-Mumps- Rubella) vaccine causes autism.

This idea stems from a paper by Andrew Wakefield and his co-authors in 1998, involving twelve children – a number far too low to draw any definite conclusions – which claimed to have found a link between the vaccine and autism [5].

The media outrage caused by the paper led to many further studies by different authors, involving many more patients, none of which found a link [6, 7, 8, 9, 10] .

Information later surfaced that Wakefield had received payment from a legal company seeking evidence against the vaccine and was found guilty of serious professional misconduct [12].

In 2010, the paper was finally fully retracted [13]. Sadly, in the mean-time, the damage had been done. Many parents had refused to vaccinate their children, leading to both measles and mumps epidemics, resulting in multiple deaths and permanent injuries.

Most damage was done in the UK where the voice of the media was especially loud. By 2008, however, the outbreaks had spread to other countries including the USA, Canada, Ireland, Austria, Italy and Switzerland [4].

This is not to say that vaccines never have any side-effects. For example, in the 1970s an association was found between a particular swine flu vaccine and Guillain-Barr ´e syndrome, which causes temporary paralysis.

The vaccine was removed from the market soon thereafter, and subsequent influenza vaccines have shown no such association [14].

This example demonstrates that there is a continuous and significant effort from scientists, governments and global organisations, such as the World Health Organization, to make sure that vaccines are as safe as possible.

Before becoming available in the market, new vaccines are subject to extensive testing, and are monitored for long periods of time once they are administered to the wider public. Because of such potential side-effects, if the disease is not particularly dangerous, vaccinating can be avoided.

This is often the case for influenza, which is probably only worth vaccinating against in certain high risk groups.

Misinformation and the resulting refusal to vaccinate not only put the unvaccinated person at risk, but can also lead to the loss of so-called “herd immunity”.

Herd immunity is achieved when enough people (typically around 90% but this number depends on the disease) are vaccinated, making the population as a whole immune [15]. If vaccination rates in a population drop below this percentage, the disease begins to spread.

It is important to mention that particular risk groups, such as people with immune system diseases (e.g. HIV) or the very young, should not receive certain vaccines. To keep these people protected, we need to make sure that we preserve herd immunity by keeping the percentage of unvaccinated people small. By refusing to vaccinate your children, you are selfishly taking up space in that precious small percentage and putting vulnerable people at risk.

In Egypt, vaccination rates are quite high [16], due to long-term government policies enforcing rigorous vaccination programmes. More recently, though, as more people are exposed to Western media and are striving for a more natural lifestyle, they have begun to follow a global trend to avoid vaccines. Although we have not yet faced this problem in Egypt, we should learn from the lessons of other countries – particularly where vaccination is not compulsory – which have recently been faced with deadly epidemics, such as those caused by the MMR scandal. Clearly then, unless a disease has been completely eradicated, we need to continue to vaccinate against it.

We must not forget how dangerous some of these diseases are: Earlier this year, the WHO declared a global emergency as the polio virus, which was near eradication in 2013, has once again become threatening.

Polio can infect the spinal cord, causing paralysis in one in every 200 cases and can lead to death within hours if paralysis affects the muscles used for breathing [17].

This recent epidemic has been particularly worrying in Syria (which had been polio-free for the last 14 years), where vaccination programmes have been prevented due to civil unrest [18].

Even measles can lead to serious complications, including severe retardation and blindness, and has a fatality rate of one in 3000 in the US, and up to 28% in developing countries, where patients are more likely to be suffering from malnutrition [19].

There is no doubt that the internet is a wonderful and indispensable tool, but the lack of a filter makes it quite a dangerous one. It is then up to you as an information consumer to do the filtering. In deciding what to believe, a good first step is to check for sources and citations. Many fraudulent articles include no citations whatsoever. You should also check some of the more suspect pieces of information. A quick search shows, for example, that a small dose of glycerol is no more dangerous than dihydrogen monoxide (also known as “water” – scared you for a moment?).

So before you start believing the scare-mongering articles online, which will endanger the lives of our children, check the recommendations of the World Health Organization.

If you do not trust them, then make the effort to do your own research. Look up the exact ingredients of a vaccine, and how they are used. Check the statistics reported in reputable medical journals on mortality and side-effects associated with taking the vaccine versus contracting the disease.

As certain diseases become rare, we lose our fear, resulting in a reluctance to vaccinate. Do we really need to relive these terrible diseases periodically to remind ourselves of the necessity to vaccinate? If we are not careful, the shortness of our collective memory and our inability to learn from others may lead us to sacrifice our children’s health.

Sara Mitri

Dr. Mitri is a research scientist working in the field of microbiology at the University of Oxford. After earning her PhD from the Ecole Polytechnique F´ed´ erale de Lausanne, she has worked at renowned universities including Harvard University and the University of Oxford.

References

[1] Rappuoli R, Mandl CW, Black S, De Gregorio E (2011) Vaccines for the twenty-first century society. Nature Reviews Immunology, 11:865-872.

[2] Pejawar-Gaddy S, Finn OJ (2008) Cancer vaccines: Accomplishments and challenges. Critical Reviews in Oncology/Hematology, 67:93-102.

[3] Ehreth J (2003) The global value of vaccination. Vaccine, 21:596?600.

[4] Editorial (2008) A case of junk science, conflict and hype. Nature Immunology, 9:1317.

[5] Wakefield AJ, et al. (1998) Ileal lymphoid nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children [retracted]. Lancet, 351:637-41.

[6] Black C, Kaye JA, Jick H (2002) Relation of childhood gastrointestinal disorders to autism: nested case control study using data from the UK General Practice Research Database. BMJ, 325:419-21.

[7] Taylor B, Miller E, Lingam R, Andrews N, Simmons A, Stowe J (2002) Measles, mumps, and rubella vaccination and bowel problems or developmental regression in children with autism: population study. BMJ, 324:393-6.

[8] Madsen KM, et al (2002) A population-based study of measles, mumps, and rubella vaccination and autism. New England Journal of Medicine, 347:1477-82.

[9] Honda H, Shimizu Y, Rutter M (2005) No effect of MMR withdrawal on the incidence of autism: a total population study. Journal of Child Psychology & Psychiatry, 46:572-9.

[10] The editors of the Lancet (2002) Time to look beyond MMR in autism research. The Lancet, 359:637.

[11] www.upworthy.com/16-years-ago-a-doctor-published-a-study-it-was-completelymade- up-and-it-made-us-all-sicker 4

[12] Transcripts of hearings of fitness to practise panel (misconduct) in the case of Wakefield, Walker-Smith, and Murch. GMC, 2010. vaccineswork.blogspot.co.uk/p/wakefield-transcripts-and-gmc-documents.html

[13] The editors of the Lancet (2010) Retraction – Ileal-lymphoid-nodular hyperplasia, nonspecific colitis, and pervasive developmental disorder in children. Lancet, 375:445.

[14] Bonhoeffer J, Heininger U (2007) Adverse events following immunization: perception and evidence. Current Opinion in Infectious Diseases, 20:237-246.

[15] Anderson RM, May RM (1990) Modern vaccines. The Lancet, 335:641-645.

[16] WHO and UNICEF immunization summary (2013). www.unicef.org/videoaudio/PDFs/EN-ImmSumm-2013.pdf

[17] Publication by the Center for Disease Control and Prevention. www.cdc.gov/vaccines/pubs/pinkbook/downloads/polio.pdf

[18] http://www.theguardian.com/global-development/2014/mar/28/un-polio-syria-iraqmost- challenging-history

[19] Perry RT, Halsey NA (2004) The Clinical Significance of Measles: A Review. Journal for Infectious Disease, 189:S4-S16.

[20] Sharma R (2000) AIDS vaccine research focuses on subtypes in developed world. BMJ, 321:787. 5