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5 Common Myths about vaccines

We live in an age of incredible luxury. Many people today have never encountered diseases that were once rampant and harmful – all thanks to vaccinations. Unfortunately, not everyone has access to life-saving immunisation due to their remote living conditions or socio-governmental situations. Moreover, some people opt not to vaccinate themselves or their children, even when vaccines are freely available.

There are many reasons that people cite for opposition to vaccinations. These can be philosophical, religious or concerns about safety. Anti-vaccination movements have been around since vaccines were first created. Today, the internet is flooded with a lot of confusing and contradictory information about vaccinations. The same arguments and misconceptions are seen over and over again.

Here are five of the most common myths and misconceptions around vaccines:

Polio vaccine | Unicef Guinea
Polio vaccine | Unicef Guinea
  • The majority of people who become infected with a disease are those who were vaccinated against it.

The implication behind this statement is that vaccinations have no effect since vaccinated people can still catch the disease. Like many treatments, vaccinations are not 100% effective in all cases. For example, one dose of the MMR (Measles, Mumps & Rubella) vaccine is 93% effective against measles, 78% effective against mumps, and 97% effective against rubella. (2) The protective effect increases with the second, follow-up MMR vaccination.

Unfortunately, some people who receive the vaccine will still catch the disease. A potential reason for this, is that the vaccinated person becomes infected with a mutated strain of the disease. Mutations in a disease allow it to bypass the bodies’ vaccine-provided antibodies and thus renders the vaccine ineffective. As vaccines only target a specific strain of the virus, they can protect us from some but often not all infections. Flu is a classic example of an illness that mutates extremely quickly and this is why it is recommended that people have a flu shot every year.

Overall, immunisation still significantly decreases the risk of infection and the amount of infections averted due to vaccination supports their continued use.  

 

Vaccines and the Autism Myth – Part 1 | Khan Academy Medicine

  • Vaccines cause autism.

Autism is a complicated condition, and scientists still do not know how it originates. It is suspected that there is both a genetic and an environmental component.

The paper that first suggested that MMR (measles, mumps, rubella) vaccinations caused autism in British children was published in 1997 by Andrew Wakefield. It has since been entirely discredited: Wakefield had undisclosed conflicts of interest and serious procedural errors. He had even filed a patent for his own vaccine that would compete with MMR. The paper was retracted, and Wakefield lost his medical license. The study has been repeated multiple times, and the results that Wakefield reported have never been replicated.

However, the conclusion he drew persists in the public arena despite being firmly discredited in the scientific field. Vaccinations occur all throughout a child’s development to adulthood. Autism is diagnosed from pre-school age onwards and as a result, it is easy to pin the cause of autism on vaccines whilst overlooking other environmental factors. There is simply no proven scientific link between vaccines and autism.

 

Injection | Dr PS Sahana Kadamtala Howrah via Photopin
  • Vaccines have harmful side effects

Vaccines are rigorously tested and have to adhere to strict standards before they are put out on the market. It is not unusual for some vaccines to produce a mild reaction in the patient: such as mild fever or a sore arm. This is the bodies’ immune system creating antibodies that can fight off the disease for real. These side effects, while present, are not considered harmful.

Whilst a subset of people who are vaccinated have these side effects, they are much less extreme than the diseases themselves. It is far more likely to be seriously harmed by a disease than the vaccine that prevents it. For example, polio can cause paralysis. Pertussis (whooping cough) can cause rib fractures from coughing. Mumps can cause infertility in men. The vaccines given to prevent these disease do not cause any of these side effects.

 

John Twohlg Syringe 2 | Flickr
  • Former common diseases were disappearing because of better hygiene, before we had vaccines.

The intent behind this statement is to suggest that modern sanitation, increased standards of living and better nutrition are sufficient to prevent the spread of diseases. It induces doubt that vaccinations are actually needed. Our increased standards of hygiene certainly play a role in preventing the spread of disease.

However, some diseases are infectious regardless of how clean we are. For example, in 2014, there were 23 different outbreaks of measles across the United States. One particularly large outbreak, where 383 people caught measles, was among a largely unvaccinated Amish community. (3) Many of the outbreaks across the states were associated with travellers who brought the disease from elsewhere.

Even first world standards of hygiene can’t protect the spread of some infectious diseases. However, if a large enough portion of the population are vaccinated, this can protect vulnerable people who are unable to receive vaccinations. For example, immunocompromised individuals and pregnant women are at high risk of infection and are unable to receive certain vaccines. If a vulnerable person’s community is up-to-date on their vaccinations then this can prevent the spread of infectious disease and protect a vulnerable person.

 

Vaccines protect you and the people around you | Centre for Disease Control (CDC)
  • Vaccine-preventable diseases have been virtually eliminated from my country so I don’t need to vaccinate

Thanks to vaccines, there are countries where diseases are extremely rare. However, these are still at epidemic levels in countries without vaccinations. Humans in general are mobile and when we travel we may unknowingly bring along a disease as an unwanted passenger. For example, when universities open, there tends to be a period of sickness as students from all around the world bring their local diseases to a social mixing pot.

Vaccinating also helps protect people who are unable to get vaccinated. Immunocompromised people (e.g. cancer patients undergoing radiation therapy or people infected with HIV) are unable to receive vaccines and are simply more vulnerable to these diseases. By vaccinating yourself, you are protecting these people by decreasing the chance of transferring harmful illnesses.

 

The graph below shows that there is a powerful relationship between vaccinations and reduction in cases of disease. There are examples of countries who stopped vaccinations for certain diseases and the number of cases increased.

In 1974 Japan, around 80% of children were receiving the pertussis vaccine. There were only 393 cases of pertussis in the entire country, and no deaths. Then there was a decrease in immunisation rates, to only 10% in 1979. That year, over 13,000 people caught whooping cough and 41 people died. Fortunately, the vaccination rates increased again and fewer people got sick.

 

It is interesting to see the power of vaccines with numbers. The following table shows how vaccinations have lead to the significant decrease in the following diseases:

Disease

Number of Annual Prevaccine Cases

20th Century*

Number of Annual Postvaccine Cases

2010

Reduction of Cases after Vaccine Introduction (in %)
Diphtheria 21,053 0 100%
Measles 530,162 55 99.90%
Mumps 162,344 6,584 95.90%
Pertussis 200,752 15,632 92.20%
Poliomyelitis, acute 19,794 0 100%
Poliomyelitis, paralytic 16,316 0 100%
Rubella 47,745 11 99.90%
Congenital rubella syndrome 152 1 99.30%
Smallpox 29,005 0 100%
Tetanus 580 41 92.90%
Hepatitis A 117,333 15,298 87%
Acute hepatitis B 66,232 13,169 80.10%
Invasive (Haemophilus influenza type b) 20,000 <50 >99.8%
Invasive (pneumococcal disease) 63,067 41,550 34.10%
Varicella 4,085,120 612,768 85

* Estimated annual average number of cases in the prevaccine era for each disease. Source: JAMA 2007;298:2155–63.
Source: MMWR 2011;60(32):1088–1101.

References

  1. https://www.cdc.gov/measles/cases-outbreaks.html
  2. https://www.cdc.gov/vaccines/vpd/mmr/public/index.html
  3. https://www.cdc.gov/measles/cases-outbreaks.html
  4. http://www.who.int/vaccine_safety/initiative/detection/immunization_misconceptions/en/index6.html