Vaccines are described as the single most effective medical intervention in history…more lives have been saved by vaccines than by any other treatment. In fact, vaccines have been so effective in preventing diseases that many people alive today do not realize how severe diseases like polio, measles, mumps, diphtheria, tetanus and pertussis can be.
I should confess that I am biased in favour of vaccinating – I was one of the first pharmacists to be certified to give vaccines in the province of New Brunswick and continued on to work with a team of nurses and pharmacists who taught and certified hundreds of pharmacists in several Canadian provinces. To do this, I studied large amounts of scientific information about many aspects of vaccines and their use.
Vaccines are overwhelmingly safe…most reactions are minor, such as a sore arm or mild fever. All reactions are carefully tracked and documented to detect any potential problems as soon as possible. Severe anaphylactic (allergic) reactions occur less than 2 times per million doses given, but every person administering vaccines is trained to detect and treat these severe reactions and must be equipped with medications needed to do so.
Concerns have been expressed about the possibility that giving several vaccines at once could overwhelm the immune system, but scientists confirm our immune systems have the capacity to handle several thousand vaccines at once. They point out that during a normal day, a child is exposed to several hundred different antigens that trigger the immune system into action, and this is what a vaccine does.
An article in 1998 suggested that the measles vaccine was causing autism, but this has been disproven long ago. In spite of this, some parents still refuse to vaccinate their children based on this and other misinformation.
The mercury-containing preservative, thimerosol, has also been of concern to some parents. Although it was never demonstrated to cause a mercury-related health problem, it has been removed from all child vaccines manufactured since 2001, except flu vaccine that comes in multi-dose vials, most likely due to the number of allergies to this ingredient. Note that single-dose influenza vaccine does not contain this ingredient.
Another common vaccine ingredient that has drawn concern from parents is formaldehyde, used to inactivate viruses and bacterial toxins in vaccine manufacturing. Although most is removed from the final product, a very small amount remains. The human body actually produces its own formaldehyde when proteins are processed, and a baby’s body at any given time will contain 10 times the amount that would be in a vaccine. This small amount has been shown to be completely safe and our bodies have mechanisms to eliminate it, along with the formaldehyde we regularly produce ourselves. Far more dangerous amounts are found in second-hand cigarette smoke and car exhaust, and most dangerous are the workplace exposures to formaldehyde, such as hairdressers exposed to some hair smoothing products that produce formaldehyde when used.
Although we rarely see many of the childhood diseases we vaccinate against now, they still exist and could quickly become commonplace again. We saw this with pertussis (whooping cough) in our province. Because of higher rates of reactions from a vaccine that contained whole inactivated viruses, immunization rates dropped and over a thousand cases were documented in one season. Pertussis is similar to a mild cold in a healthy adult, but can be fatal to a small baby. Government’s response was to inform the public and step up vaccine availability to bring the disease under control again. There is ongoing research to ensure that the resurgence is not due to decreased effectiveness of a newer improved vaccine with fewer reactions.
It is true that some vaccines are more effective than others. The shingles vaccine, for example, only reduces occurrence of the disease by about 50%, although it is pointed out that cases tend to be less severe in those who have been vaccinated, and “post herpetic neuralgia”, pain that can continue for weeks or months after a bout of shingles, was also reduced. Many feel that even this level of resistance to getting shingles makes it worthwhile taking the injection.
It’s flu season now, so let’s talk about the flu vaccine… The severity of influenza will vary from year to year, depending on the nature of the strains going around that particular year. Because the flu virus changes frequently, researchers track influenza cases around the world and choose 3 to 4 strains that they expect could cause the worst illness, creating a new combination each year.
The flu is not just a bad cold…it kills 300,000 to 500,000 people in an average year around the world, mostly the elderly. Young children are also at increased risk, as are pregnant women, and those already in poor health or with chronic conditions like asthma or heart disease. Vaccinating a pregnant woman also gives protection to her baby, a definite plus since the vaccine cannot be given to children under 6 months of age.
Some don’t bother getting the vaccine, stating they are healthy and not worried about catching the flu, but we all need to keep in mind that we could pass the illness on to someone who is more vulnerable than we are. If more people are vaccinated, it is less likely we will have a large epidemic – this is referred to as “herd immunity”…the whole community is protected because there are fewer people who can spread the virus to others.
I have had clients claim that they “caught the flu” from the flu vaccine, but this is not possible. The pieces of virus in the vaccine are dead and cannot start to grow causing an infection…it's just not possible. It is possible, however, to catch the flu from someone else in the first 2 weeks after a flu shot because it takes 2 weeks for antibodies that protect us from the virus to develop in our bodies.
However, I did read about one incorrectly made batch of vaccine that reached the market in the ‘90s that actually did cause some severe illness. The manufacturing problems were detected and corrected to avoid recurrence of a similar problem. The manufacturing of vaccines is highly regulated to ensure "bad batches" do not occur today.
Vaccines containing an “adjuvant”, an extra ingredient designed to increase response to the vaccine in those with weaker immune systems, are also known to have somewhat increased reactions such as pain in the area of the injection and mild fever. The special vaccine produced to fight the H1N1 flu epidemic of 2009 contained an adjuvant to ensure the highest level of immunity possible would be produced. This H1N1 virus was similar to the one that caused the Spanish Flu of 1918. That epidemic killed 50 to 100 million people, about 3 to 5% of the world’s population at that time, many of them young healthy adults.
Again this year, experts are predicting a flu season that could be more severe than others. Getting a flu shot is free for many, and takes just a few minutes. And it’s available as close as your neighbourhood pharmacy or doctor’s office. So why not take a few minutes and protect yourself and others around you from a preventable illness!
If you have any questions about vaccines that I haven't answered, click the "Comments or Questions" button, or ask your pharmacist or doctor!
