What is vaccination and why do we to vaccinate?
At some point, our ancestors began to recognize illness as a cause of death separate from dying of old age; when will probably never be known. However, as disease (literally “dis ease” or the absence of ease) was recognized, treatments also appeared. Most were ineffective and some seriously harmful.
The Hippocratic School (around 400BC) developed a concept of disease in which a balance between four “humours” (blood, yellow bile, black bile and phlegm) was essential to health. The physician's role was to help a patient balance their “humours." Of course, little in this concept stands up to scrutiny, although it could apply to folk whose “fast food” diets verge on toxicity.
At some point in the pre-Christian era, people began to realize that survivors of certain diseases could not get that disease again. The prime example is smallpox, a fearsome disease that killed 30 per cent of sufferers. People who recovered were immune to re-infection.
How vaccination began
In ancient China and India, attempts were made to administer small doses of smallpox to people hoping to give them a mild infection. Dried material was taken from smallpox scabs and finely ground. In China, this was blown into the nose. In India, the material was applied to scratched skin. Both methods generally caused mild infection, but resulted in lifelong immunity to smallpox.
That process, now called “variolation” after the variola virus responsible for smallpox, was brought to England by Lady Mary Wortley Montague, who became infected in Constantinople and survived, although her face was now disfigured. Determined to protect her children, she had her five-year-old son “engrafted” (as the procedure was called then) in 1718. Three years later, her daughter was also inoculated.
The variolation process itself was hazardous; some people developed smallpox and died. Moreover, handling powdered smallpox scabs was unsafe. A few decades ago, a Boston public library discovered an envelope in an old book. A letter inside advised the recipient, a Boston doctor, that three dry smallpox scabs were enclosed, which he could use to variolate his patients. These were in a tiny envelope. The librarian sent the scabs to the Centers for Disease Control (CDC) which confirmed they were indeed smallpox scabs – still viable and infective after two centuries.
Nearly 80 years after Lady Montague variolated her children, an English country doctor named Edward Jenner devised a safe method of immunizing people against this deadly disease. In the west of England where he practised medicine, Dr. Jenner learned that milkmaids were reputedly immune to smallpox.
In 1778, he tested this by variolating 15 women with cowpox scars. They had no reaction to the smallpox inoculation. He then gave a young lad material from a cowpox sore. The boy displayed cowpox symptoms (similar to but far less severe than smallpox). Several weeks later, he gave the lad material from a smallpox pustule, which was very risky. This time the lad showed absolutely no reaction.
Dr. Jenner carried on inoculating people with cowpox and rapidly became famous. His technique, from 1796, was called “vaccination” after the Latin word for cow, or “vacca”. The vaccination process remained unchanged for two centuries. In the 1970s, smallpox was deemed eradicated worldwide and most countries stopped vaccinating against smallpox by 1980.
We now have vaccines for a host of diseases. Examples include measles, mumps, chickenpox, polio, rubella, typhoid, yellow fever, tuberculosis, rabies, tetanus, whooping cough, influenza, hepatitis A and B, diphtheria, human papilloma virus, and others. A list of 14 vaccines are recommended for European and North American children, many combined into one injection.
Researchers are trying to improve the effectiveness of cholera and malaria vaccines, and to develop vaccines against ebola, zika and other diseases.
The most recent disease for which vaccines have been developed is, of course, COVID-19. Today’s challenge is to (a) acquire enough vaccine doses, and (b) improve distribution in developing countries such as most of Africa, South and Central America, and South East Asia.
Vaccines which must be kept cold cannot be administered to populations outside urban centres where electricity supplies are unreliable, making cold storage difficult or impossible. This is why the Janssen and Astra-Zeneca vaccines are being used in these countries.
How do vaccines work?
Imagine a medieval army with soldiers pressed into service from over a dozen dukes and earls. Also imagine that one commander gathered all the manpower under his command to a meeting before the battle.
At that meeting, he showed his troops the banners, armour and sword style, shield escutcheons and other identifying marks carried by the enemy. “Attack these men. Do not attack any soldiers whose banners, armour and escutcheons you see around you now!”
When it all begins, his side immediately recognizes the enemy, despite the battle’s excitement and dust. As a result, no soldiers on that side are killed by accident because they were misidentified.
Vaccination introduces a foreign substance into the body, a substance the body’s immune system begins to attack in various ways. Mounting this defense takes several days. The body must first recognize the foreign material – the job of the immune system. Then it manufactures antibodies to help attack the foreign agent.
At the same time, the body makes white blood cells some of which identify and mark the foreign substance. Once marked, other white blood cells ( “Killer T Cells”) destroy the foreign material and infected cells.
The latter is very important because infected cells are often co-opted into making more virus particles! We want to shut down these “factories."
Getting ill does this, too, but not as well. This is because vaccines are compounded with “adjuvant," a substance which enhances the immune response. Also, getting ill is usually far less comfortable for the victim, something vaccination tries to avoid. Of course, side effects may occur and can be serious, but generally far less so than getting the disease itself.
Vaccines are often delivered as two or more doses weeks apart. Remember, the body destroys the foreign material (vaccine) as rapidly as possible. A second or third dose reminds the body to continue building its defenses.
Producing vaccines
The very first vaccine against smallpox used cowpox virus. Closely related to smallpox, the latter caused mild infection in people. Unfortunately, few human diseases have close relatives whose agents can be used in this manner.
Researchers had to find a way to reduce the ability of the organism to cause disease, but keep its structure intact so the immune system could learn to recognize it.
Vaccination advanced when Louis Pasteur developed a method of “attenuating” disease organisms by drying, specifically the rabies virus (1885). Since rabies was 100 per cent fatal, rabid animals were common and there was no known treatment, Pasteur’s vaccination/treatment was welcome despite requiring over a dozen injections.
Other inactivation methods include careful heating or treatment with substances like formaldehyde. In 1923, there was a tetanus vaccine. In 1926, diphtheria was added. Whooping cough came in 1948, followed by the Salk’s famous polio vaccine in 1955.
Thanks to an easily administered oral version (Sabin’s polio vaccine), this crippling disease has nearly been eradicated worldwide except for parts of northern Nigeria and Pakistan where religious zealots claim vaccination against polio is a western plot to sterilize Muslims.
These days, vaccines are made by harmless bacteria with appropriate DNA spliced into their genetic code. They churn out antigens to trigger the immune response for specific diseases in quantity. This method has served us well for decades.
However, the latest method develops vaccines more rapidly than ever, and may also work to create drugs for certain diseases. Instead of persuading bacteria to do the job, scientists made messenger RNA (mRNA), which codes for a specific viral protein – much easier than making the protein. Packaged for injection, the person then makes the protein, triggering their immune system to develop defenses against it.
In closing, we have been vaccinating ourselves for a long list of diseases for at least five decades. This has gone a long way toward eliminating infectious diseases in our country. Combined with equipment to supply us with clean water and purifying our sewage, vaccination has added two decades of good health to our lives.
Also of note...
As a child, I occasionally attended chicken pox or measles “parties” hosted by parents of a child with the disease. Before there were vaccines against childhood diseases, parents recognized that all children should become infected to acquire lifelong immunity. This was valuable because children seldom developed severe symptoms. However, infection with one of these diseases could cause serious illness in an adult.
A friend caught mumps in his 40s. Often joked about because the sufferer could look like a chipmunk with seed-stuffed cheeks, my friend was off work for over a month. When he “recovered,” he was totally deaf in one ear.
COVID-19 is similar. It generally produces mild symptoms in children, but we now know it can saddle adults with severe, prolonged (perhaps permanent) symptoms.
Most of us will, eventually, acquire immunity to COVID-19. It is our choice whether this comes about through infection with the disease or by vaccination. We know vaccination creates better immunity, less discomfort and fewer side effects.
This makes vaccination the smart choice.
Peter Bursztyn is a self-proclaimed “recovering scientist” who has a passion for all things based in science and the environment. The now-retired former university academic has taught and carried out research at universities in Africa, Britain and Canada.
