With the emergence of new diseases and the resurgence of old ones, vaccines have become a popular topic of conversation. Whether in the news or at the modern water cooler — or Zoom session — people are talking about vaccine development like never before.
So, what is a vaccine? We all get them, often in childhood, but how do they really work? Simply stated, a vaccine stimulates a human immune response to a disease leading to immunization, or protection from that disease.
And, it is not an overstatement to say that vaccines have shaped the course of recent history.
1. Chickenpox
Chickenpox, which is the illness caused by the Varicella virus, used to be a hallmark of childhood. In fact, people would hold “chickenpox parties” simply to hasten exposure and control timing.
While the chickenpox illness often produced a fever and fatigue in patients, it was especially known for the itchy “pox” or blisters that formed all over the skin, and in the nose and mouth. Mostly a mild disease, it could become more serious for very young children, pregnant women, and adults, which was one of the reasons that parents’ liked to target contraction via parties and exposure in early childhood.
Once their little ones’ had the chickenpox mom and dad could check it off the list and treat their kiddos with rest and chicken soup. Plus, by controlling contraction they could prevent long absences from school and inconvenient outbreaks on family vacations. Naturally, with the introduction of the chickenpox vaccine in the mid-1990s, the frequency of outbreaks in the United States dropped sharply and the parties became a thing of the past.
Interestingly, the shingles illness is also caused by the Varicella virus but can only develop in a person who has had chickenpox. While technically it is still possible to develop shingles, which usually crops up later in life, after having the chickenpox vaccine as opposed to the illness – it is far less likely.
2. Smallpox, an Ancient Killer
By comparison, smallpox, another rash and blister-inducing illness, was anything but mild. Smallpox has a roughly 30% mortality rate, so it killed 30 out of every 100 people who came down with it. In addition to sores, the infected were also plagued with a variety of other symptoms including fever, fatigue, vomiting, sore throat, and severe headaches. And, if you didn’t die, you were likely left scarred, disfigured, or even blind.
Thankfully smallpox carries the distinction of being the only virus that’s been completely eradicated, as declared by the 33rd World Health Assembly.
On an interesting trivia note, the disease’s roots are ancient. Teams of virologists and archaeologists have actually found evidence of the smallpox virus in Egyptian mummies from more than 3,000 years ago. Thanks to modern vaccines, all those scientists were likely immune from smallpox when they made that discovery.
The smallpox vaccine, based on the 1796 research of Edward Jenner, an English Doctor with a keen eye for observation, was broadly accepted in the 1800s paving the way for the destruction of this nasty illness.
3. Diphtheria, Tetanus and Pertussis
With the success of the smallpox vaccine, it’s no wonder that vaccine development accelerated from there. By 1948 scientists and doctors had begun recommending childhood vaccinations, and embraced the practice of bundling certain vaccines to reduce the number of pricks that little ones had to endure.
Specifically, the vaccines for diphtheria, tetanus, and pertussis were combined into the single, and now familiar DTaP vaccine.
All three of these diseases are actually caused by bacteria as opposed to a virus, and to dramatic effect. While both diphtheria and pertussis start with cold-like symptoms, they soon grow far worse.
The diphtheria bacteria attack organs like the heart, kidneys, and liver, sometimes causing permanent damage or death. Pertussis, or whooping cough as it is more commonly known, escalates from cold-like symptoms to respiratory inflammation and severe cough.
Tetanus is perhaps most well-known for the symptom of lockjaw, but really the bacteria targets both the muscular and nervous systems and the disease has a 10-20% mortality rate in people who have not had the tetanus vaccine. So, don’t skip that DTaP vaccine.
The prevalence of all three of these diseases has been driven down by the DTaP vaccine, but they have by no means been eliminated. Naturally, they are more common in parts of the world where the practice of vaccination is less common, but notably, there have been pertussis outbreaks in the United States in recent years.
When combing through the history books you may find earlier reference to this vaccine as the DTP vaccine. It was modified to DTaP due to a change in the preparation of the pertussis portion of the vaccine. The “aP” portion of the DTaP abbreviation is short for “acellular pertussis.”
This evolution of the DTaP vaccine preparation and the vaccine bundle’s name is a powerful reminder that science never stands still.
4. Polio and Flu
Unfortunately, researchers can’t stand still because nature is constantly changing. Viruses mutate. Animals move between environments, meeting new and different animals for the first time. Life finds a way. And nowhere is this more evident than the seasonal flu.
The flu is actually caused by a handful of influenza viruses (A & B) for which influenza vaccines are modified seasonally based on trends and changes. After the extremely deadly flu pandemic of 1918 scientists worked tirelessly to isolate the influenza virus, leading to the development of the first flu vaccine in the 1940s.
However, due to the number of influenza virus variations and the small mutations in the influenza virus proteins, the 1950s and 1960s each delivered additional flu pandemics. Those pandemics spurred further scientific progress and the creation of public campaigns that encouraged U.S. citizens to get a seasonal flu shot. Campaigns that have largely been successful.
The other viral scourge of the 1950s was polio.
Polio is tricky. More than 70% of the time the virus has no impact, creates no symptoms in the person who has contracted polio. Other times the virus insidiously attacks the patient’s spinal cord leading to paralysis or even death. Dr. Jonas Salk, one of the scientists involved in the development of the flu vaccine in the 1940s also helmed the development of the polio vaccine. So confident was he in his vaccine that he actually took it himself and gave it to his family during the human testing phase.
Happily, there has not been a case of polio in the United States since 1979 and many global organizations are working to eradicate from the world entirely.
Today, the scientific community is adding another ingredient to their advances – speed. Vaccines are now being churned out faster than ever before in history. In fact, some labs are now developing vaccines based on projected future virus mutations. So, what will tomorrow bring? One thing is for certain — more change.
