Vaccines: From Smallpox to COVID-19

The Evolution of the Vaccine

The word “vaccine” has been on the tip of everyone’s tongues lately, and for good reason. Historically, vaccines have been used to prevent the spread of – and sometimes even eradicate – infectious diseases. Thanks to medical immunization, naturally occurring smallpox has been eliminated, and polio has been virtually erased. But how did we reach that point, and where are we going from here? Stay tuned to learn more about vaccines and how the stage is set for them to change the course of the COVID-19 pandemic. 


By Anna Hill


Dr. Paul Cornea headshot
Dr. Paul Cornea
Infectious Disease Specialist,
CHI Memorial Infectious Disease Associates

Infectious diseases have plagued civilization for millennia. The first recorded pandemic in history was the Plague of Athens, which killed about 100,000 people in 430 BCE. Perhaps the most infamous pandemic, The Black Death, was a form of bubonic plague that emerged in the 1340s and would recur every few decades up through the 18th century, ultimately killing around 50 million. In the last century, the Spanish Flu wreaked havoc in 1918 and resurged in the ‘50s and ‘60s, also taking the lives of 50 million. However, over the last 200 years, medicine has made incredible strides regarding infectious diseases – not only in treatment, but in prevention.

As the years have gone by, successful vaccines for diseases like smallpox, typhus, cholera, polio, tuberculosis, and the flu have been developed, which has greatly reduced or virtually eliminated the possibility of a widespread epidemic caused by known strains of those diseases. This kind of success is what currently gives everyone hope for the newly developed COVID-19 vaccines, as they will be a giant step forward when it comes to returning to life as we once knew it. 


Dr. Eugene Ryan headshot
Dr. Eugene Ryan
Internal Medicine Physician,
Parkridge Medical Group

Early Vaccines

Though vaccines have only existed in their currently known form since the end of the 18th century, the idea of inoculation – deliberate introduction of viral material to the body to prevent greater infection – has been hinted at since 10th-century China. The practice transferred particles from an infected person to the uninfected person via inhalation or incision. 

In the West, Edward Jenner is generally considered the founder of vaccines, as he performed successful inoculation of smallpox in 1796, with the first official smallpox vaccine being developed just two years later. French biologist Louis Pasteur is to thank for the development of the cholera and anthrax vaccines, which he developed nearly a century after Jenner’s smallpox immunity experiment. Beyond the turn of the 20th century, vaccine development and success increased exponentially.

illustration of a Doctor giving a woman a vaccine

Dr. Jay Sizemore headshot
Dr. Jay Sizemore
CMO, Cempa Community Care
Medical Director of Infection Prevention, Erlanger Health System

Modern Vaccines

In the last 100 years, a wide variety of vaccines has been developed and implemented across the globe. In the 1950s, one of the most vital vaccines that the general public awaited was the polio vaccine, as polio, a life-threatening disease that can leave one paralyzed, had begun to sweep through children in epidemics every summer. In 1955, virologist Jonas Salk’s polio vaccine was deemed effective, and distribution began shortly after. Thanks to his vaccine and its further advancements, polio has been considered eliminated from the United States for over 30 years. 

As the 20th century progressed, so did vaccine research. After the success of the polio vaccine, vaccines for the measles, mumps, and rubella followed in the next decade. In the 1970s, use of the smallpox vaccine was discontinued, as the disease had been eradicated. Hepatitis and meningitis vaccines came next, as did the discontinuation of the polio vaccine in the year 2000 thanks to elimination of the disease. Most recently, successful vaccines for HPV and different variations of the flu have been developed, and medical researchers are constantly working to produce new vaccines for diseases that persistently pervade society.


How Vaccines Work

Vaccines introduce a very weak or inactivated version of the virus to the body in a carefully measured dose. It then reproduces in the body a very limited amount of times – just enough for the body to begin producing “memory B cells,” which will protect against infection for that particular virus in the future. The COVID-19 vaccines, however, are a new type of vaccine called an mRNA vaccine, which teaches the body’s cells to make a protein that triggers the immune response needed to protect the body from infection.


The Impact of Vaccines 

The development and advancement of vaccines has had an undeniably positive impact on public health. Dr. Paul Cornea, an infectious disease specialist with CHI Memorial Infectious Disease Associates, emphasizes the importance of vaccines, especially in regard to children’s health. “The vaccines have had a tremendous role in reducing mortality, especially in children, to the point that the younger generations are completely unaware of the devastating effects of the infections prevented by vaccines,” he says. 

As previously mentioned, vaccines can also play a role in eliminating a public health crisis if they are used on a consistent and widespread basis. Dr. Jay Sizemore, chief medical officer at Cempa Community Care and the medical director of infection prevention at Erlanger Health System, cites the measles vaccine as an example of how vital they are to public health: “The World Health Organization (WHO) granted the United States a Measles Elimination Status in 2000. Our country nearly lost that status in 2019 when 1,282 cases were reported, largely in individuals who had forgone this vaccine.” 

illustration of doctors looking at scan of lungs

The COVID-19 Vaccine

In March of 2020, the WHO officially declared COVID-19 to be a global pandemic. A mere nine months later, the first vaccine for the virus, created by Pfizer, was given the green light by the U.S. Food and Drug Administration, with the Moderna vaccine following shortly after. Dr. Eugene Ryan, an internal medicine physician with Parkridge Medical Group, considers these vaccines, proven to be over 90% effective, game changers when it comes to infectious diseases. “The most formative vaccine in recent history will have to be the COVID-19 vaccine,” he explains. “This vaccine was developed in record time to battle a global pandemic.” 

As these vaccines begin to roll out in phases to the public, medical professionals are optimistic. When asked about the outlook for 2021, Dr. Sizemore believes it to be “excellent,” saying, “I suspect that we will be able to offer a COVID-19 vaccine to all who want it in our country during the first six months of 2021.” Dr. Cornea believes the year will be an excellent opportunity for a global learning experience, stating, “I also hope that the vaccines will continue to prove their safety and the people who are reluctant to take the vaccine now will later come on board.” 

While the current state of the global pandemic might feel disheartening, Dr. Ryan believes there is much hope to be had. “My hope is that we will vaccinate over 90% of the population in the next 12 months,” he says. “The outlook is dim right now, like one candle in the darkness – but this darkness is brightening with everyone who gets immunized, and soon the darkness will be gone.” HS

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