Germ Theory and Vaccines

By Dr. Kelli Criss

As our country and the world continue to address the coronavirus outbreak, our blog, Germ Theory and Vaccines, looks back to the end of the nineteenth century.  This retrospective contextualizes our current search for a vaccine and efforts to “flatten the curve” of rising infectious cases.   

1875-1900: The Discovery of Germ Theory 

During the final quarter of the nineteenth century, a scientific methodology for comprehending and addressing epidemic diseases was created and thus, opened the field of modern bacteriology.  This period was characterized by the identification of the pathogens causing myriad illnesses like typhoid, cholera, tuberculosis, diphtheria, and tetanus.  The ability to make such ground-breaking discoveries was linked to advances in medical technology like aniline stains and microscopes with high magnification ability.  These stains, developed in the 1860s and 1870s, were dyes enabling bacteria cultures to be seen under a microscope.  Likewise, new microscopes enabled high magnification of bacteria without distortion in the images.   

With a greater understanding of the bacterial and viral sources of diseases, public-health methods to control the spread of illness launched.  Among these methods, were disinfecting the environments of people infected with disease and separating ill patients in sanatoriums.  Investigation of diseases worked hand-in-hand with bacteriology and vaccine discoveries to enable the prevention of disease.  Diphtheria is one such disease.  

Diphtheria: The First Widespread Disease Prevented by Vaccine 

Diphtheria was a challenge to diagnose, and therefore, study.  Having the same symptoms as other diseases, diphtheria was not easily diagnosed.  In 1884, the diphtheria bacillus was identified; however, another decade passed until any breakthrough in prevention occurred.  By the middle of the 1890s, a diphtheria vaccine was developed through the identification of the diphtheria antitoxin.  States like Illinois showed a major drop in the death rate from diphtheria with the advent of the vaccine.  To be exact, Illinois’s death rate fell from an 1886 rate of 113 people per 100,000 to a 1902 rate of 22 individuals per 100,000.  After such success, bacteria became the focus of the medical community and accelerated advances in public health. 

Our Guide into All Truth 

People are experiencing desperation and confusion globally as we face the current coronavirus pandemic.  We need God’s help greatly and grapple with maintaining our faith-centered focus.  Like us, the disciples struggled to reconcile the stress and bewilderment of the events Jesus foretold about his crucifixion with their need for Christ’s physical presence in their lives.  When Jesus was preparing the disciples for his crucifixion and resurrection, he promised them that he would send the Holy Spirit as a guide and comfort to them, saying  

“But when He, the Spirit of truth, comes, He will guide you into all the truth; for He will not speak on His own initiative, but whatever He hears, He will speak; and He will disclose to you what is to come.” John 16:13 (New American Standard) 

Throughout history, God’s Spirit has revealed truth to humans and been Immanuel, God with us.  We thank God for all the wisdom and understanding we have been given.  As the faith community, we pray for God’s truth to light our path concerning the coronavirus and we ask for wisdom for our leaders, healthcare providers, and researchers.   

For more information about Florida Faith and Freedom Coalition, check out our website or sign-up for our newsletter.   

Timeline of Events 

1862 – Louis Pasteur (1822-1895), French scientist, demonstrated airborne bacteria were the source of fermentation.  Due to these findings, scientists move away from believing disease is connected to environmental sources and embrace the notion of “germ theory.” 

1876- Robert Koch (1843-1910), a German scientist, while investigating anthrax in sheep and cattle, proves that particular pathogens or disease-causing agents like bacteria and viruses, cause disease.  

1882- Koch discovers the tuberculosis bacillus or bacteria. 

1879 – Louis Pasteur identifies how to use the bacilli or rod-shaped bacteria at the source of various illnesses in vaccinations.  The work of Edward Jenner (1749-1823), a British doctor, who discovered the smallpox vaccine, was instrumental in Pasteur’s innovation.   

1889 -1891 – 40 % of world’s population infected with influenza during epidemic. 


Hooper, J. (1999, February).  A New germ theory.  The Atlantic.  Retrieved from  

Tompkins, V. (1997).  American eras: Development of the Industrial United States, 1878-1899.  New York, NY: Gale 


Lecture 14: The Germ Theory of Disease from History 234: Epidemics in Western Society since 1600, an Open Yale Course

Leave a Reply

Your email address will not be published. Required fields are marked *