What If Vaccines Were Never Invented?

The Actual History

The story of vaccination begins in earnest with Edward Jenner's groundbreaking work in the late 18th century, though the concept has earlier roots. For centuries, smallpox had been one of humanity's greatest scourges, killing approximately 30% of those infected and leaving survivors scarred or blind. In some epidemics, the mortality rate reached 60%, and the disease was responsible for an estimated 300-500 million deaths during the 20th century alone.

Early forms of immunization existed before Jenner. In Asia and the Middle East, a practice called variolation had been used for centuries, which involved deliberately infecting people with material from smallpox pustules, typically causing a milder form of the disease and subsequent immunity. Lady Mary Wortley Montagu famously introduced this practice to England in the early 18th century after observing it in Constantinople.

However, the pivotal moment in vaccination history came in 1796 when Edward Jenner, an English physician, performed his famous experiment. Jenner had observed that milkmaids who contracted cowpox, a related but milder disease, seemed protected from smallpox. On May 14, 1796, Jenner took material from a cowpox sore on milkmaid Sarah Nelmes and inoculated eight-year-old James Phipps. Six weeks later, Jenner exposed Phipps to smallpox material, but the boy did not develop the disease, demonstrating immunity.

Jenner published his findings in 1798 in "An Inquiry into the Causes and Effects of the Variolae Vaccinae," coining the term "vaccine" from the Latin word for cow (vacca). Despite initial skepticism, vaccination gradually gained acceptance and spread throughout Europe and the Americas in the early 19th century.

The next major breakthrough came with Louis Pasteur in the late 19th century. Building on Jenner's concept, Pasteur developed vaccines for chicken cholera (1879), anthrax (1881), and rabies (1885). Pasteur's work expanded the principle of vaccination beyond just smallpox and established the scientific basis for attenuated vaccines.

The 20th century saw an explosion of vaccine development:

1920s-1930s: Diphtheria, tetanus, pertussis, and tuberculosis vaccines
1950s: Jonas Salk's inactivated polio vaccine (1955) followed by Albert Sabin's oral polio vaccine (1961)
1960s: Measles (1963), mumps (1967), and rubella (1969) vaccines, later combined into the MMR vaccine
1980s: Hepatitis B, Haemophilus influenzae type b (Hib) vaccines
1990s-2000s: Hepatitis A, chickenpox, pneumococcal, and rotavirus vaccines

This progress culminated in one of medicine's greatest triumphs: the global eradication of smallpox, officially declared by the World Health Organization in 1980. This marked the first time humanity had completely eliminated a major infectious disease through deliberate intervention.

Vaccination programs have dramatically reduced the incidence of many deadly diseases. Polio has been eliminated from most countries (with wild poliovirus remaining endemic in just two countries as of 2023). Measles deaths globally decreased by 73% between 2000 and 2018. Overall, vaccination prevents an estimated 2-3 million deaths annually worldwide, according to the WHO.

Modern vaccination schedules in developed countries routinely protect against more than a dozen diseases, and new technologies like mRNA vaccines (demonstrated dramatically with COVID-19 vaccines) have opened new frontiers in vaccine development. The COVID-19 pandemic showcased both the importance of vaccines and the remarkable speed at which they can now be developed, with effective vaccines deployed within a year of the emergence of a novel pathogen.

The Point of Divergence

What if vaccines were never invented? In this alternate timeline, we explore a scenario where the concept of vaccination never emerged as a medical practice, leaving humanity vulnerable to infectious diseases that have been largely conquered in our timeline.

The most plausible point of divergence would be the absence of Edward Jenner's crucial observation and experiment in 1796. There are several ways this divergence might have occurred:

Jenner's Early Death: Edward Jenner might have died before his breakthrough, perhaps from one of the many diseases that claimed lives in the 18th century. Born in 1749, Jenner could have succumbed to typhoid, tuberculosis, or even smallpox itself before conducting his famous experiment.
Failed Initial Experiment: Jenner's experiment with James Phipps might have failed to demonstrate immunity. Perhaps the cowpox strain used wasn't effective, or Phipps had some natural resistance to smallpox unrelated to the cowpox exposure.
Suppression of Findings: The medical establishment of the time might have more effectively discredited Jenner's work. His ideas initially faced significant skepticism and ridicule. In this alternate timeline, perhaps influential medical authorities successfully branded his method as dangerous quackery, preventing its adoption.
Missing the Cowpox Connection: The folk wisdom about milkmaids' resistance to smallpox might never have been noticed or taken seriously by anyone with the scientific background to investigate it. Without this crucial observation, the cowpox-smallpox connection might have remained undiscovered.
Religious or Cultural Objections: More intense religious objections to the practice of introducing animal material into humans could have prevented the acceptance of vaccination. If religious authorities had universally condemned the practice as unnatural or unholy, it might never have gained traction.

Most likely, the divergence would combine several of these factors. Imagine a timeline where Jenner either never made his observation about milkmaids or where his initial experiments appeared to fail. Without this crucial first step, the scientific principle of vaccination might have remained undiscovered for many decades, or possibly even longer.

Without Jenner's pioneering work establishing the principle of vaccination, later scientists like Louis Pasteur would have lacked the foundational concept upon which to build. The germ theory of disease might still have developed, but the specific technique of using attenuated or inactivated pathogens to confer immunity would be missing from medicine's toolkit.

This absence would create a dramatically different world, where humanity remained at the mercy of infectious diseases that, in our timeline, have been largely controlled or even eradicated through vaccination programs.

Immediate Aftermath

Persistent Smallpox Epidemics

The most immediate and noticeable consequence would be the continued devastation wrought by smallpox through the 19th century and beyond:

Continued High Mortality: Without vaccination, smallpox would have continued to kill approximately 400,000 Europeans annually, as it did in the 18th century. Globally, the death toll would have remained in the millions each year.
Unchanged Demographics: The demographic transition that occurred in Europe and North America during the 19th century would have been significantly altered. Population growth would have been slower due to the continued high child mortality from infectious diseases.
Persistent Variolation: The practice of variolation (deliberate infection with smallpox material) would have continued as the only method of attempting to control smallpox, despite its significant risks. This would have maintained a steady background level of smallpox cases and deaths even when not in epidemic phases.
Different Beauty Standards: The ubiquity of smallpox scarring would have maintained different beauty standards. The unmarked face would have remained rare enough to be remarkable, and cosmetic products to hide pockmarks would have continued as a major industry.

Impact on Medical Development

Without vaccination as a successful model of preventive medicine:

Delayed Germ Theory: While Pasteur and Koch might still have developed the germ theory of disease in the mid-to-late 19th century, the lack of a proven method to induce immunity would have significantly hampered its practical applications.
Alternative Focus: Medical research might have focused more intensively on therapeutic rather than preventive approaches. The development of antibiotics might have occurred earlier as the medical establishment desperately sought ways to treat, rather than prevent, infectious diseases.
Public Health Measures: Without vaccination, other public health measures would have taken greater precedence. Quarantine, sanitation, and clean water initiatives might have received even more emphasis than they did in our timeline.
Different Institutional Development: Without the success of vaccination programs, public health institutions would have developed differently. The model of mass preventive medical interventions might never have emerged in the same way.

Political and Social Consequences

The continued threat of epidemics would have shaped society in profound ways:

Urban Development: Cities might have developed differently, with more emphasis on ventilation and preventing overcrowding to limit disease spread. The dense urban centers that emerged during the Industrial Revolution might have been considered too dangerous without some protection against epidemics.
Colonial Expansion: European colonization efforts would have faced even greater challenges. In our timeline, indigenous populations were devastated by diseases brought by colonizers, while Europeans eventually gained protection through vaccination. Without this advantage, colonial powers might have found expansion more difficult and costly.
Different War Outcomes: Military campaigns throughout the 19th century would have been significantly affected by epidemic disease. Napoleon's campaigns, the American Civil War, and colonial conflicts would have seen even higher proportions of deaths from disease rather than combat.
Travel Restrictions: International quarantine measures would have remained stringent and widespread. The ease of global travel that developed in the late 19th and early 20th centuries might have been significantly constrained by fears of disease spread.
Class Divisions: The ability to isolate oneself from disease through private living arrangements, access to clean water, and the ability to flee epidemic areas would have further reinforced class divisions, with the wealthy having significantly better survival prospects.

Early 20th Century Context

By the dawn of the 20th century, the world would have looked markedly different:

Population Distribution: The global population would have been significantly lower, with different distribution patterns reflecting the uneven impact of diseases across regions and climates.
Medical Practice: Without the model of vaccination, medical practice would have evolved along different lines. The concept of preventive medicine might have been significantly underdeveloped compared to our timeline.
Public Expectations: People would have continued to expect and fear epidemic disease as an inevitable part of life. The psychological impact of living with this constant threat would have shaped culture, literature, and social practices in profound ways.
Different Scientific Heroes: The pantheon of medical heroes would not include Jenner, Pasteur (for his vaccine work), Salk, or Sabin. Different scientists, perhaps those who developed early antibiotics or other therapeutic approaches, would have been celebrated instead.

The world entering the 20th century would thus be one still firmly in the grip of infectious disease, with smallpox, diphtheria, tetanus, and other vaccine-preventable diseases continuing to claim millions of lives annually. The stage would be set for even greater catastrophes as urbanization and global connectivity increased without the protection that vaccination provides.

Long-term Impact

Global Demographic Patterns

Without vaccines, population dynamics throughout the 20th century and into the 21st would have followed a dramatically different trajectory:

Lower Global Population: The world's population would likely be billions fewer than our current 8 billion. High childhood mortality from vaccine-preventable diseases like measles, polio, diphtheria, and pertussis would have persistently suppressed population growth, particularly in developing regions.
Different Age Pyramids: Population age structures would show much narrower bases, with fewer children surviving to adulthood. The elderly would represent a smaller percentage of the population due to both lower life expectancy and smaller birth cohorts reaching old age.
Altered Migration Patterns: Disease patterns would have influenced human migration differently. Regions with naturally lower disease burdens might have become more densely populated, while tropical areas with higher disease prevalence might have remained less developed.
Slower Urbanization: The massive urbanization of the 20th century might have been tempered by the persistent threat of epidemic disease in crowded environments. Cities might have developed with lower population densities and different architectural patterns to mitigate disease spread.

Public Health and Medical Development

The medical field would have evolved along a dramatically different path:

Treatment-Focused Medicine: Without the preventive model established by vaccination, medicine would have remained primarily treatment-focused. Resources that in our timeline went to developing vaccines would have been channeled into therapeutic approaches.
Advanced Antibiotics and Antivirals: Research into antibiotics and antiviral medications would likely have progressed more rapidly and received greater investment, as they would represent the primary defense against infectious disease.
Public Health Infrastructure: Quarantine facilities, fever hospitals, and sanitation systems would have remained central to public health strategies. Cities would maintain substantial infrastructure for isolating the sick during inevitable epidemics.
Different Healthcare Systems: The model of universal healthcare might have developed differently, perhaps focused more on epidemic response than preventive care. Resources would be disproportionately allocated to infectious disease control rather than chronic disease management.
Advanced Diagnostics: Early and rapid diagnosis would be crucial in a world where treatment rather than prevention was the primary approach. Diagnostic technologies might have advanced more quickly than in our timeline.

Major Historical Events Reshaped

The absence of vaccines would have profoundly altered major historical events of the 20th century:

World Wars and Military Conflicts

Different World War I Dynamics: The Spanish Flu pandemic of 1918-1919, which killed an estimated 50 million people globally, would have been just one of many major pandemics. Military operations during WWI would have been even more severely affected by disease outbreaks.
Altered World War II Outcomes: Military campaigns would have been hampered by disease outbreaks among troops and civilian populations. The massive mobilization of forces would have spread epidemics across continents, potentially changing the course and duration of the war.
Cold War Biological Focus: The biological weapons race might have overshadowed the nuclear arms race, with superpowers investing heavily in developing and defending against weaponized pathogens in a world already accustomed to deadly epidemics.

Economic Development

Disrupted Industrial Progress: Regular epidemics would have caused frequent disruptions to industrial production and economic development. The economic boom periods of the 20th century would have been repeatedly interrupted by disease-related workforce reductions and social disruptions.
Different Corporate Landscape: The pharmaceutical industry would have developed differently, focusing on treatments rather than preventives. Companies specializing in sanitation, air purification, and personal protection equipment would be economic giants.
Altered Globalization: The intensification of global trade and travel that characterized the late 20th century would have proceeded more cautiously and with more barriers. International quarantine protocols would remain a significant aspect of international relations.

Social and Cultural Impact

Persistent Disease Consciousness: Disease awareness would remain at the forefront of public consciousness. Architecture, urban planning, social customs, and even fashion would reflect the ongoing need to mitigate disease transmission.
Different Educational Patterns: School systems would have adapted to frequent closures during epidemics. Remote or distributed education models might have developed earlier out of necessity rather than technological opportunity.
Cultural Expressions: Art, literature, and popular culture would contain much more prominent themes of disease, mortality, and transience. The cultural optimism of the late 20th century might have been tempered by the persistent threat of epidemic disease.

The Modern Era (2000-2025)

By the 2020s, the world would look radically different from our current reality:

Endemic Disease Landscape: Diseases eliminated or nearly eliminated in our timeline—smallpox, polio, diphtheria, measles—would remain endemic globally, with periodic devastating epidemics.
COVID-19 Magnified: The COVID-19 pandemic would have been even more catastrophic in a world without pre-existing vaccine technologies and infrastructure. The rapid development of mRNA vaccines would not have been possible without the century of vaccine science preceding it.
Different Digital World: Digital connectivity might have accelerated even faster as a means of maintaining economic and social activity during frequent disease outbreaks. Remote work, virtual entertainment, and digital commerce might have become dominant earlier out of necessity.
Medical Apartheid: Disparities in disease burden would likely be even more pronounced between wealthy and poor regions. Advanced treatment options would be available to the wealthy, while preventable diseases would continue to devastate poorer communities.
Different Environmental Priorities: With lower population pressures but more emphasis on spaces that minimize disease transmission, environmental challenges and priorities would differ significantly from our timeline. Urban sprawl might be greater as people sought less dense living arrangements.
Specialized Architecture: Buildings would incorporate advanced ventilation systems, antimicrobial surfaces, and designs that minimize disease transmission as standard features. Public spaces would be designed to allow rapid conversion to medical use during epidemics.
Altered Geopolitical Power Balance: Nations with naturally lower disease burdens or better natural isolation (island nations, countries with low population densities, or colder climates less hospitable to many pathogens) might have emerged as dominant powers, reshaping the geopolitical landscape.

By 2025, humanity would have developed sophisticated coping mechanisms for living with infectious disease, but the fundamental vulnerability created by the absence of vaccination would have shaped a world profoundly different from our own—one with lower population, different power structures, altered economic patterns, and a persistent consciousness of epidemic threat as a fundamental fact of human existence.

Expert Opinions

Dr. James Montgomery, Professor of Medical History at Oxford University, offers this perspective: "The absence of vaccination from medical practice would represent the single most significant alteration to public health imaginable. We tend to forget that the predictable life course we now take for granted—where most children survive to adulthood and most adults reach old age—is a very recent development, made possible largely through vaccination. Without Jenner's breakthrough, we might have eventually developed antibiotics and other treatments, but the preventive paradigm in medicine would be fundamentally weaker. The demographic, economic, and social consequences would be profound, essentially creating a world still living with the epidemiological conditions of the pre-modern era, albeit with more sophisticated treatments available for those who fell ill."

Dr. Elena Vasquez, Epidemiologist and Public Health Historian at the CDC, explains: "In a world without vaccines, we would likely see cycles of adaptation—both biological and social. Humans would have evolved some additional resistance to common pathogens through natural selection, though at tremendous cost in suffering and death. Socially, we would have developed elaborate systems for minimizing transmission: different architectural styles, different social customs, and probably much more distributed patterns of living and working. The centralized, dense urban environments that define our modern world might seem recklessly dangerous in such a timeline. I suspect technology would have been directed much more intensively toward disease avoidance and treatment, perhaps giving us more advanced filtration systems, pathogen detection capabilities, and therapeutic approaches than we currently possess. But these would be poor substitutes for the protective power of vaccines."

Professor Takashi Yamamoto, Comparative Demographer at Tokyo University, comments: "The demographic implications of a vaccine-free world are staggering. Without vaccination, the demographic transition that underpins modern society would have been significantly delayed and altered. High childhood mortality would have persisted much longer, maintaining high fertility rates but lower population growth. The aging societies we now see in developed nations would not exist in the same form. Instead, we would likely see a much smaller global population with very different distribution patterns, concentrated in areas naturally less susceptible to infectious disease spread. The socioeconomic consequences of these altered demographics would touch every aspect of human society, from family structures to economic systems to geopolitical power dynamics. It's not just that populations would be smaller—they would be fundamentally different in composition and distribution, creating an almost unrecognizable global human landscape."