Acad. Eduardo Antonio Lara-Pérez,1 Acad. Ulises Reyes Gómez2
Abstract
Vaccination is one of the most significant achievements in public health, fundamentally transforming the fight against infectious diseases. It began with Edward Jenner’s pioneering work on smallpox, which led to the disease’s global eradication in 1980. More recently, the rapid development of mRNA vaccines against SARS-CoV-2 has demonstrated their effectiveness in preventing, controlling, and eradicating pathogens. Despite these successes, the resurgence of preventable diseases like measles and polio highlights the vulnerability of herd immunity and the real impact of anti-vaccine movements. Moreover, climate change adds a new layer of complexity by altering the geographical distribution of vectors such as mosquitoes, which increases the risk of diseases like chikungunya and malaria.
This manuscript explores the historical evolution of immunization, analyzes recent vaccine technologies, and discusses the interconnected challenges of disease resurgence, public skepticism, and the effects of climate change. It underscores the need for continuous surveillance and a proactive global health strategy.
Keywords: vaccination, immunization, COVID-19, re-emerging diseases, climate change, public health, smallpox, chikungunya, malaria, herd immunity
Resumen
La vacunación representa uno de los logros más significativos en Salud Pública, transformando fundamentalmente la lucha contra las enfermedades infecciosas. Desde la innovación pionera de Edward Jenner contra la viruela, que culminó con su erradicación mundial en 1980, hasta el desarrollo acelerado de vacunas de ARNm contra el SARS-CoV-2, las vacunas han demostrado su capacidad para prevenir, controlar y erradicar patógenos. A pesar de estos éxitos, el resurgimiento de enfermedades prevenibles, como el sarampión y la polio, pone de relieve la fragilidad de la inmunidad de grupo y el impacto de los movimientos antivacunas. Además, el cambio climático introduce una nueva capa de complejidad al alterar la distribución geográfica de vectores como los mosquitos, lo que favorece la aparición de enfermedades como el Chikunguña y el paludismo.
Este manuscrito explora la evolución histórica de la inmunización, analiza las tecnologías de vacunas recientes y analiza los desafíos interconectados del resurgimiento de enfermedades, el escepticismo público y el impacto del cambio climático, subrayando la necesidad de una vigilancia continua y una estrategia de salud global proactiva.
Palabras clave: vacunación, inmunización, COVID-19, enfermedades reemergentes, cambio climático, salud pública, viruela, Chikunguña, paludismo, inmunidad de grupo
Introduction
The battle against infectious diseases has been an integral part of human history. Edward Jenner discovered that exposure to the cowpox virus conferred protection against the deadly smallpox virus, which claimed millions of lives each year. This groundbreaking observation laid the foundation for modern immunology over 200 years ago. In his seminal 1798 work, “An Inquiry into the Causes and Effects of the Variolae Vaccinae,” he documented his findings, heralding the dawn of the vaccine era.1 A significant achievement in this ongoing struggle occurred in 1980 when smallpox was declared eradicated worldwide, a result of the World Health Organization’s effective mass vaccination campaigns. This moment marked a remarkable milestone in the field of medicine.2
In the 20th century, the introduction of vaccines for diseases such as pertussis, polio, diphtheria, tetanus, and measles led to a remarkable increase in life expectancy and saved countless lives.3 However, declining vaccination rates have resulted in the resurgence of preventable diseases, largely due to complacency about the decrease in illness and the widespread dissemination of misinformation. This resurgence highlights the critical need for timely responses, a necessity that was starkly illustrated by the COVID-19 pandemic, which showcased the rapid development and deployment of innovative technologies like viral vector and mRNA vaccines at an unprecedented speed.4
Development of Immunization: From Empiricism to Biotechnology
The Idea of Immunity and the Legacy of Smallpox
Jenner’s research highlighted the concept of protective immunity developed through exposure to a similar but less harmful agent.1 This foundational work laid the groundwork for the creation of inactivated vaccines, such as the injectable polio vaccine (IPV), and attenuated vaccines, including those for measles, oral polio (OPV), and tuberculosis (BCG).5 As a result, Five Health has significantly benefited from the universal immunization campaigns made possible by these advancements in vaccine technology.
Use of mRNA technology and COVID-19 to address emerging threats
The COVID-19 pandemic led to an extraordinary acceleration in vaccine development, significantly advancing medical science. Messenger RNA (mRNA) vaccines, such as those created by Moderna and Pfizer-BioNTech, mark a groundbreaking technological achievement.6 Unlike traditional vaccines that introduce a component of the virus, mRNA vaccines instruct the body’s cells to produce the SARS-CoV-2 spike protein, thereby initiating a robust immune response. The successful deployment of these vaccines underscores the potential of mRNA technology for effectively addressing future pandemics.
Developing Vaccines for Emerging and Recurrent Diseases Presents Difficulties
The Impact of Climate Change on Malaria and Chikungunya
Aedes aegypti and Aedes albopictus mosquitoes are the primary vectors of chikungunya fever, a disease that has recently emerged in non-endemic regions due to the geographical expansion of outbreaks. Developing an effective vaccine for chikungunya presents challenges, primarily because it must offer protection against multiple virus genotypes.7 Likewise, malaria, caused by the Plasmodium parasite, continues to be a significant global contributor to childhood morbidity and mortality.8 Climate change plays a crucial role in this context, as rising temperatures and altered rainfall patterns are expanding mosquito habitats, thereby facilitating the spread of infectious diseases to new populations.9
The Respiratory Syncytial Virus (RSV) Vaccine
Respiratory Syncytial Virus (RSV) is one of the primary causes of respiratory infections in both older adults and newborns. Recently, the first RSV vaccines have received approval, marking a significant advancement in safeguarding these vulnerable populations. The vaccines represent a crucial step in protecting at-risk individuals. The virus’s F protein serves as the target for the immune response; its instability has contributed to the lengthy and intricate process of developing these vaccines.10
The Resurgence of Preventable Diseases and the Value of Herd Immunity
The resurgence of preventable diseases underscores the critical importance of herd immunity. While vaccinations have significantly reduced the incidence of many diseases, some that were once nearly eradicated are making a comeback, largely due to insufficient immunization rates. A measles outbreak, for instance, has recently reemerged in Europe and the Americas, driven by a lack of awareness and declining vaccination coverage.11 Herd immunity, which protects those who cannot be vaccinated, relies on a substantial portion of the population being immunized. When this percentage drops, the cycle of transmission can restart, endangering the most vulnerable individuals, including young children, people with compromised immune systems, and the elderly.12
Discussion
Vaccination has proven to be the most effective disease prevention strategy in the history of medicine, providing benefits that should not be taken for granted. The COVID-19 pandemic, along with the resurgence of diseases like polio and measles, has underscored the critical need for research funding, epidemiological surveillance, and public education.
Moreover, the One Health concept, which emphasizes the interconnectedness of human, environmental, and animal health, is becoming increasingly relevant. The health of animals is not only crucial for ecosystem balance but also significantly impacts disease dynamics. Climate change exacerbates these challenges by altering ecological niches and facilitating virus transmission.9
To address these issues, a comprehensive approach is essential—one that integrates vaccine development with strategies for climate change mitigation and adaptation. This strategy should include advancing new platforms for neglected infections and making substantial investments in vaccination technologies, particularly mRNA vaccines, which are increasingly vital.
In summary, vaccination represents a social responsibility and a cornerstone of global health that must be safeguarded and promoted to ensure a healthier future for everyone. It transcends mere medical procedure; it is integral to the overall well-being of our communities and populations.
References
- Jenner E. An inquiry into the causes and effects of the variolae vaccinae, a disease discovered in some of the western counties of England, particularly Gloucestershire, and known by the name of the cow pox. London: Sampson Low, 1798.
- World Health Organization. The global eradication of smallpox: Final report of the Global Commission for the Certification of Smallpox Eradication. WHO, 1980.
- Plotkin SA, Orenstein WA. Vaccines, 6th ed. Saunders, 2014.
- Sadoff J, et al. Safety and Efficacy of the Ad26.COV2.S COVID-19 Vaccine. New England Journal of Medicine, 2021;384(14):1330–1341. https://doi.org/10.1056/NEJMoa2101544
- Centers for Disease Control and Prevention. Vaccine-preventable diseases, 2021. Retrieved from https://www.cdc.gov/vaccines/vpd/index.html
- Polack FP, et al. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. New England Journal of Medicine, 2020;383(27):2603–2615. https://doi.org/10.1056/NEJMoa2034577
- Weaver SC, Lecuit M. Chikungunya Virus and the Global Spread of a Mosquito-Borne Disease. New England Journal of Medicine, 2015;372(13):1231–1239. https://doi.org/10.1056/NEJMra1406035
- Regnault A, et al. The RTS,S/AS01 malaria vaccine and its impact on the burden of malaria in sub-Saharan Africa. Vaccine, 2018;36(39):5824–5833. https://doi.org/10.1016/j.vaccine.2018.08.019
- Intergovernmental Panel on Climate Change. Climate Change 2022: Impacts, Adaptation and Vulnerability. Cambridge University Press, 2022.
- Papi A, et al. Respiratory Syncytial Virus Prefusion F Protein Vaccine in Older Adults. New England Journal of Medicine, 2023;388(7):595–608. https://doi.org/10.1056/NEJMoa2212658
- World Health Organization. Measles outbreaks in Europe, 2019. Retrieved from https://www.who.int/emergencies/diseases/measles/outbreaks-europe
- Fine P, Eames K, Heymann DL. “Herd immunity”: A rough guide. Clinical Infectious Diseases, 2011;52(7):911–916. https://doi.org/10.1093/cid/cir075
