Introduction
Vaccination and Public Health are deeply connected. Each year, vaccines prevent 3.5–5 million deaths worldwide by preparing the immune system to fight dangerous pathogens without causing disease [1]. From measles to hepatitis, they shield individuals and communities from devastating outbreaks.
This blog highlights the most common vaccines in human medicine, the diseases they prevent, how they are administered, and why they remain essential for global health [2].
But can societies maintain progress against deadly diseases without sustaining high vaccination coverage?
Measles, Mumps, and Rubella (MMR) Vaccine and Public Health Impact
The MMR vaccine protects against measles, mumps, and rubella.This live attenuated vaccine is given subcutaneously. Two doses provide about 97 percent protection against measles and 88–95 percent against mumps and rubella [4]. Global coverage was 86 percent in 2020, yet outbreaks still occur where uptake is low [2].
Influenza (Flu) Vaccine: Seasonal Protection for Communities
Influenza is a highly contagious respiratory illness. Annual vaccination is necessary because strains change frequently. The inactivated vaccine is given intramuscularly, while the live attenuated version is given intranasally. Effectiveness ranges from 40 to 60 percent depending on the match between vaccine and circulating strains [2]. As a result, health agencies recommend yearly vaccination. In the United States, about half of the population receives the flu vaccine each year, with higher uptake in older adults and healthcare workers [3].
Human Papillomavirus (HPV) Vaccine and Cancer Prevention
The HPV vaccine prevents several cancers and genital warts. This recombinant subunit vaccine is given intramuscularly. It offers 97–100 percent protection against the main cancer-causing HPV strains [2]. Moreover, countries with high vaccination coverage, such as Australia and the United Kingdom, have already seen major declines in cervical cancer [2].
Tetanus, Diphtheria, and Pertussis (Tdap) Vaccine
The Tdap vaccine protects against three serious bacterial infections. It contains toxoids for tetanus and diphtheria and inactivated bacteria for pertussis. Clinicians administer it intramuscularly, and it provides 80–90 percent protection. However, it requires booster doses every ten years [2]. Global coverage is high, but pertussis outbreaks still occur when uptake falls [3].
Hepatitis B Vaccine
The hepatitis B vaccine prevents infection linked to chronic liver disease and cancer. Clinicians give this recombinant subunit vaccine intramuscularly, and it provides about 95 percent protection when patients complete the three-dose series [2]. By 2020, 85 percent of infants worldwide had received it, significantly reducing transmission in high-prevalence regions [2].
Polio Vaccine
Polio once paralyzed hundreds of thousands of children each year but is now close to eradication. Two vaccines are used: inactivated polio vaccine (IPV), given by injection, and oral polio vaccine (OPV), which is live attenuated. Since 1988, cases have declined by more than 99 percent [5]. Today, only Afghanistan and Pakistan continue to report endemic transmission [5].
Varicella (Chickenpox) Vaccine
The varicella vaccine prevents chickenpox, once an almost universal childhood disease. Clinicians administer this live attenuated vaccine subcutaneously. Two doses provide about 90 percent protection [2]. Consequently, routine vaccination has reduced cases by 90 percent in countries such as the United States and United Kingdom [2].
Types of Vaccines in Human Medicine
Vaccines differ in their composition but share the goal of stimulating immunity. Live attenuated vaccines, such as MMR and varicella, provide strong, long-lasting protection. Inactivated vaccines, such as IPV and hepatitis A, are safe for immunocompromised patients but often require boosters. In addition, subunit and recombinant vaccines, including HPV and hepatitis B, use only parts of the pathogen to trigger immunity. Toxoid vaccines, such as tetanus and diphtheria, neutralize bacterial toxins. Finally, mRNA vaccines, such as those developed for COVID-19, instruct cells to produce viral proteins [2].
Routes of Vaccine Administration
Most vaccines are administered intramuscularly, including influenza, hepatitis B, and Tdap. Subcutaneous injection is used for MMR and varicella. Oral administration is used for polio campaigns, while intranasal sprays are available for live attenuated influenza vaccines [2].
Conclusion
Vaccination and Public Health are inseparable. From the near-eradication of polio to the prevention of cancers through HPV vaccination, immunization remains one of the most effective tools in medicine [1][2]. By improving vaccine access, addressing misinformation, and maintaining high coverage, societies can protect individuals and build resilient communities.
Vaccines are not just medical tools. They are the foundation of global well-being, ensuring that today’s children and future generations inherit a safer and healthier world.
References
- World Health Organization (2025) Vaccination prevents 3.5–5 million deaths annually. Available at: https://www.who.int/health-topics/vaccines-and-immunization/know-the-facts
- World Health Organization (2025) Immunization coverage fact sheet. Available at: https://www.who.int/news-room/fact-sheets/detail/immunization-coverage
- Centers for Disease Control and Prevention (CDC) (2025) Fast Facts on Global Immunization. Available at: https://www.cdc.gov/global-immunization/fast-facts/index.html
- Vaccine Knowledge Project (2025) MMR vaccine effectiveness rates. Available at: https://vaccineknowledge.ox.ac.uk/mmr-vaccine
- Global Polio Eradication Initiative (GPEI) (2025) Since 1988, GPEI has reduced polio cases by over 99%. Available at: https://polioeradication.org/wp-content/uploads/2025/04/GPEI_generalfactsheet_25-April-2025.pdf
