A vaccine preventable disease (VPD) is an infectious disease caused by viruses or bacteria that can be prevented with vaccines.
Vaccines are a crucial tool in public health, offering protection against a range of potentially serious and sometimes fatal diseases. These diseases, now commonly referred to as vaccine-preventable diseases, highlight the transformative impact of immunization. Let's explore this concept in more detail:
Understanding Vaccine Preventable Diseases
Vaccine-preventable diseases (VPDs) are infections caused by:
- Viruses: Examples include measles, mumps, rubella, polio, and influenza.
- Bacteria: Examples include diphtheria, tetanus, pertussis (whooping cough), and Haemophilus influenzae type b (Hib).
The defining characteristic of these diseases is that effective vaccines exist to prevent infection or significantly reduce the severity of illness.
How Vaccines Prevent Disease
Vaccines work by stimulating the body's immune system to produce antibodies that recognize and fight off the specific virus or bacteria.
- Exposing the Body: Vaccines introduce a weakened or inactive form of the disease-causing agent (or a part of it) into the body.
- Immune Response: This prompts the immune system to create antibodies.
- Future Protection: If the individual is later exposed to the actual disease, the immune system is primed to quickly recognize and neutralize the threat, preventing or lessening the severity of the illness.
Examples of Vaccine Preventable Diseases
The following are some of the most common and impactful vaccine-preventable diseases:
| Disease | Causative Agent | Potential Complications |
|---|---|---|
| Measles | Virus | Pneumonia, encephalitis (brain inflammation), death |
| Mumps | Virus | Meningitis, encephalitis, deafness, infertility |
| Rubella | Virus | Miscarriage or birth defects in pregnant women |
| Polio | Virus | Paralysis, death |
| Diphtheria | Bacteria | Breathing difficulties, heart failure, nerve damage, death |
| Tetanus | Bacteria | Muscle spasms, breathing difficulties, death |
| Pertussis | Bacteria | Pneumonia, seizures, brain damage, death (especially in infants) |
| Haemophilus influenzae type b (Hib) | Bacteria | Meningitis, pneumonia, epiglottitis, death |
The Importance of Vaccination
Vaccination is one of the most effective public health interventions available. The benefits of vaccination extend beyond individual protection:
- Community Immunity (Herd Immunity): When a significant portion of the population is vaccinated, it creates a buffer of protection for those who cannot be vaccinated (e.g., infants, immunocompromised individuals). This is known as herd immunity.
- Disease Eradication/Elimination: Through widespread vaccination efforts, some diseases have been eradicated (e.g., smallpox) or eliminated from specific regions (e.g., polio in most of the world).
- Reduced Healthcare Costs: Preventing diseases through vaccination reduces the burden on healthcare systems by decreasing the number of hospitalizations, doctor visits, and treatments required.
