We often think of vaccination as individual protection. It is also, and this is essential, a collective protection. The concept of herd immunity explains how vaccinating enough of the population protects everyone, including people who cannot be vaccinated. A solidarity mechanism that deserves to be understood.
1. The principle of collective immunity
A germ spreads by passing from person to person. When a sufficient portion of the population is immunized, the microbe encounters fewer receptive people and circulates much less. Its spread is slowed, which indirectly protects the entire community.
2. Protect the most fragile
Some people cannot be vaccinated or are poorly protected: infants who are too young, immunocompromised people, certain pathologies. Collective immunity protects them by limiting the circulation of the microbe around them. Getting vaccinated thus becomes a gesture of solidarity.
| Protected person | Why she depends on others |
|---|---|
| Infants | Too young for some vaccines |
| Immunocompromised | Reduced vaccine response |
| Frail people | Increased risk of complications |
3. A threshold to reach
To be effective, herd immunity requires that a sufficient proportion of the population be immune. This threshold varies depending on the diseases, particularly their contagiousness. If coverage drops, the microbe can begin to circulate again, as we have seen with some diseases that reappear.
4. An individual and collective issue
Getting vaccinated therefore means protecting yourself twice: yourself and others. This collective dimension gives additional meaning to vaccination. Maintaining good vaccination coverage is a public health issue that depends on everyone’s choices.
- Herd immunity slows down the circulation of microbes
- It protects those who cannot be vaccinated
- It requires sufficient vaccination coverage
Understanding herd immunity sheds light on the solidarity-based scope of vaccination. The doctor can answer questions.
💡 tips to remember
- When a sufficient part of the population is immune, the microbe circulates much less: this is collective immunity.
- It protects people who cannot be vaccinated: infants, immunocompromised people, fragile people.
- Getting vaccinated thus becomes a gesture of solidarity, beyond of individual protection.
- Herd immunity requires sufficient coverage: if it drops, certain diseases can reappear.
- Getting vaccinated protects twice: oneself and others, which gives additional meaning to vaccination.
