Cause 8: Insufficient Herd Immunity
Herd immunity is a protective shield built when a significant portion of the community is immune to a disease, either through previous infection or vaccination. It acts as a firewall, preventing the spread of the disease, even if a few cases occur.
However, for herd immunity to be effective, a high percentage of the population needs to be immune. If vaccination rates drop below this threshold, communities become vulnerable. This is especially concerning for those who cannot be vaccinated, such as infants or individuals with certain medical conditions.
Once the protective shield of herd immunity weakens, even a single case can lead to an outbreak. As the virus finds more and more susceptible hosts, it spreads rapidly, leading to a domino effect where one case leads to many.
While achieving a particular vaccination rate is crucial, herd immunity is also about distribution. Even within a community with an overall high vaccination rate, if there are pockets or clusters of unvaccinated individuals, they can act as a breeding ground for the virus.(8)
