What measures can protect communities from measles outbreaks?

Vaccination is the best way to protect individuals and communities from measles. It’s also the most effective way to curb an ongoing outbreak.

High rates of vaccination are important because of a phenomenon called herd immunity. When people who are vaccinated do not get infected, it essentially stops the spread of the virus, thereby protecting those who are most susceptible to getting sick. When herd immunity wanes, the risk of infection rises for everyone – and especially for the most vulnerable, such as young children and people who are immunocompromised.

Because measles is so contagious, estimates suggest that 95% of the population must be vaccinated to achieve herd immunity. Once vaccine coverage falls below that percentage, outbreaks are possible.

Having robust public health systems also provides protection from outbreaks and limits their spread. Public health workers can detect cases before an outbreak occurs and take preventive steps. During a measles outbreak, they provide updates and information, administer vaccines, track cases and oversee quarantine for people who have been exposed and isolation for people who are contagious.