Even if your child has been vaccinated, booster shots provide an extra layer of protection.
Every dollar spent on vaccines brings a 16-fold return on investment — and up to $44 for every dollar if broader benefits are taken into account.
The disease kills more than a million people a year but the world's response to it is totally inadequate.
The residents of a Nigerian village had no health services, save for traditional methods, to treat those with a fever and a rash.
Western anti-immunisation movements have taken root in local communities resulting in some parents refusing to vaccinate their children.