Why are breakthrough Covid-19 cases rising?

The reports of fully vaccinated people testing positive for Covid-19 has caused concern for the authorities around the world who were depending on vaccination to contain the virus surge.
While the ‘breakthrough’ Covid-19 cases raise questions about the efficacy of vaccines, especially against the highly contagious Delta variant, health experts have said that they are not a cause for alarm. Watch the full report to find out why breakthrough cases are on the rise.