The current rise in cases in the United Kingdom shows traces of a sub-lineage of the Delta variant.
Many experts think B.1.617, or what has been called the Indian double mutation, is behind the surge.
Until nearly three months after the inoculation drive began, authorities were not checking if those getting tested for coronavirus had been vaccinated.
An expert reviews the evidence and explains how well does the vaccine work.
And other questions answered.
The research, studied 58 patients admitted to the Oxford University Hospitals, with moderate to severe symptoms.
Even if we do get a vaccine, it may just reduce the severity of symptoms or provide temporary protection. What happens then?
Getting immunised against Covid-19 might become routine – like going to the dentist.