14% of those vaccinated in Bulgaria become re-infected with coronavirus. Measures are needed against counterfeit vaccination certificates. The hospitalized patients who have a document that they have been vaccinated against Covid-19 should be tested to see if this is true, Prof. Todor Kantardzhiev has told the Bulgarian National Radio.

The former head of the National Center for Infectious and Parasitic Diseases and current health expert of the Sofia Municipality commented that this has not been done so far, although it has been offered for a long time.

"Delta Plus is not a new strain, but a sub-variant of the Indian variant. There is nothing scary about it, nothing dangerous, nothing different in the course of the disease. It is neither more deadly, nor it is more aggressively spreading," the professor said.