To build up a collective defense against coronavirus, about 80% of Bulgarians must acquire immunity. This became clear from the comment of the virologist Prof. Radostina Alexandrova on bTV.

"To build herd immunity against the virus, it takes at least 60-70% of inoculated population. With the advent of new strains it is believed that this percentage should be even higher – up to 80%. Not only Bulgaria, but the whole world is still far away from that," the specialist explained.

Prof. Alexandrova told of the Johnson & Johnson vaccine, which was authorized in the US a few days ago.

In her words, the vaccine resembles that of AstraZeneca, as it is also vector-based, but the difference is that it is administered in one dose only and showed higher efficacy rate. This is a one-dose vaccine, unlike the others, and is stored at more normal low temperatures than Pfizer and Moderna "It prevents more than 85% of severe cases,” the professor explained.

This week, Johnson & Johnson is to ship 4 million doses of its vaccine to the United States. The delivery of another 16 million doses is scheduled for the end of March.

"Already during clinical trials, Johnson & Johnson entered into a direct battle with the new variants of the virus. Another advantage is that it can be stored for 3 months in a regular refrigerator," the expert added.

Professor Alexandrova believes that this is a pandemic that cannot be tackled with one vaccine, one institution or one country. The more vaccines there are, the better, she noted