"The step of RDIF on the proposal to boost the Pfizer vaccine" Sputnik Light "is quite logical, so that those who were vaccinated by Pfizer would be effectively protected by a wider range of antibodies as a result of boosting," RIA Novosti quoted Gunzburg as saying.
Pfizer's efficiency versus delta is probably 40%, he said, but there is no exact data yet.
Earlier, Gunzburg, in an interview with the NSN, told how herd immunity is formed.