MOSCOW, May 21. /TASS/. The coronavirus situation in Russia is till unpredictable, President of the Russian Academy of Sciences Alexander Sergeyev told TASS.

"The situation is very unpredictable in terms of the epidemic development. The right approach to easing quarantine measures is to be based on the mortality rate when we really see that mortality is decreasing. So far, the situation is risky because the mortality is not going down and it causes serious concerns," he said.

According to Sergeyev, a vaccine against the coronavirus should not be expected soon. "The process of a vaccine development is quite long. We will have to wait for it at least several months. And even if pre-clinical tests yield positive results it doesn’t guarantee that it will demonstrate such results during clinical tests," he said.

In his words, combating the coronavirus infection is a "classical managerial task in conditions of uncertainty." "Obviously, it is important to move forward (in easing coronavirus lockdowns - TASS) by small steps, to react swiftly to the changing situation when the economy is revived. Delicate management with swift reaction to feedback is needed. But in these conditions stemming from the specifics of the coronavirus (symptomless cases, long incubation period), it is difficult to plan anything," he said.