Developer of Sputnik V doesnât expect vaccineâs effectiveness parameters to change The press service of the Russian Healthcare Ministry reported that the ministry had made a decision to stop recruiting the volunteers for trials of the vaccine preparation MOSCOW, December 24. /TASS/. The obtained results of clinical trials of the Sputnik V vaccine against the coronavirus are sufficient to stop recruiting new volunteers. The planned parameters of effectiveness of the preparation have been reached and no further changes are expected, Director of the Gamaleya National Research Center for Epidemiology and Microbiology of the Russian Healthcare Ministry that developed the vaccine Alexander Gintsburg told TASS on Thursday.