Cuban researcher highlights advantages of intervention studies Cuban researcher highlights advantages of intervention studies Havana, May 3 (Prensa Latina) Intervention studies with Cuba's Covid-19 vaccine candidates have the advantage of resembling what would happen when the vaccine, once registered, is administered at field level, experts explained on Monday. Dr. Sonia Resik, principal researcher of these studies with the Abdala vaccine candidate, spoke about the characteristics of this research process and its differences with clinical trials, as well as the advantages of the population-based intervention, at a press conference. 'Controlled intervention studies differ from clinical trials in that there is no randomization of the subjects who participate in it, that is, there is no control group. You have as a control group the same population group that is not vaccinated, who do not participate in the controlled trial,' the expert from the Pedro Kouri Institute of Tropical Medicine (IPK) explained.