Pay attention to the ‘yellow effect’, a color that now characterizes all of Italy. “With the reopening it is also possible a new growth of the contagion curve, if there are not the necessary precautions”. Fabrizio Pregliasco, a virologist at the State University of Milan, warns, who explains to Adnkronos Salute: “We have known a lot about this virus in a short time, but it can still escape us, I believe that caution, systematicity and progression in openings is fundamental”. Attention is needed, explains Pregliasco, “because it is possible that there may not be a new wave but, more likely, a rising wave of infections”. It is mathematical “with the reopening – he continues – contacts increase and therefore the probability of meeting a person positive for the virus. According to yesterday’s data, the positives in Italy were 281 thousand. those not identified, are at least double. So there are over half a million positive people that it is possible to meet with the greatest mobility. It is also possible that a vaccinated could be positive and could maintain a chain of contagion “. For all these reasons “it will therefore be possible to see a slight rise in the curve, depending on the progression of the openings, consequent to the number of contacts even if, fortunately, there will not be the same proportionality on serious cases thanks to vaccines”, concludes Pregliasco inviting us not to abandon protective measures – distance, mask, hygiene – “this will gradually allow for greater freedom”.