According to analysis carried out by Imperial College London, the country could be set for a large increase in deaths within three weeks of partially lifting its social-distancing restrictions.
Currently, Italy has the second highest-death rate in Europe, with 29,315 deaths, behind 29,502 in the UK.
But researchers from Imperial have forecast a second spike will take place if the country returns to just 20% of its pre-lockdown mobility levels – a measure of how much people leave the home.
The study warned that several social-distancing measures will need to remain in place if a sudden rise in deaths is to be avoided.
It also recommended the use testing, contact-tracing and self-isolation of people displaying symptoms to stop the virus spreading again.
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Dr Samir Bhatt, from Imperial’s School of Public Health, praised the Italian authorities for their response to the pandemic, but said the worst could be yet to come.
“The impact of COVID-19 on Italy has been tragic but the response taken to limit the impact of the disease has been successful and disease control has been substantively achieved,” he said.
“Unfortunately, continued social distancing and other measures are required to prevent this success from being rapidly reversed and our work provides a warning against underestimating the importance of such sacrifice.”
And Dr Michaela Vollmer said: “Even small changes in mobility will most likely lead to a resurgence of deaths and the occurrence of a second wave which may be even greater than what Italy has already experienced.”
Over four million Italians returned to work on Monday after seven weeks of lockdown measures.
People in the country are now allowed to visit family members and people with whom they have an "established emotional bond" in the same region.
Parks have also been reopened for people to go running in, and people are allowed to travel large distances to exercise.
Social gatherings are still banned and it is mandatory to wear a mask on public transportation and in closed public spaces.
But the ban on funerals has also been relaxed, with a maximum of 15 mourners allowed to attend.