I need to re-write my earlier posting, which is not 100% accurate:
Beginning on August 31 (arrivals in Italy after 12:01 a.m. Italy time):
BOTH of the following will be required to enter Italy if coming from Canada, Japan, the United States or the United Kingdom (or if having stayed in or transited through those countries in the 14 days prior to entering Italy):
(i) negative Molecular or Antigen Covid-19 test result collected no more than 72 hours prior to ARRIVAL in Italy (48 hours in the case of entry from the U.K.); AND
(ii) proof of FULL vaccination with an approved vaccine at least 14 days prior to arrival in Italy, OR proof of having recovered from Covid-19 in the timeframes allowed (and subject to specified content and format of recovery information).
Failure to satisfy BOTH of the above requirements will result in mandatory fiduciary self-isolation for 5 days, followed by a SECOND Covid-19 test at the conclusion of the period of self-isolation. Note that (i) is non-waivable (except for children under age 6). I assume that children between 6 and 12 (who cannot presently be vaccinated) need only satisfy (i) as long as traveling with a fully vaccinated and tested parent or guardian (unfortunately, this is not expressly stated). Children age 12 and above (who can be vaccinated) are treated exactly as adults.
Please also note that airlines MAY impose more stringent requirements to board flights to Italy (for safety or corporate policy reasons) than those imposed by the Italian Government. For example, an airline COULD deny boarding to a non-vaxxed passenger who refuses to get vaccinated despite being eligible (i.e. over age 12), OR to a vaxxed passenger who has not gotten a negative test result, even though the Italian Entry Regulations WOULD allow such person to enter Italy, subject to the 5-day self-isolation requirement.
See this updated webpage of the Italian Embassy in Washington D.C.:
Entry into Italy from the United States of America
ambwashingtondc.esteri.it
Please be careful in relying on some other official websites purporting to give the current Italian Entry Requirements. Some of these are either outdated, incomplete, confusing, muddled or plain incorrect. The Italian Embassy website hyperlinked above is current and accurate.