Japan's downgrade of the legal status of COVID-19 will likely deliver the economy a ¥4.2 trillion ($31 billion) boost, driven in part by an increase in the number of inbound tourists, according to an estimate by a private sector economist.

As of Monday, the coronavirus has begun to be treated the same as the seasonal flu, with the government relinquishing its legal authority to ask those who have tested positive to stay in hospital or to quarantine. Japan has already reopened its doors to foreign tourists after enforcing a stringent border control regime over the virus.

Of the ¥4.2 trillion estimated economic boost, Hideo Kumano, executive chief economist at the Dai-ichi Life Research Institute, said more than half, or around ¥2.6 trillion, will come from a revival of inbound tourism. Some ¥1.1 trillion will be generated by increased productivity, as people will be less frequently kept away from work under the new guidelines.