クルーズ船で新たに10人感染|NHK 首都圏のニュース
10 more cases on the 10 already infected from the ship = 20
Google translation might help

Feb 06 @ 09:01
According to the Ministry of Health, Labor and Welfare, as a result of conducting a virus test on people with symptoms and their close contacts on a cruise ship on which a Hong Kong man infected with the new coronavirus was on board, 10 people were infected.
Newly confirmed.So far, a total of 20 passengers have been confirmed infected with this cruise ship.
According to the Ministry of Health, Labor and Welfare, quarantine of about 3,700 passengers and all crew members were carried out on board the cruise ship Diamond Princess, and 120 people who had symptoms such as fever and cough, We have collected specimens from a total of 273 persons, including 153 persons who have been in close contact, and conducted virus tests sequentially.
On the 6th,
results for 71 new cases were found, and 10 of them were confirmed to have been infected with the virus.
The cruise ship will be berthing at the port of Yokohama, and the Ministry of Health, Labor and Welfare will send 10 newly infected individuals to medical institutions in Kanagawa Prefecture.
As a result, the number of infected passengers on the cruise ship has been confirmed to be 20 including the 10 confirmed on the 5th.
The Ministry of Health, Labor and Welfare has been requesting that approximately 3,700passengers and crew members remaining on board the ship be kept on board,
and in principle stay in the cabin for 14 days, as the inspection continues.