The next day on 17 February, the Ministry of Health, Labour and Welfare confirmed 99 more cases, raising the total to 454, 33 of whom were crew members;[30][31] on 18 February, another 88 cases were confirmed, bringing the total to 542.[32] By late March it was stated that 712 of 3,711 people on the Diamond Princess, or 19.2% had been infected by COVID-19.[33][34] There is the possibility that quarantine in a cruise ship is dangerous, because the cruise ship does not use HEPA filters which can effectively screen 99 percent of the particles with a diameter of 3 microns or more, as is used in modern airplanes.[35]