Similar to Elimination, a warm up is present, except it lasts 10 seconds and is shown by an additional Infection in ## s message. At regular intervals, the racer in last place becomes infected. Alternatively, a racer can become infected by touching another infected racer, even if that racer has been wrecked while infected. Infected racers have their cars rendered visually green and have a much more powerful and infinite nitro (e.g. a maxed out McLaren P1 is capable of reaching 259.1 mph / 417.3 km/h with full power nitro on, but when infected, it can reach speeds of up to 281.4 mph / 453.0 km/h). Their place numbers are also colored green and marked as green biohazard symbols on the map. Veins appear (blinking at a normal pace) around the screen, and the farther the center from the screen, the greener the vision.
All infected racers not in last place always start with a 30-second timer (except if they have been infected by knocking down another infected racer, in which case they get a 35-second timer instead). When that timer runs out, the infected racer suffers an Infection Overload (known as an INFECTION CRASH in the Japanese language version of the game), wrecking and then respawning cured. When an infected racer has 00:09:999 or lower, the veins start flashing very rapidly as a warning sign. An Infection Overload counts as a Wreck, and therefore prevents a Perfect Race from being obtained. The player's normal arrow icon also becomes a skull like any wrecked racer would on the map.
Regardless of the number of racers, all Infected events disable the traffic completely (except for a stationary magenta bus in Tokyo and a blockade of three police cars in Tokyo Reverse. These can be Near Missed, Traffic Controlled, or Traffic Downed). Also, as of the San Diego Harbor update, a new event in Season 5 requires the use of one specific car: the Mercedes-Benz CLK GTR AMG. All other Infected events require the use of a car from a specific class.
Along with Classic, Infected is a race mode used in time-limited events.