Theres is M Virus and F Virus. Maeda is F Virus carier. Is F Virus stand for (Father or Female)? Sorry, I have this big leap of time no re-read the manga.
Yeah F virus stands for 'Father' and M for 'Mother'. The chapter with the doctor/scientist lady's back-story explains it. But from what I understand the M virus is the main carrier, and they infect others in search of someone with the capability of becoming an F virus carrier.
Never read this genre before.
So refreshing