chronic carrier; persistent carrier of infection
Medical term for a person who continues to harbor and potentially transmit an infectious agent, especially hepatitis B or C, over a long period.
Chronic carriers of hepatitis B require regular checkups.
キャリア is a more general loanword for 'carrier' and can refer to carriers of genetic traits or diseases, while 持続感染者 specifically emphasizes persistent, long-term infection.
Compound of 持続 (persistence, continuation) + 感染者 (infected person). The term is a straightforward medical coinage.