The process by which an illness or symptoms become more severe (often used as 'to become severe'). Common in medical and public-health contexts.
高齢者は感染すると重症化しやすいと報告されている。
Reports indicate that elderly people are more likely to develop severe illness if infected.
早期治療が遅れると、症状が重症化するおそれがある。
If early treatment is delayed, there is a risk that symptoms will worsen into a severe condition.
病院のベッド数は重症化患者の増加を前提に計画されている。
The hospital's bed capacity is planned on the assumption of an increase in severely ill patients.