Translation guide
The proportion of a population that becomes infected with a disease over a specific period. In Japanese, this is most commonly expressed as 感染率 (kansenritsu), but other terms like 罹患率 (rikanritsu) and 感染割合 (kansen wariai) are used in specific contexts.
The percentage or proportion of people infected in a population.
The most common and general term for infection rate. Used in news, medical reports, and everyday conversation about disease spread.
この地域の感染率は先月より上昇した。
The infection rate in this area has risen since last month.
感染率を下げるためにマスク着用が推奨されている。
Wearing masks is recommended to reduce the infection rate.
A more technical term often used in epidemiology to mean 'attack rate' or 'incidence proportion'. It refers to the proportion of a defined population that contracts the disease during a specified time interval.
インフルエンザの罹患率は今年特に高い。
The influenza attack rate is particularly high this year.
Literally 'infection proportion'. Used when emphasizing the ratio or share of infected individuals, often in more descriptive or less technical contexts.
全人口に対する感染割合はまだ低い。
The proportion of infections relative to the total population is still low.
Means 'prevalence rate', the proportion of a population that has the disease at a specific point in time. Not exactly 'infection rate' but sometimes used in similar contexts. Important to distinguish from incidence.
この病気の有病率は高齢者で高い。
The prevalence rate of this disease is high among the elderly.
The number of new cases occurring in a population over a specific period.
Incidence rate; the number of new cases per population at risk in a given time period. Common in epidemiological reports.
新規感染の発生率は減少傾向にある。
The incidence rate of new infections is on a downward trend.
Literally 'new infection rate'. Used in news and public health communications to refer to the rate of newly confirmed cases.
新規感染率が再び上昇している。
The rate of new infections is rising again.
How fast an infection spreads, often expressed as a reproduction number or growth rate.
The pace of infection spread. Natural when discussing the speed of an outbreak rather than a strict percentage.
感染拡大のペースが加速している。
The pace of infection spread is accelerating.
Effective reproduction number (Rt). A technical term used in epidemiology to indicate the average number of secondary infections per case at a given time. Often referred to in news as '感染率' loosely, but it's a specific metric.
実効再生産数が1を超えると感染が拡大する。
When the effective reproduction number exceeds 1, infections spread.
感染率 (kansenritsu) is the general term for infection rate. 罹患率 (rikanritsu) is a technical term for attack rate, often used in outbreak investigations. 有病率 (yuubyouritsu) means prevalence, the proportion of existing cases at a point in time, not the rate of new infections. Use 感染率 for most everyday and news contexts.
When stating a specific percentage, attach ％ directly after the number, e.g., 感染率は5％ (the infection rate is 5%). The word 割合 (wariai) can also be used: 感染割合は5割 (the infection proportion is 50%).
市内の感染率は大幅に低下した。
The infection rate in the city has dropped significantly.
現在の感染率はどのくらいですか？
What is the current infection rate?