CLIL 英文: 佛系防疫，積極防疫與封城
Herd Immunity, Optimal Containment, & Lockdown 蘇正隆
美國全國廣播新聞網《NBC News》在 What Taiwan can teach the world on fighting the coronavirus? 的新聞中指出，台灣在得知中國武漢開始傳播「嚴重肺炎」的消息，立即採取積極的防疫措施。這種主動出擊、積極圍堵的策略，英文叫 optimal containment。
面對新冠病毒肺炎疫情，3月初英國首相強森 (Boris Johnson) 原本採取低度防疫作為 (lax infection prevention and control practices)，想讓全民自然感染，達到群體免疫 (herd immunity) 的效果，因此遭譏為「佛系抗疫」。佛系是中文新生流行語，意思是指順其自然、怎麼都無所謂的態度。如：「…又一個什麼都不做，什麼都不 care 的佛系青年…」。
… the virus will be defeated once a majority of the population gets infected and develops an immunity to the disease. This so-called “herd immunity” strategy sparked emotional debate in the U.K. after it was outlined by Prime Minister Boris Johnson.
群體免疫的理論是感染病毒的人會產生抗體，當約60% 的人都染病之後，整個社群就有免疫力，屆時新冠病毒肺炎的威脅自然就降低。低度防疫/佛系抗疫可能會造成疫情難以收拾，拖垮醫療照顧體系，後來英國改弦易轍，採取較嚴厲的措施。
Herd immunity occurs when a large percentage of a population has become immune to an infection. In such a setting, chains of infection are likely to be disrupted, thus stopping the spread of a disease.
美國 National Bureau of Economic Research 針對新冠病毒肺炎外部成本發表研究報告 (COVID-19 infection externalities: Herd immunity versus containment strategies, Bethune & Korinek, 3 May, 2020)，指出若未採取防疫措施，只等群體免疫，會重創經濟，數年才會恢復。
In the absence of public health interventions, the disease will not be overcome until 60% herd immunity is acquired. In this scenario, the resultant reduction in economic activity will lead to a sharp recession and a slow recovery that could take several years to complete.)
若採取積極主動的防疫作為，隔離感染者，追蹤接觸者等，對經濟的衝擊較小，幾個月後可恢復接近正常。
By targeting the high-risk population, isolating the infected, and conducting a program of widespread testing and effective contact-tracing, the outbreak can be quickly contained. In this scenario, only mild restrictions need be imposed on the general population, and economic activity could return to something close to normal within months.
而採取激烈盲目的封城 (blind containment/lock down) 呢？
會造成經濟長期衰退，而每一感染病例的社會成本高達 $576,000 美元，遠遠高於積極主動的防疫。
If public health authorities cannot isolate the infected, it becomes necessary to lock down the entire population. Such measures will lead unavoidably to a severe and long-lasting economic recession. In a locked down environment, the estimated cost of each additional infection is $576,000 ─ much higher than that of the optimal containment strategy.
很高興我們台灣採取了對的策略。 (Jerome Su, May 14, 20, Revised May 18, 20)