Comiskey Catherine, Snel Anne, Banka Prakashini
School of Nursing and Midwifery, Trinity College Dublin, The University of Dublin, Dublin, 2, Ireland.
HRB Open Res. 2022 Feb 25;4:19. doi: 10.12688/hrbopenres.13206.2. eCollection 2021.
Since the first case of COVID-19 in Ireland was recorded policy makers have introduced mitigation measures to control the spread of infection. Infection is spread by both known cases and hidden, undetected asymptomatic cases. Asymptomatic individuals are people who transmit the virus but display no clinical symptoms. Current evidence reveals that this population is a major contributing factor to the spread of the disease. There is little or no knowledge of the scale of the hidden prevalence of all infections both asymptomatic and symptomatic in Ireland. Furthermore, as governments plan for the roll out of imminent immunisation programmes, the need to know the scale of the hidden prevalence and hence knowledge of the level of immunisation required is essential. We describe and analyse the numbers of reported cases of COVID-19 in Ireland from the first case in February 2020 to mid-December 2020. Using the method of back-calculation we provide estimates of the asymptomatic prevalence of cases from June to December 2020. The descriptive analysis highlighted two epidemic waves of known cases in the time period. Wave two from June to December included twice as many cases as wave one and cases were significantly younger. The back-calculation estimates of asymptomatic prevalence during this time period revealed that for every case known there was an additional unknown case and total prevalence in wave two was estimated to be approximately 95,000 as opposed to the reported 48,390 cases. As prevalence in wave two is known to be spreading within and from younger age groups the role of mixing patterns on spread needs to be disseminated to the wider public to adequately inform them how personal modifications in behaviour can contribute to the control of the epidemic. While universally imposed lockdowns and mitigation measures may be essential, personal behavioural mixing choices are powerful protectors.
自爱尔兰记录到首例新冠肺炎病例以来，政策制定者已出台缓解措施以控制感染传播。感染是由已知病例和隐匿的、未被检测出的无症状病例传播的。无症状个体是指传播病毒但无临床症状的人。目前的证据表明，这一群体是疾病传播的主要促成因素。对于爱尔兰所有无症状和有症状感染的隐匿流行规模，人们知之甚少或几乎一无所知。此外，随着各国政府计划推出即将实施的免疫计划，了解隐匿流行规模以及因此所需的免疫水平至关重要。我们描述并分析了2020年2月首例病例至2020年12月中旬爱尔兰报告的新冠肺炎病例数。使用反向推算方法，我们提供了2020年6月至12月病例无症状流行率的估计值。描述性分析突出了该时间段内已知病例的两波疫情。6月至12月的第二波病例数是第一波的两倍，且病例明显更年轻。该时间段内无症状流行率的反向推算估计显示，每有一例已知病例，就有一例额外的未知病例，第二波的总流行率估计约为95000例，而报告的病例数为48390例。由于已知第二波疫情在较年轻年龄组内部和之间传播，传播中的混合模式作用需要向更广泛的公众传播，以便充分告知他们个人行为改变如何有助于控制疫情。虽然普遍实施的封锁和缓解措施可能至关重要，但个人行为混合选择也是有力的保护措施。
