Impact of a national-scale targeted point-of-care symptomatic Lateral Flow Testing on trends in COVID-19 infections, hospitalisations and deaths during the second epidemic wave in Austria (REAP3)

Abstract

BackgroundIn October 2020, amidst the second COVID-19 epidemic wave and before the second-national lockdown, Austria introduced a policy of population-wide point-of-care lateral flow antigen testing (POC-LFT). This study explores the impact of this policy by quantifying the association between trends in POC-LFT-activity with trends in PCR-positivity (as a proxy for symptomatic infection), hospitalisations and deaths related to COVID-19 between October 22 and December 06, 2020. MethodsWe stratified 94 Austrian districts according to POC-LFT-activity (number of POC-LFTs performed per 100,000 inhabitants over the study period), into three population cohorts: (i) high(N=24), (ii) medium(N=45) and (iii) low(N=25). Across the cohorts we a) compared trends in POC-LFT-activity with PCR-positivity, hospital admissions and deaths related to COVD-19; b) compared the epidemic growth rate before and after the epidemic peak; and c) calculated the Pearson correlation coefficients between PCR-positivity with COVID-19 hospitalisations and with COVID -19 related deaths. ResultsThe trend in POC-LFT activity was similar to PCR-positivity and hospitalisations trends across high, medum and low POC-LFT activity cohorts, with association with deaths only present in cohorts with high POC-LFT activity. Compared to the low POC-LFT-activity cohort, the high-activity cohort had steeper pre-peak daily increase in PCR-positivity (2.24 more cases per day, per district and per 100,000 inhabitants; 95% CI: 2.0-2.7; p<0.001) and hospitalisations (0.10; 95% CI: 0.02, 0.18; p<0.15), and 6 days earlier peak of PCR-positivity. Th high-activity cohort also had steeper daily reduction in the post-peak trend in PCR-positivity (-3.6; 95% CI: -4.8, -2.3; p<0.001) and hospitalisations (-0.2; 95% CI: -0.32, -0.08; p<0.05). PCR-positivity was positively correlated to both hospitalisations and deaths, but with lags of 6 and 14 days respectively. ConclusionsHigh POC-LFT-use was associated with increased and earlier case finding during the second Austrian COVID-19 epidemic wave, and early and significant reduction in cases and hospitalisations during the second national lockdown. A national policy promoting symptomatic POC-LFT in primary care, can capture trends in PCR-positivity and hospitalisations. Symptomatic POC-LFT delivered at scale and combined with immediate self-quarantining and contact tracing can thus be a proxy for epidemic status, and hence a useful tool that can replace large-scale PCR testing.

Effectiveness of SARS‐CoV‐2 testing strategies: A scoping review

“…Among the 17 included studies, six were published in 2021 [29–34], and the remaining 11 studies [35–45] were published in 2022. The study design of the included studies were randomized controlled trials [32, 34, 41], nonrandomized experimental studies [31, 33, 36], cohort studies [35, 42, 43], cross‐sectional studies [38–40, 44], self‐controlled case series (SCCS) [30], and economic evaluations [29, 37, 45]. Among the randomized controlled trials, two were cluster randomized controlled trials [32, 34].…”

“…Six of the studies considered symptomatic and asymptomatic individuals [29, 31, 33, 38, 39, 42], of which three studies also considered asymptomatic contacts [33, 39, 42]. Two studies focused on asymptomatic contacts only [32, 41], four studies focused on symptomatic individuals only [35, 36, 40, 43], one study focused on both symptomatic individuals and asymptomatic contacts [44], two studies focused on asymptomatic individuals only [34, 45], and two studies did not specify symptom status [30, 37]. Only one study specifically mentioned healthcare workers as participants, in addition to the general community [38].…”

“…Most studies ( n = 8) were conducted in healthcare facilities [29, 30, 35, 36, 40, 43–45]. Four studies were conducted in the community [31, 33, 39, 41].…”

“…Three studies focused on children only [33, 40, 44]. Six studies considered both adults and children [31, 32, 34, 39, 42, 43], of which four reported the outcomes for children and adults separately [34, 39, 42, 43]. Two studies did not specify the age of the participants [37, 45].…”

“…Among the included studies, 14 used RT‐PCR [29–31, 33–42, 44] and 10 studies used antigen‐detecting RDT [29, 32, 33, 35, 39, 41–45]. None of the studies mentioned using test‐based screening strategies using NAAT other than RT‐PCR.…”