Impact of 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

Background In 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. Methods We 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. Results The trend in POC-LFT activity was similar to PCR-positivity and hospitalisations trends across high, medium 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 = 0.014), and 6 days earlier peak of PCR-positivity. The 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 = 0.001). PCR-positivity was positively correlated to both hospitalisations and deaths, but with lags of 6 and 14 days respectively. Conclusions High 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 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.…”

“…Most of the studies comprised one‐off testing [29–31, 33, 35, 36, 38–45], indicating that testing was conducted only once for each participant. Four studies mentioned routine testing [32, 34, 41, 42], which implies regular and repeated testing of individuals.…”

“…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].…”

“…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].…”

“…Three studies examined the number of hospitalizations and deaths as outcomes [35,36,43]. Among these three studies, two also reported the rate of ICU admission [35,36], which indicates the proportion of COVID-19 cases requiring ICU care.…”