Appendix 6—table 1. Investigating the relation between the date of ‘lockdown’ and the date that the estimated $R_e$ dropped below 1.

The first three columns contain the same information as the first four columns of the main text Table 1. The last two columns are analogous to the third (‘${\displaystyle {\hat{R}}_e<1}$ based on confirmed cases’) but are based on $R_e$ estimates for hospitalisations and deaths respectively. For each of these observation types, we used our method to determine when the $R_e$ estimate first dropped below 1, and for which dates the corresponding 95% confidence interval contained 1. Further, we used news reports to determine when a country implemented stay-at-home orders (a ‘lockdown’). Based on our $R_e$ estimates for confirmed cases, Denmark, Germany, the Netherlands, and Slovenia had 95% confidence intervals that included or were below one before a nationwide lockdown was implemented. For $R_e$ estimates based on COVID-19 deaths, there are also four: Denmark, the Netherlands, Poland, and the United Kingdom. See Appendix 2 for smoothing related caveats.

Country	Lockdown	${\displaystyle {\hat{R}}_e<1}$ based on Confirmed cases	${\displaystyle {\hat{R}}_e<1}$ based on Deaths	${\displaystyle {\hat{R}}_e<1}$ based on Hospitalisations
Austria	16–03	20–03 [20-03, 20-03]
Belgium	18–03	30–03 [25-03, 03-04]	26–03 [24-03, 26-03]	25–03 [24-03, 25-03]
Denmark	18–03	10–03 [10-03, 20-06]	22–03 [18-03, 07-01]
Finland	16–03	02–04 [29-03, 30-04]	07–04 [25-03, 11-04]
France	17–03	27–03 [23-03, 07-04]	24–03 [22-03, 26-03]	27–03 [25-03, 26-03]
Germany	22–03	18–03 [17-03, 19-03]	31–03 [23-03, 04-04]
Ireland	27–03	08–04 [04–04, 15–04]	05–04 [31-03, 09-04]	06–04 [06–04, 26–04]
Italy	10–03	18–03 [17-03, 19-03]	14–03 [01–03, 29–05]
Netherlands	23–03	05–04 [22-03, 10-04]	22–03 [19-03, 02-04]	26–03 [24-03, 26-03]
Norway	14–03	21–03 [17-03, 24-03]	25–03 [18-03, 08-04]
Poland	25–03	02–04 [31-03, 17-04]	09–04 [24-03, 01-12]
Portugal	16–03	28–03 [23-03, 15-04]	28–03 [21-03, 12-04]
Romania	24–03	06–04 [31-03, 29-04]	17–04 [25-03, 28-04]
Russian Federation	30–03	04–05 [01–05, 08–05]	18–05 [14-05, 12-12]
Slovenia	20–03	23–03 [13-03, 26-03]	26–03 [20–03, ≥03-05-2021]
Spain	14–03	26–03 [25-03, 26-03]
Sweden		01–04 [06–03,≥03-05-2021]	05–04 [13–03,≥03-05-2021]
Switzerland	17–03	22–03 [20-03, 22-03]	21–03 [18-03, 23-03]	18–03 [16-03, 18-03]
Turkey	21–03	08–04 [01–04, 13–04]	04–04 [31-03, 06-04]
United Kingdom	24–03	30–03 [28-03, 20-04]	25–03 [24-03, 25-03]	29–03 [27-03, 29-03]