On February 27, 2020, Denmark had the first confirmed case of COVID-19 (indicator patient). The Danish health care authorities observed a steep rise in the number of confirmed cases, with a daily doubling in the number of cases from March 8–11. On March 12, the strategy officially changed from containment and suppression to mitigation and preparation. On March 14, the first official mortality due to COVID-19 was confirmed.
The EMS call volume
Overall calls volume for Copenhagen EMS was increased by 24% in the period, mostly to the coronavirus hotline. An increase in the EMS call volume for 1813 calls (excluding the coronavirus hotline) from the first confirmed case in Denmark on February 27, 2020, until one month later March 27, 2020, was not observed compared to the same period in 2019.
The EMS 112 emergency line received 8,870 calls in 2020 compared to 8,494 in 2019, and the 1813 medical helpline received 84,317 in 2020 compared to 84,176 in 2019 (Table 1) from February 26 until one month after. There was a difference in the age of the callers (a mean of 53.0 years in 2020 and a mean of 53.6 years in 2019). Similarly, minor but not clinically relevant differences can be observed for the 1813 medical helpline (Table 1). There was no apparent difference in the relative distribution of call volume by day or day of the week (Table 1).
However, since the introduction of the coronavirus hotline on March 4, 2020, a large number of calls to the EMS were forwarded to the specific coronavirus hotline. The coronavirus hotline received a total call volume of 21,063 calls in this period (Table 1) and had mean queue times of 13 minutes and 46 seconds (Table 1).
Insert the following here: Table 1. Demographics of EMS calls from February 27 to March 27, 2020
The call volume on the coronavirus hotline peaked on March 12, with approximately 2,100 calls in one day. Furthermore, 4,409 (20.9%) of the calls to the coronavirus hotline were redirected to the EMS 1813 medical helpline; these calls were to be further assessed and triaged by a physician.
Hence, in total, a significant (P < 0.001) increase in the total EMS call volume was observed, most extensively from March 2–15 but was mitigated by the implementation of to the coronavirus hotline (Fig. 3). After day 19 (March 15), a minor decrease in total call volume was witnessed on both the 1813 medical helpline and the specific coronavirus hotline (Fig. 3).
Insert the following here: Fig. 3. Accumulated call volumes and web-based self-triage system use
EMS queue time
Although call volume is seemingly not substantially higher once the capacity is overloaded, the EMS queue time is the first marker and will rise steeply. The limited capacity of the EMS 1813 medical helpline is seen to be significantly overloaded in this period, with significantly higher queue time than in 2019. In 2020, the mean queue time was 12 minutes and 2 seconds (CI: 11:55 − 12:09), which is significantly (P < 0.001) higher than the two minutes and 23 seconds (CI: 02:22 − 02:25) observed in 2019 (Table 1). Several periods with a maximum queue time of up to 2 hours was noted in the very peak of the corona burden prior to implementation of the coronavirus hotline.
Several peaks in queue time are notable on the EMS 1813 medical helpline, most notably on March 1, 8–9, 11–12 and 15 (Day 4, 11–12, 14 − 5 and18 in Fig. 4). The calls forwarded to the coronavirus hotline had a similar peak pattern after the implementation, except for the initial peak on March 1 prior to implementation (Fig. 4). The increase in queue time is due to not only an increase in call volume but also an increase in time for call handling (conversations are longer by approximately 1 minute).
Several events coincide with peaks in queue time, notably a slow peak in queue time in the days after the announcement of the first confirmed patient (see Fig. 4).
Insert the following here: Fig. 4. Queues for EMS lines and key events around the Danish COVID-19 impact
Use of the WBSTS
The WBSTS was implemented on March 15 and was included on the Copenhagen EMS webpage. In the first month, the WBSTS was used 107,894 times. A total of 92.2% of users completed all questions on the WBSTS, and 14.6% marked that they had respiratory distress (Table 2).
A total of 24,883 users provided information and feedback for the system. Among the users agreeing to provide feedback, 80% found the system satisfactory, and 20% did not. The median age for users was 42 (IQR 31–54), with more female users (59%). The WBSTS had more users in the daytime than at night. Of the three possible types of advice that could be offered, the WBSTS advised 24.0% (21,186 calls) of users that they had reported symptoms of COVID-19, 35.3% (31,1-1-2 calls) of users were advised to self-isolate, and 40.7% (35,956 calls) were advised to call the EMS and coronavirus hotline. No correlation between EMS call volume and use of the WBSTS could be documented.
Insert the following here: Table 2. Demographics of web-based self-triage system users