Table. Calculated attack rates for identified coronavirus disease outbreak cases among staff members and guests attending events in a nightclub, Berlin, Germany, March 2020*.
| Characteristics | Cases, no. (%) | No. attending |
||
|---|---|---|---|---|
| Event 1 | Event 2 | Event 3 | ||
| Estimated guests† | – | 300 | 150 | 200 |
| Staff members, n = 16‡ |
– |
11 |
6 |
11 |
| Total cases |
74 (100) |
|
|
|
| Cases by generation§ | ||||
| First-generation, n = 55 | 55 (74.3) | |||
| Guests¶ | 46 (83.6) | 39 | 0 | 3 |
| Staff | 9 (16.4) | – | – | – |
| Second-generation, n = 10 | 10 (13.5) | – | – | – |
| Generation unknown, n = 9 |
9 (12.2) |
– |
– |
– |
| Cases by case definition# | ||||
| Confirmed cases, n = 72 | 72 (97.3) | – | – | – |
| PCR-confirmed | 70 (97.2) | – | – | – |
| Antibody testing-confirmed | 2 (2.8) | – | – | – |
| Probable cases |
2 (2.7) |
– |
– |
– |
| Attack rate, %** | Pooled over all events | Event 1 | Event 2 | Event 3 |
| Guests | – | 13 | – | 2 |
| Staff | 56 | – | – | – |
*Event-related case numbers are shown only for first-generation guest cases as all of them confirmed to only have attended 1 of the 3 events. –, value not calculated. †The exact number of guests attending the events is unknown. For event 1, an estimate of attending guests was based on the maximum capacity of the club; staff and contacted guests confirmed that the club was running at full capacity. For events 2 and 3, the club owner provided estimates listed here. ‡Most staff members attended >2 of the events. §First-generation cases were defined as cases exposed during event 1, 2, or 3. Second-generation cases were defined as cases without exposure at club X but with exposure to first-generation cases. Cases of unknown generation were confirmed cases of the outbreak but without contact information to reveal whether they were first- or second-generation cases. ¶All guests contacted confirmed they attended only 1 of the 3 events. Information on the event of exposure was available for 42 first-generation cases among guests. No guest case reported visiting club X for event 2. #The outbreak case definition is described in the Appendix. All cases confirmed by antibody testing were otherwise probable cases. **Calculation of primary attack rates for guests was based on approximations for the denominator, the number of guests attending. Because most staff members were exposed repeatedly while working at >1 event we separately calculated attack rates for staff pooled over all events.