Diamond
Princess COVID-19 Cases
From National
Institute of Infectious Disease Japan
Dear Colleague
I am enclosing the NIID report sent to me
by our Japan CMAAO colleague Marie Urabe. Great work being done.
Dr KK Aggarwal
President CMAAO
NIID Excerpts:
1. A cruise ship, Diamond
Princess, had travel that originated in Yokohama on 20 January and included
stops in Japan (Kagoshima), Hong Kong, Vietnam, Taiwan and Japan (Okinawa),
before arriving back in Yokohama on 3 February.
2. A passenger who disembarked on 25 January in
Hong Kong, has presented with cough since 19 Jan and was confirmed positive for
Novel coronavirus on 1 February.
3. The Japanese government requested that the
Diamond Princess stay at port, with no passengers or crew disembarking, in
Yokohama when it arrived on 3 February.
4. During 3-4 February, health status of all
passengers and crew members were checked by questionnaire by quarantine
officers, and respiratory specimens were taken from symptomatic passengers,
crew, and their close contacts to test for Novel coronavirus.
5. On 5 February, a lab-confirmed case of
COVID-19 led to the quarantine of the Diamond Princess for 14 days beginning at
7am, with passengers requested to stay in their cabins. As of 5 February, there
was a total of 3711 individuals on board the Diamond Princess, with 2666
passengers and 1045 crew members.
Quarantine Measures:
1. 5th Feb:
Crew members were provided with personal protective equipment (PPE) and
instructed on appropriate IPC practices.
2. 7th Feb:
Passengers were provided thermometers for self-monitoring of body temperature,
with instructions on calling a “Fever Call Center”, if they had a fever above
37.5C.
3. Passengers who
developed fever were referred to the medical team in charge and were tested for
Novel coronavirus.
4. Passengers who
developed serious illness, including non-COVID-19 morbidities, were referred
the ship’s Medical Center, which provided essential health services.
5. Those passengers
with lab-confirmed COVID-19 were disembarked and transferred to an isolation
ward at healthcare facilities.
6. Their cabinmates
were defined as “close contacts” and were therefore tested. If positive, they
were also confirmed as a case and disembarked to a healthcare facility.
7. If they tested
negative, they remained on board but with a 14-day quarantine period reset
after the last contact with the confirmed case.
8. All crew and
healthcare staff onboard the Diamond Princess were instructed to follow
international guidance on infection prevention and control.
9. To maintain
operations of the ship, some crew continued to perform essential, limited
services while the ship remained in quarantine.
10. This led to those
crew members not remaining fully isolated, in the same manner as passengers, during
the quarantine period.
Data Collection:
1. Initially, only
symptomatic cases and close contacts were being tested for COVID-19.
2. 11 February: due to
the expansion of laboratory capacity, with quarantine officers systematically
collecting respiratory specimens from all passengers by age group, starting
with those 80 years old and older as well as individuals with co-morbidities,
such as diabetes or a heart condition.
3. Respiratory
specimens collected were tested via PCR for confirmation of Novel coronavirus.
4. Epidemiological
data collected was initially limited due to the emergency nature of the
quarantine and included data on onset of symptoms, date of lab confirmation,
and close contacts.
5. A confirmed case of COVID-19, for this report,
is anyone, passenger or crew, who had a positive PCR test for Novel
coronavirus, independent of their symptom presentation. In most cases, the “population
on board,” refers to the 3,711 passenger and crew aboard Diamond Princess on 5
February.
Preliminary Results:
1. As of 18 February,
there have been 531 confirmed cases (14.3% of all individuals on board on 5
February), including 65 crew and 466 passengers.
2. A total 2404
respiratory specimens were tested, and 542 were positive (22.5), including
double tests.
3. Among confirmed
COVID-19 cases with recorded symptom onset (n=184), there were 33 (18%) with
onset dates before 6 February, which was the first full day of quarantine, and
151 (82%) with onset dates on or after the 6th.
4. A total 255 (48%)
of the confirmed cases were asymptomatic when the respiratory specimen was
collected.
5. Of these, 8 were
crew and 247 were passengers. (Information on development of symptoms after
disembarkation of asymptomatic confirmed cases is not currently available.)
6. A total 23
passengers with reported onset dates were confirmed after another passenger in
the same cabin had been confirmed.
7. From 13 February to
now, 81% of cases among confirmed passengers or crew with reported onset dates
(n=22) occurred in crew (n=13) or passengers from cabins with a previously
confirmed case (n=5).
Preliminary Conclusions:
1. Based on the number
of confirmed cases by onset date, there is clear evidence that substantial
transmission of COVID-19 had been occurring prior to implementation of
quarantine on the Diamond Princess on 5 February (see also febrile patient
visits to the on-board clinic below).
2. The decline in the
number of confirmed cases, based on reported onset dates, implies that the
quarantine intervention was effective in reducing transmission among
passengers.
3. Transmission toward
the end of the quarantine period, which is scheduled to end for most passengers
on 19 Feb, appears to have occurred mostly among crew or within passenger
cabins.
4. It should be noted
that due to the nature of the ship, individual isolation of all those aboard
was not possible.
5. Sharing of cabins
was necessary, and some crew had to continue to perform essential duties for
the functioning of the vessel with passengers aboard.
6. Recent
confirmations of asymptomatic cases can be explained by the systematic testing
of passengers that began around 14 Feb. Although some of these cases may have
been secondary cases within a given cabin, it is difficult to know when
transmission occurred. They may have been infected before the quarantine began.
Nevertheless, these asymptomatic cases have been disembarked and their
cabinmates have been defined as close contacts with their 14-day isolation
reset on the day the asymptomatic case was disembarked. The systematic testing
of asymptomatic cases was useful in screening these persons before allowing
them to disembark.
Preliminary Actions/Guidance:
1. Those persons
(mostly passengers) who have completed the 14-day quarantine, have not tested
positive, and pass a medical check on the 14th day, will
be disembarked on the 19th.
2. Those individuals
who were in contact with a confirmed case will be put in isolation until they
complete the 14-day period beginning after the last day of their suspected
contact with a case.
3. This includes a
large proportion of the crew members of the Diamond Princess.
4. The crew performed
essential tasks that allowed the quarantine to occur successfully for 14 days
and should be appreciated for their service.
5. As the persons aboard were exposed to a
high-risk environment for a prolonged period, all persons who disembark should
be careful about the health conditions for the time being and immediately
report to a public health center if they develop symptoms.
Percent
of persons aboard who were confirmed with COVID-19 by age group and symptom
status at the time of specimen collection.
|
Age
group
|
Symptomatic
confirmed cases (%)
|
Asymptomatic
confirmed cases (%)
|
Total
confirmed cases (%)
|
Persons
aboard on 5 February
|
|
00-09
|
0(0)
|
1(6)
|
1(6)
|
16
|
|
10-19
|
1(4)
|
1(4)
|
2(9)
|
23
|
|
20-29
|
18(5)
|
2(1)
|
20(6)
|
347
|
|
30-39
|
18(4)
|
5(1)
|
23(5)
|
429
|
|
40-49
|
18(5)
|
7(2)
|
25(8)
|
333
|
|
50-59
|
27(7)
|
22(6)
|
49(12)
|
398
|
|
60-69
|
73(8)
|
56(6)
|
129(14)
|
924
|
|
70-79
|
92(9)
|
136(13)
|
228(22)
|
1015
|
|
80-89
|
27(13)
|
25(12)
|
52(24)
|
215
|
|
90-99
|
2(18)
|
0(0)
|
2(18)
|
11
|
|
Total
|
276(7)
|
255(7)
|
531(14)
|
3711
|
Number
of confirmed COVID-19 cases with reported onset dates, by onset date, aboard
Diamond Princess, 6 – 17 February 2020 (n=151)
Febrile
Patients, by date of clinic visit, Diamond Princess clinic, 19 Jan - 2 Feb 2020
(n=79)
Characteristics
of COVID-19 Cases with reported on-set dates of 6 – 17 Feb 2020 (n=53).
|
Date
of Onset (n cases)
|
Crew
|
Passengers
|
Passengers
from cabins with another confirmed case (%)
|
|
17
Feb (0)
|
0
|
0
|
0
|
|
16
Feb (0)
|
0
|
0
|
0
|
|
15
Feb (1)
|
1
|
0
|
0
|
|
14
Feb (5)
|
4
|
1
|
1
(100%) [0]
|
|
13
Feb (16)
|
8
|
8
|
4
(50%) [2]
|
|
12 Feb (12)
|
7
|
5
|
0 (00%) [2]
|
|
11 Feb (18)
|
7
|
11
|
3 (27%) [1]
|
|
10 Feb (10)
|
3
|
7
|
3 (43%) [1]
|
|
9
Feb (24)
|
5
|
19
|
6
(32%) [9]
|
|
8
Feb (18)
|
2
|
16
|
1
(6%) [3]
|
|
7
Feb (31)
|
2
|
29
|
4
(14%) [10]
|
|
6
Feb (16)
|
1
|
15
|
1
(7%) [6]
|
|
Total
|
40
|
111
|
23
(21%) [34]
|
Note,
the number in brackets represents the number of additional confirmed cases in
the same cabin with unknown onset date.
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