(18 April 2003)
As at 17 April, a total of 1,297 patients have been admitted to public hospitals with Severe Acute Respiratory Syndrome (SARS). Of these, 307 (23.7%) are health care workers or medical students while 990 (76.3%) are patients, family members or visitors/contacts. A total of 272 patients (20.3%) have recovered and been discharged from public hospitals, of whom 15 were discharged on 17 April. There are 65 fatal cases.
2. A cluster of suspected SARS cases related to Koway Court, Chai Wan was first reported to the Department of Health (DH) on 9 April. Up to 17 April, there were 12 confirmed SARS cases in which 10 were residents from two blocks of Koway Court and 2 were working in Koway shopping mall. These cases included 6 males and 6 females, with age ranged between 4 and 72. The date of onset of the first case was traced back to 25 March. The onset dates for the other confirmed cases were between 3 and 12 April. Extensive epidemiological and environmental investigations are being conducted to contain the spread of the disease. Preliminary findings show that this cluster is not similar to Amoy Gardens in terms of magnitude and case pattern. The situation is being closely monitored.
Contact Tracing Exercise
3. When a passenger who has travelled on board recently is confirmed to have SARS, DH will initiate a contact tracing exercise to prevent further spreading of the disease. Between 25 March and 10 April, DH has initiated such exercise on a total of 14 flights, and as at 15 April, 545 passengers and crew members from these flights were successfully contacted. Of these, 15 passengers involving 3 flights were confirmed to have SARS and 12 of them were members of tour groups. On 16 April, another contact tracing exercise was initiated for flight CA117.
4. The Airport Authority was notified of the situation and all concerned flights arrived and departed from Hong Kong were cleaned and disinfected.
Investigation Report on the Outbreak of SARS at Amoy Gardens
5. As of 15 April, there were a total of 321 SARS cases in Amoy Gardens. There was an obvious concentration of cases in Block E, accounting for 41% of the cumulative total. The rest of the cases (59%) were scattered in 14 other blocks. In terms of onset dates, the outbreak reached its peak on 24 March and declined steadily afterwards. Block E cases appeared earlier in the outbreak and showed a point-source type of distribution. Cases in other blocks which appeared 3 days later were more evenly spread out in time.
6, In order to identify the cause of the outbreak of SARS at Amoy Gardens, the Government has conducted a detailed investigation covering epidemiological, environmental, public hygiene, building design and utilities considerations. The major findings of the investigation were announced on 17 April.
7. In gist, the findings showed that not one single factor could account for the outbreak in Block E of Amoy Gardens and that the outbreak was likely to be the result of a combination of factors, including: -
8. The report found it probable that the index patient suffering from chronic renal failure had infected a group of residents in Block E and subsequently other residents in the same block through the sewage system, person-to-person contact and the use of communal facilities such as lifts and staircases.
9. Observations from some research studies report that some people with compromised immune systems can excrete copious amount of viruses. The report also noted a swab sample taken from the toilet of an infected resident had shown positive in the test for the coronavirus!& genetic material.
10. Like other blocks in Amoy Gardens, Block E has 33 floors with 8 apartment units on each floor. Eight vertical soil stacks of each block extend along the height of the building for each of the 8 units. Each soil stack collects effluent from the water closets, the basins, the bathtubs and the floor drains of the toilets of all the units that it serves. Each of these sanitary fixtures is fitted with a U-shaped water trap to prevent foul smell and insects in the sewers from entering the toilets.
11. For the U-trap to function properly, it must be charged with water. However, the investigation found that the U-traps of the floor drains were dried up in many cases because most households had the habit of cleaning the bathroom floor by mopping instead of flushing it with water. Indeed, in tests carried out in one of the Block E units, reflux of air from the soil stack into the bathroom through the floor drain was demonstrated when the exhaust fan in the bathroom was switched on. It is postulated that the reflux could have contained droplets of contaminated sewage present in the soil stack, be dispersed into the bathroom, and be extracted by the bathroom exhaust fan into the light well between adjacent units. The contaminated droplets could then enter other units through open windows.
12. The contaminated droplets could deposit virus on various surfaces, such as the floor mat, towels and other bathroom equipment. The chance of exposure was increased given that the bathrooms in the apartment units of Amoy Gardens were generally small in size (about 3.5m2.) Records from the management office confirmed that there were numerous complaints from residents on the emission of foul gas from the floor drains indicating the likelihood of the failure of the U-traps in these apartments.
13. The report also observed that the infection had spread among close contacts, e.g. family members, although this is a smaller contributory factor to the overall outbreak.
14. Air samples, potable water samples and other environmental swabs were collected in Block E to identify the extent of contamination brought about by the infectious agent. Air and water samples showed no evidence of contamination. These laboratory test results together with the spatial and temporal distribution of cases in Amoy Gardens and the epidemiological picture argue against airborne transmission or transmission through contaminated water.
15. For more details about the investigation and the actions taken by the Government, please visit DH!&s SARS homepage (http://www.info.gov.hk/dh/ap.htm).
Measure Body Temperature of Passengers
16. With effect from April 17, all passengers departing at the Hong Kong International Airport will be required to have their body temperature taken before check-in. Any outbound passengers with a body temperature of over 38 degrees Celsius would be required to seek medical advice. Passengers who have fever or symptoms suggestive of SARS should not board a plane.
17. The first day of operation was smooth. As at 17 April, no one was suspected to have SARS among 16,149 persons departed from the airport.
18. As the check-in time may take longer, departing passengers are advised to arrive at the airport earlier. Passengers are advised to check with their carriers for lead-time required prior to flight departure. Information on measures for outbound passengers is available at the Airport Authority!&s homepage (http://www.hongkongairport.com).
19. Since 29 March, public health measures have been implemented at the airport, borders and ports to reduce imported cases. All incoming travelers are required to complete a health declaration form. Health alert cards are distributed to all passengers to heighten the awareness of the disease. As at 17 April, 758 passengers have reported sick since the implementation of these measures. Among the 14 passengers being referred to the Accident & Emergency Departments for suspected SARS, 6 were admitted to hospitals.
20. Since 10 April, the Director of Health has required all household contacts of confirmed SARS patients to confine themselves at home for monitoring and treatment up to a maximum of 10 days. The purpose is to facilitate early detection and treatment of the household contacts of SARS patients and to containing the spread of the disease in the community. As at 17 April, a total of 525 persons (from 200 households) have been affected by this requirement.
21. Implementation of the home confinement arrangement has so far been smooth. As at 17 April, DH has only issued a total of 27 warning letters. Follow-up action showed that all these defaulters have complied and stayed at home. There has not been any need for removal of SARS contacts to appointed places under this scheme.
22. Control of the spread of the SARS will only be effective through concerted efforts of the Government and the community. We recommend the public should take the following steps to help prevent contracting the disease: -
23. To empower the public in fighting against the disease, DH has also issued advices and guidelines on prevention of the SARS for various sectors. Health education information is available on the 24-hour pre-recorded hotlines (2833 0111) and has been uploaded onto DH!&s homepage (http://www.info.gov.hk/dh). A hotline (187 2222) has also been provided for public enquiries.
24. In support of the community support services rendered to vulnerable elders, DH has formulated a set of guidelines for staff of various organizations and volunteers who may visit elders in their homes. These include health messages and SARS prevention measures tailor-made for the elders. The guidelines will be disseminated to non-government organizations and can also be accessed from DH!&s Elderly Health Services homepage (http://www.elderly.gov.hk).