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CHP updates quarantine arrangements of local COVID-19 cases with mutant strain
     The Centre for Health Protection (CHP) of the Department of Health (DH) today (May 7) announced that following further analysis of epidemiological data of 11 patients of local confirmed COVID-19 cases with N501Y mutant strain, the risk of infection of their close contacts, and the testing results of the relevant compulsory testing orders and restriction-testing declarations, the CHP considers residents within the same building but not in the same unit with those confirmed cases need not be classified as close contacts and placed under quarantine for 21 days.
     People currently placed under quarantine because they reside in the same building as N501Y cases will be tested again in quarantine centre. They will be released from quarantine centre if they have obtained a negative test result but will still be subject to compulsory testing on Days 3, 7, 12 and 19 counting from the day on which the confirmed case left the relevant building. The DH will make relevant arrangements in an orderly manner according to their time of admission to the quarantine centre.
     A spokesman for the CHP said, "The CHP has all along been following up on local cases with unknown sources to identify the possible source of infection and arrange immediate quarantine for close contacts of confirmed cases to stop further transmission. Recently, several cases involving N501Y mutant strain were recorded in the community, as N501Y mutant strain carry higher transmissibility, the CHP has to handle the quarantine arrangements of these cases more prudently."
     At the same time, the CHP is also reviewing the infection control measures of confirmed cases involving mutant strain. According to the epidemiological findings so far, while case 11643 had acquired the infection during his quarantine in Ramada Hong Kong Grand in Tsim Sha Tsui, all the other 10 cases involving mutant strain were either imported (three cases) or epidemiologically linked to case 11643 (seven cases). The transmission among the epidemiologically linked cases to case 11643 is believed to have occurred among household and meal contacts. So far, available testing results of about 110 person who lived or worked in Parkes Building, where case 11643 resides in, were all negative under Day-19 testing in quarantine centre. Hence, there is no evidence suggesting transmission to other units in the same residential building rather than members of the same household.
     Extensive compulsory testing has also been imposed in the community towards places visited by the cases through the issuing of Compulsory Testing Notices, and no other cases with unknown source have been detected. As such, there is so far no evidence of other chains of silent transmissions in the community given the absence of other locally acquired N501Y cases with unknown source.
     In view of the epidemiological evidence from contact tracing for N501Y cases, the CHP considers that residents who reside in the same building as confirmed N501Y cases, other than those who reside in the same unit, would not be classified as close contacts and placed under quarantine. Instead, they would be required to have more frequent testing due to the higher transmissibility of N501Y cases and hence an increased chance of transmission by sharing common facilities in the same building. 
     For N501Y case with unknown source, a restriction-testing declaration would be made towards the building on the day when a preliminary positive or confirmation result is returned. Household contacts and people living in the same subdivided unit as the confirmed case will be subject to 21 days quarantine. Besides, all residents in the building would be subjected to compulsory testing on Days 3, 7, 12 and 19 counting from the day on which the confirmed case left the building. Moreover, in case further cases are detected in the same building, all residents of the building would be classified as close contacts and placed under quarantine for 21 days as there would be evidence of transmission.
Ends/Friday, May 7, 2021
Issued at HKT 20:30
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