Scientific Committees under CHP publish consensus interim recommendations on quarantine requirements for vaccinated close contacts of confirmed COVID-19 cases and updates interim recommendation on use of COVID-19 vaccines

     The Scientific Committee on Emerging and Zoonotic Diseases and the Scientific Committee on Vaccine Preventable Diseases (collectively the JSC) under the Centre for Health Protection of the Department of Health, joined by the Chief Executive's expert advisory panel (EAP), published today (May 7) a consensus interim recommendation on the quarantine requirements for vaccinated close contacts of locally acquired cases of coronavirus disease 2019 (COVID-19). Separately, the JSC-EAP also reviewed and updated the recommendation on COVID-19 vaccination for persons with previous COVID-19 infection.

     Following the discussion at the last meeting on April 22, the JSC-EAP has further reviewed and made recommendations based on the prevailing scientific understanding on COVID-19 and COVID-19 vaccines. The recommendations are as follows:

For close contacts of locally acquired cases who do not have the N501Y mutant strain
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     The duration of compulsory quarantine can be shortened from 14 days of quarantine in a quarantine centre (QC) to seven days of home quarantine with electronic monitoring, counting from the last day of exposure to the confirmed case (the day of last exposure is regarded as Day 0), provided the following three criteria have been satisfied:

(a) documented proof of completion of two doses of CoronaVac or BioNTech COVID-19 vaccines, and that 14 days have passed from the date of receiving the second dose#; and
(b) results of polymerase chain reaction (PCR) of the respiratory specimens taken on Day 0 or Day 1 after admission to a QC being negative; and
(c) positive immunoglobulin G (IgG) or total antibody against SARS-CoV-2 spike protein, or positive surrogate neutralising antibody, taken after admission to a QC.

     During the period of home quarantine, the close contact should have a deep throat saliva (DTS) specimen taken on Day 5 after last exposure to the confirmed case. After completing the seven-day home quarantine, the close contact will be subject to seven days of self-monitoring, and to compulsory testing at a community testing centre (CTC) on Day 12.

For close contacts of locally acquired cases detected to have the N501Y mutant strain
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     The duration of quarantine in a QC can be shortened from 21 days to 14 days after the last day of exposure plus seven days of self-monitoring, counting from the last day of exposure to the confirmed case, and they are also subject to compulsory testing at a CTC on Day 19, provided the following three criteria have been satisfied:

(a) documented proof of completion of two doses of CoronaVac or BioNTech COVID-19 vaccines, and that 14 days have passed from the date of receiving the second dose#; and
(b) results of PCR testing of the respiratory specimens taken on Day 0 or Day 1 after admission to a QC, and those taken on Day 7 and Day 12 after last exposure to the confirmed case, being all negative; and
(c) positive IgG or total antibody against SARS-CoV-2 spike protein, or positive surrogate neutralising antibody, taken after admission to a QC.

# The following persons are regarded as satisfying criteria (a):

1) close contacts who had documented past infection of COVID-19 within nine months after discharge; or
2) close contacts who had documented past infection of COVID-19 more than nine months after discharge plus one dose of CoronaVac or BioNTech COVID-19 vaccine, and for whom 14 days have passed from the date of receiving the dose.

     The JSC-EAP's updated interim recommendation on COVID-19 vaccination for persons with previous COVID-19 infection, which supersedes the previous consensus interim recommendation, is as follows:

     Previous COVID-19 infection usually confers immunity for at least six to nine months for the majority of patients. There is accumulating evidence showing that those previously infected with COVID-19 would be further protected by one dose of an mRNA vaccine. After receiving one dose of an mRNA vaccine, these persons may experience more systemic side effects (such as fatigue, headache, chills, muscle pain, fever and joint pain) when compared to those without previous infection. People who wish to receive an mRNA vaccine should wait for at least 90 days after discharge from previous infection. In accordance with the technical guideline issued by the National Health Commission of the People's Republic of China on March 29, 2021, people with previous COVID-19 infection can receive one dose of an inactivated COVID-19 vaccine six months after infection.

     Details of the interim recommendation are available at the CHP website (www.chp.gov.hk/en/static/24008.html).