The government’s Novel Coronavirus Response and Coordination Centre announced in a statement yesterday that two male Macau residents who returned to Macau from Tokyo last month have tested positive for the novel coronavirus in their antibody tests, also known as serology tests.
However, the Health Bureau (SSM) has decided not to classify the two men as confirmed COVID-19 patients “for the time being”, the statement said.
The two males have not come down with any symptoms.
The Health Bureau has concluded that it is likely that the first man had previously been infected elsewhere with the novel coronavirus without any symptoms before his return to Macau, while the bureau will still have to establish whether the second man was infected elsewhere with the virus a short time or some time ago before his return to Macau.
A total of 109 Macau residents who departed from 14 countries returned to Macau onboard two Air Macau flights from Tokyo on January 21, one of whom was confirmed as Macau’s 47th COVID-19 patient the next day. The patient is a 43-year-old woman who had departed from Dubai to Tokyo via Singapore on January 19. The patient is still undergoing treatment in the isolation ward of the public Conde de São Januário Hospital Centre.
Eight passengers who were sitting near the woman (the 47th COVID-19 patient) on the plane – because of which they were classified as having been in close contact with the woman – were taken to the Health Bureau’s Public Health Clinical Centre in Coloane for 21 days of quarantine and medical observation, while the other 100 passengers and 16 crew members on the two flights were taken to Grand Coloane Resort near Hac Sa Beach for 21 days of quarantine and medical observation.
The passengers and crew members underwent their first nucleic acid test (NAT) upon arrival at the local airport, after which they have to undergo three other nucleic acid tests during the 21-day quarantine period – carried out on the fifth, 12th and 20th days of the quarantine period.
The statement noted that the Macau residents had stayed in countries where the COVID-19 epidemics are serious and highly contagious strains of the novel coronavirus have been spreading before returning to Macau on the two flights from Tokyo on January 21, because of which they carry a high risk of having been infected with COVID-19 before their return to Macau.
The statement also noted that cases have been reported in many countries according to which people are only confirmed as COVID-19 cases after undergoing several nucleic acid tests.
The statement said that therefore the centre has decided to carry out two blood tests on each of the passengers who are currently undergoing their 21-day quarantine, in addition to the four required nucleic acid tests, so as to “further reduce the public health risk they would pose to their families and the community after completing their quarantine”.
According to the statement, the government carried out the first serology test on the passengers on Wednesday, while the second test will be carried out on Wednesday next week. The statement said that the blood tests “aim to confirm that they [the passengers] have not been infected with the novel coronavirus”.
IgM, IgG antibodies
The statement pointed out that normally if a person is infected with a particular infectious disease, they will develop IgM antibodies during the early stage of the disease, while they will develop IgG antibodies during the later stage of the disease when the IgM antibodies will gradually disappear.
According to the statement, two men tested positive for the novel coronavirus in their antibody tests on Wednesday. The first man, a 30-year-old Portuguese national, tested negative for immunoglobulin M (IgM) antibodies but positive for immunoglobulin G (IgG) antibodies. The statement said that as he has tested negative for COVID-19 for the third time in nucleic acid tests within the past 14 days and has not come down with any symptoms, the Health Bureau has concluded that it is likely that he had previously been infected with the novel coronavirus elsewhere before his return to Macau.
However, the statement said that for safety reasons, the 30-year-old man, who returned to Macau from Portugal, has been transferred from the quarantine facilities to the public hospital’s isolation ward for a CT scan, further observation and follow-up nucleic acid testing.
However, the other man, a 43-year-old local Chinese, tested positive for IgM antibodies and negative for IgG antibodies, the statement said, adding that the man, who returned to Macau from Switzerland, has tested negative for COVID-19 for the third time in nucleic acid tests within the past 14 days and has not come down with any symptoms.
The statement said that if the 43-year-old man tests positive for COVID-19 in another nucleic acid test later, this means that he is in the early stage of the novel coronavirus disease. The statement said that if the man tests negative for COVID-19 in another nucleic acid test later, this means that he is recovering from the disease.
According to the statement, the Health Bureau has also transferred the 43-year-old man, who works as a chef, from the quarantine hotel to the public hospital’s isolation ward for a CT scan, further observation and follow-up nucleic acid testing.
The statement said that the Health Bureau has decided not to classify the two men as confirmed COVID-19 patients “for the time being”.
Local returnees wearing protective suits queue for COVID-19 tests after disembarking from an Air Macau plane at the local airport on January 21. Photo: GCS
