A medical expert leading a study on mixing Covid-19 vaccines in Hong Kong will look into a rare case of a 32-year-old man in the city who had received three shots of two different coronavirus drugs.
Professor Ivan Hung Fan-ngai from the University of Hong Kong, who is also co-convenor of the government panel on vaccine effects, said his team would meet the man this week at Queen Mary Hospital to conduct tests.
“It is on the request of the Department of Health that we follow up on the case. It is not part of our research,” Hung said. “Basically, we will do some blood tests and check his antibody levels. If he does not show adverse reactions, then, there should not be any major problem for now. But longer term observation would still be needed before any conclusion can be reached.”
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Health officials reported on Sunday that the man had received three vaccine doses. He was given a first shot of the German-made BioNTech vaccine at a community centre on March 12. He then went to a private clinic on March 28 and received a Chinese-made Sinovac shot, without disclosing his previous BioNTech jab.
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The private doctor reported the man after checking the patient’s electronic vaccination record, but only after the Sinovac jab had been administered. The doctor told him not to receive another dose of Covid-19 vaccine but he went ahead two weeks later with a third jab – this time BioNTech – and did not tell staff at the centre about his vaccination history.
A Department of Health spokesman said on Monday that it had not received any report of adverse events related to the case.
Hung advised against mixing vaccines, saying this could involve “risk”. “There were news reports earlier indicating some countries could try mixing vaccines to overcome supply bottlenecks. But we have not heard of published results of the efficacy,” the professor said.
He stressed: “Two shots of Sinovac or BioNTech are already good enough.”
Hung, from HKU’s department of medicine, is leading a year-long clinical research on Sinovac and BioNTech vaccines to see if mixing both would yield better protection than two shots from either type.
More than 100 volunteers are being recruited for trials.
Sinovac and BioNTech vaccines work differently – the first uses an inactive virus while the latter is based on the mRNA molecule – to stimulate the immune system into generating antibodies.
Hung said the 32-year-old man in question would not be part of the research. “Getting mixed vaccines arbitrarily is not the same as taking different vaccines under our clinical study. We follow a set of procedures and participants will only get two shots.”
Meanwhile, a 54-year-old man, who got his first Sinovac jab on April 2, died on Sunday, but there has been no established link to the vaccine as yet. The Department of Health said the man was a smoker and received his jab at Yuen Wo Road Sports Centre in Sha Tin.
“There was no record that the man complained of feeling unwell during observation at the vaccination centre,” the department said in a statement.
The man was found unconscious in his home on Sunday and was sent to North District Hospital where he later died.
“So far, there is no clinical evidence to indicate his death was caused by the vaccine,” the department added. It also said it would refer the case to Hung’s panel for a causality assessment.
There have been 17 deaths recorded involving people who had been vaccinated. None of the cases – mostly centred on the elderly or those with chronic illnesses – have been linked to vaccines as yet.
As of 8pm on Monday, 1,123,500 doses of Covid-19 vaccines have been administered in Hong Kong. According to the government, 741,332 people have received their first dose, or 9.9 per cent of the city’s population, comprising 380,542 taking the Sinovac jabs and 360,790 getting the BioNTech shots.
Of the 382,168 people receiving their second dose, or 5.1 per cent of the population, 233,339 were Sinovac jab recipients and 148,829 took the BioNTech version.
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