HONG KONG — Recipients of the BioNTech Covid-19 vaccine should get their jabs on the thigh rather than arm to reduce heart inflammation risks, Hong Kong health experts have said, after a panel delivered its first “indeterminate” ruling on whether a death was linked to the shot.

Advisers to the city’s pandemic strategy said on Thursday (Dec 9) that changing the injection site would make the German-made jab safer for all age groups, with one urging the government to make it standard practice for adolescents.

The renewed calls emerged following a statement from the Department of Health on the death of a 66-year-old woman 16 days after receiving the BioNTech vaccine. A post-mortem found that she had suffered from myocarditis, an inflammation of the heart muscle.

“The causal relationship of that case with vaccination has been concluded to be indeterminate,” health authorities said in a separate press release, but added that “no unusual pattern” following the vaccination had so far been identified.

The authorities said more details of the case — as reviewed by the Expert Committee on Clinical Events Assessment Following Covid-19 Immunisation — would be disclosed on Friday when the department published its latest safety monitoring report on coronavirus vaccinations.

The expert committee has so far reviewed 49 deaths, all recorded within 14 days of Covid-19 vaccination. None of the fatalities were found to be related to the jabs, while another was still awaiting further information before final assessment.

Professor Ivan Hung Fan-ngai, co-convenor of the committee, told the Post that the panel could not rule out that the 66-year-old woman might have suffered from vaccine-related myocarditis. He added her condition might also be related to parvovirus, another viral infection that could lead to the same heart problems.

Prof Hung said that to prevent vaccination-induced myocarditis, the jab should be administered into the thigh instead of the arm, for people of all ages.

“[The injection site] is further away from the heart, and [the vaccine content] has to pass through the inguinal lymphatics. Few vaccine antigens could reach the heart,” he said.

Government pandemic adviser Professor Yuen Kwok-yung agreed that thigh injections were the safest option for all age categories taking the BioNTech jab, adding it was particularly important for teenagers.

“Thigh injections for adolescents receiving the BioNTech vaccine should be made policy,” Prof Yuen said, warning that the age group carried the highest risk of developing myocarditis following BioNTech vaccination.

The city has so far recorded 83 myocarditis cases following the jab, including 34 adolescents aged 12 to 15.

He suggested other age groups could be given the option of whether to receive the jab in the arm or thigh.

Prof Yuen first proposed the change of injection method to the government a few months ago. He pointed out previously that while thigh jabs could reduce certain risks, they might be an inconvenience as recipients would have to wear shorts, skirts or loose trousers.

In September, the joint scientific committee under the Centre for Health Protection, which advises the government on vaccination strategy, recommended the option of thigh injection “as a precautionary principle”.

It cited studies stating that such injections could “minimise the potential side effects of the vaccine”, although the recommendation was focused mainly on children and adolescents.

Younger people were also advised to take just one dose of the BioNTech vaccine instead of the standard two shots to reduce the chance of heart inflammation. That was issued in the wake of overseas and local data showing adolescents to be at risk of myocarditis and pericarditis after inoculation, generally after the second dose.

Family doctor Edmund Lam Wing-wo said community vaccination centres would need to adapt given that needles for thigh injections were slightly longer than those used for arms.

He also suggested that staff at centres should remind recipients that an injection to the upper leg was an option, with members of the public already able to request one.

Dr Marco Ho Hok-kung, deputy chief medical executive at Virtus Medical, said administering thigh vaccinations would not be a major issue.

The company began offering BioNTech jabs on Monday under a pilot scheme for private healthcare institutions.

“If someone requests a [vaccination on the thigh], a physical assessment will be done to see whether that person is overweight or obese,” Ho said, noting that longer needles would be needed for people in that category. SOUTH CHINA MORNING POST