Experts suggest ways to reduce side effects of Covid-19 vaccine
Some Hong Kong scientists say people vaccinated with the BioNTech vaccine should get the shot in the thigh, not the upper arm, to reduce the risk of myocarditis.
Advisers to Hong Kong's anti-pandemic strategy say changing the injection site will helpVaccineBioNTech is safer for all age groups, including adolescents.
The call comes after Hong Kong health authorities reported that a 66-year-old woman died 16 days after receiving the BioNTech vaccine. An autopsy found she had myocarditis.
However, the health authority said: “It is not possible to determine whether there is a link between that case and vaccination.”
The Expert Committee for the Assessment of Clinical Events Following Covid-19 Vaccination reviewed 49 deaths within 14 days of vaccination. None of the deaths were determined to be related to vaccination.
The committee could not rule out the possibility that the 66-year-old woman had myocarditis linked to the vaccine, Professor Ivan Hung Fan-ngai said, adding that the patient's condition could also be linked to another viral infection called parvo, which can cause heart problems.
 |
| Illustration: UL |
Professor Hung said that to prevent myocarditis caused by vaccination, people should be injected into the thigh instead of the arm.
“The injection site is further from the heart, so the vaccine content has to travel through the lymphatic system in the groin. Very little of the vaccine antigen can reach the heart,” the professor said.
Professor Yuen Kwok-yung also agreed that intramuscular injection is the safest option for all ages to use the BioNTech vaccine, especially important for teenagers.
“It should be standard practice to give injections in the thigh to adolescents,” said Professor Yuen, who warned that this was the age group most at risk of myocarditis after vaccination.
The expert suggests other age groups can choose to get the shot in the arm or thigh.
Professor Yuen first proposed the change to the injection method a few months ago. He previously pointed out that while injecting into the thigh could reduce some risks, it was inconvenient because people would have to wear shorts, skirts or loose pants.
In September, the Scientific Committee of the Center for Health Protection recommended the thigh injection option.
The agency cited studies that said such shots could “minimize potential side effects of the vaccine,” recommending a focus on children and adolescents.
 |
| Covid-19 vaccination for high school students. Photo courtesy of Duc Anh |
Younger people are also advised to get just one dose of the Covid-19 vaccine instead of the standard two.
Family doctor Edmund Lam Wing-wo said it will take longer for community vaccination centres to adapt to administering shots in the thigh compared to administering shots in the arm.
Dr. Marco Ho Hok-kung, deputy chief medical officer at Virtus Medical, said that vaccination in the thigh should not pose too many difficulties.
“If someone requests a thigh injection, a physical assessment will be done to see if they are overweight or obese,” Dr. Ho said, noting that those in that group will need a longer needle.