In mid-July 2021, a group of teenagers developed acute myocarditis and pericarditis after receiving the Fupitech vaccine in Hong Kong. The Department of Child and Adolescent Sciences, the Department of Pharmacology and Pharmacy and the Department of Internal Medicine of the University of Hong Kong's Li Ka Shing School of Medicine (HKU) immediately launched a research survey. On January 25, the Faculty of Medicine of HKU held an online press conference to announce that the results of the study showed that due to the 7-fold difference in the risk of myocarditis between the first and second doses of the fupiter vaccine, only one dose of fupiter can effectively reduce the risk. HKU School of Medicine emphasizes that adolescents receiving the second dose of FuBTech should be at least three months apart from the first dose to reduce the chance of myocarditis. Given the potential threat of the Omicron variant virus, HKU Medical School recommends that adolescents aged 12 years or older receive their first dose of COVID-19 vaccine as soon as possible.
Studies show that as of 18 October 2021, 43 of the 224,560 vaccinated adolescents were hospitalized for myocarditis after receiving the Fuobide vaccine, of which 36 occurred after the second dose of the vaccine (22.15 per 100,000 people) and the rest after the first dose (3.12 per 100,000 people). If the first dose is given three weeks after the first dose of fumixidine, the relative risk after the second dose is estimated to be 7.11 times that of the first dose. Following the announcement of the recommendation that adolescents receive only the first dose of Fupiter, 40,167 adolescents have suspended the second dose of the vaccine, which is estimated to have prevented about 9 cases of myocarditis.
The study also pointed out that between 14 June and 4 September 2021, a total of 178163 people aged 12-17 in Hong Kong (49.59% of whom were women, i.e. 88,357 people) received 305406 dose of the Fupiter vaccine. Acute myocarditis or pericarditis developed after vaccination in 33 adolescents, including 29 males (87.88%) and 4 females (12.12%) with a median age of 15.25 years. The majority (27 cases, or 81.82%) of cases of acute myocarditis or pericarditis after vaccination, after receiving the second dose, compared with only 6 cases after the first dose. The median time for these patients to develop acute myocarditis or pericarditis after receiving the second dose of the vaccine is two days. Symptoms were mild in all patients.
Another controlled study involved adolescents and adults aged 12 or above in Hong Kong. According to the data, as of 2 August 2021, a total of 2291444 doses of Kerraf (Kexing) and 3496629 dose of Fubitech were injected in Hong Kong, with a total of 160 cases of myocarditis or pericarditis. The incidence of myocarditis or pericarditis is estimated to be 0.31 and 0.57 per 100,000 doses of kerrib and fubritide, respectively. Compared with hospital controls, the risk of myocarditis or pericarditis (Odds Ratio = 3.57) was found to be about three times higher than that of unvaccinated individuals. This risk is mainly related to the second dose of fupiter. There are no data showing a significant association between Kerrafur and myocarditis or pericarditis. Dr Ip Pak Keung, Clinical Associate Professor in the Department of Child and Adolescent Sciences, Li Ka Shing Medical College, The University of Hong Kong, said: "According to preliminary data from other countries, the longer the interval between the second dose and the first dose of vaccine for adolescents, the lower the risk of myocarditis. ”
Shenzhen Satellite TV's direct news reporter in Hong Kong asked: "Since there is no data showing that There is a significant association between Kerraffle (Kexing) and myocarditis or pericarditis, does the HKU School of Medicine encourage adolescents to choose to take the Kexing vaccine?" Facilitates second and reinforcement shots as soon as possible. ”
In response, Professor Wong Chi Kee, Head of the Department of Pharmacology and Pharmacy, Li Ka Shing Medical College, The University of Hong Kong, said: "The current data on this comparative study are all adults, and there is no data on children. Regarding the sequelae of myocarditis, the relevant data of Kexing shows that there are no adults, and the relevant data of Fubitai shows that adults have it, and accurate research must wait for the data of children. Parents and young people have choices about which vaccines to administer. Professor Huang Zhiji stressed that if the children want to retake Bitai, the second injection will have to wait for more than 3 months to be shot.
Dr Ip Pak Keung, clinical associate professor in the Department of Child and Adolescent Sciences at the University of Hong Kong's Li Ka Shing School of Medicine, added that more than 100 million Koxing vaccines have been administered in adolescents such as Chinese mainland and Southeast Asian countries, with high safety and no side effects such as myocarditis. If parents are concerned about one vaccine, they can choose another.
