​In response to media enquiries, the Department of Health (DH) said today (July 20) that up to July 19, 2021, around 63 000 doses of Comirnaty vaccines have been administered to adolescents aged 12 to 15. In the same period, the DH had received from the Hospital Authority (HA) a total of three reports of suspected myocarditis for adolescents in the same age group following Comirnaty vaccination.
According to the information provided by HA, the three cases involved one 12-year-old and two 15-year-old males. They complained of chest pain about two days after receiving the second dose of Comirnaty vaccine. They were all admitted to HA's hospitals for monitoring and treatment, and their conditions were stable. These cases would be passed to the Expert Committee on Clinical Events Assessment Following COVID-19 Immunization (Expert Committee) for conducting causality assessment.
Myocarditis and pericarditis refers to inflammation of the heart muscle and inflammation of the tissue surrounding the heart respectively. Most affected cases respond well to treatment and can usually return to normal daily activities after their symptoms improved. Adolescents and young adults should avoid strenuous exercise for one week after Comirnaty vaccination. They should seek immediate medical attention if they develop symptoms indicative of myocarditis or pericarditis such as acute and persisting chest pain, shortness of breath, or palpitations following vaccination.
The Expert Committee noted that there were reports from overseas drug regulatory authorities about cases of myocarditis and pericarditis following vaccination of Comirnaty, especially among younger vaccine recipients. On July 5, the Expert Committee endorsed the inclusion of myocarditis and pericarditis in the list of serious or unexpected Adverse Events Following Immunisation to enhance monitoring. The DH has also been closely monitoring adverse events of myocarditis or pericarditis among adolescents of 12 to 15 years old.
According to the manufacturer of Comirnaty, cases of myocarditis and pericarditis have primarily occurred within 14 days following vaccination, more often after the second vaccination, and more often in younger men. Based on these reports, the supplier of Comirnaty has also updated the product's package insert to include myocarditis and pericarditis as its adverse reactions. The latest package insert of Comirnaty is available at the website of Food and Health Bureau (www.fhb.gov.hk/download/our_work/health/201200/e_SmPC_for_HK.pdf).
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