Myocarditis and Pericarditis following COVID-19 Vaccination in Thailand

Abstract

Background: Myocarditis and pericarditis cases following Coronavirus 2019 (COVID-19) vaccination were reported worldwide. In Thailand, COVID-19 vaccines were approved for emergency use. Adverse event following immunization (AEFI) surveillance has been strengthened to ensure the safety of the vaccines. This study aimed to describe the characteristics of myocarditis and pericarditis, and identify the factors associated with myocarditis and pericarditis following COVID-19 vaccination in Thailand. Method: We carried out a descriptive study of reports of myocarditis and pericarditis to Thailand’s National AEFI Program (AEFI-DDC) between 1 March and 31 December 2021. An unpaired case–control study was conducted to determine the factors associated with myocarditis and pericarditis after the CoronaVac, ChAdOx1-nCoV, BBIBP-CorV, BNT162b2, and mRNA-1273 vaccines. The cases consisted of COVID-19 vaccine recipients who met the definition of confirmed, probable, or suspected cases of myocarditis or pericarditis within 30 days of vaccination. The controls were people who underwent COVID-19 vaccination between 1 March and 31 December 2021, with no adverse reactions documented after vaccination. Results: Among the 31,125 events recorded in the AEFI-DDC after 104.63 million vaccinations, 204 cases of myocarditis and pericarditis were identified. The majority of them were male (69%). The median age was 15 years (interquartile range (IQR): 13–17). The incidence was highest following the BNT162b2 vaccination (0.97 cases per 100,000 doses administered). Ten deaths were reported in this study; no deaths were reported among children who received the mRNA vaccine. Compared with the age-specific incidence of myocarditis and pericarditis in Thailand before the introduction of the COVID-19 vaccination, the incidence of myocarditis and pericarditis after the BNT162b2 vaccine was greater in the 12–17 and 18–20 age groups in both males and females. It was higher after the second dose in 12- to 17-year-olds (2.68 cases per 100,000 doses administered) and highest after the second dose in male 12- to 17-year-olds (4.43 cases per 100,000 doses administered). Young age and a mRNA-based vaccination were associated with myocarditis and pericarditis following administration of the COVID-19 vaccine after multivariate analysis. Conclusions: Myocarditis and pericarditis following vaccination against COVID-19 were uncommon and mild, and were most likely to affect male adolescents. The COVID-19 vaccine offers the recipients enormous benefits. The balance between the risks and advantages of the vaccine and consistent monitoring of AEFI are essential for management of the disease and identification of AEFI.

Sex Differences in Serious Adverse Events Reported Following Booster Doses of COVID-19 Vaccination in Thailand: A Countrywide Nested Unmatched Case-Control Study

“…Regardless of serious outcomes, most studies reported the opposite trend: females have a higher risk than males, and younger adults have a higher risk than older adults [ 3 , 4 , 5 , 6 , 7 , 8 ]. For SAE after the primary doses, some conditions dominated in younger individuals, such as myopericarditis [ 30 , 31 , 32 ] and anaphylaxis [ 4 , 28 ], which was similarly found in this study after booster doses. This study further evaluated the risk of all SAE, in which half of the cases were cardiovascular events (other than myopericarditis) and thrombotic events.…”

“…On the other hand, the risk of SAE following a booster dose in the younger males could be underestimated due to rare younger males receiving a booster dose. Compared to a countrywide study that used the same databases of primary doses, there was a larger study population of young males that made it possible to capture 137 cases of myocarditis and pericarditis and report the highest risk in young males [ 30 ]. The symptoms of myopericarditis in the young were mild, and they recovered without permanent heart damage [ 30 , 31 , 32 ].…”

“…Compared to a countrywide study that used the same databases of primary doses, there was a larger study population of young males that made it possible to capture 137 cases of myocarditis and pericarditis and report the highest risk in young males [ 30 ]. The symptoms of myopericarditis in the young were mild, and they recovered without permanent heart damage [ 30 , 31 , 32 ]. Therefore, the staff reporting AEFI-DDC surveillance system that was designed to capture SAE could have missed these cases.…”

Incidence and Nature of Short-Term Adverse Events following COVID-19 Second Boosters: Insights from Taiwan’s Universal Vaccination Strategy

“…These reports significantly impact public willingness to receive vaccinations, consequently affecting vaccination rates [ 7 , 19 , 20 ]. Of particular concern are the severe adverse events associated with booster vaccines, such as vaccine-induced myocarditis and pericarditis, multisystem inflammatory syndrome in children (MIS-C), and multisystem inflammatory syndrome in adults (MIS-A) [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. The question of whether the incidence and severity of side effects increase with additional doses is of utmost importance and urgently requires detailed clinical reports to understand the current situation [ 28 ].…”