Mild chest pain presents in adolescent males after Pfizer COVID-19 vaccination

Perimyocarditis has occurred in adolescent males 1–3 days following inoculation with the BNT162b2 mRNA vaccine (Pfizer-BioNTech), but all cases are mild, reports an Israel study, noting that only long-term follow-up can reveal the true impact of this transient cardiac injury.

“While it seems that the incidence of perimyocarditis during the vaccination campaign period is increased, a more comprehensive data collection on a wider scale should be done,” the researchers said. “We hope this report will serve as a reminder to report events and allow for analysis of potential adverse reactions.”

This case series involved patients diagnosed with perimyocarditis following vaccination. The researchers identified these patients from three paediatric medical centres in Israel through a network of paediatricians and data regarding the cases obtained. Additionally, they compared the incidence of perimyocarditis during the vaccination period with the previous years.

All patients (n=7) were males aged 16–18 years and of Jewish descent. They presented with chest pain that began 1–3 days after receiving the BNT162b2 vaccine (mean, 2.1 days). Symptoms began following the second dose in six patients and after the first dose in one. [Pediatr Infect Dis J 2021;40:e360-e363]

Of note, all cases of perimyocarditis were mild, and none of the patients required cardiovascular or respiratory support. Moreover, the incidence of perimyocarditis during the vaccination period was higher (1 January to 28 February 2021: n=10 cases) than in previous years (same period in 2018: n=2; 2019: n=4; 2020: n=2).

“Although these patients underwent thorough clinical and laboratory investigation, a specific aetiology to the development of perimyocarditis was not identified,” the researchers said.

“Considering the differential diagnosis and possible pathogenesis of the above cases, COVID-19 itself may still be suspected,” they added.

In adults, COVID-19–related myocardial involvement has been observed in both acute disease and in a cardiac magnetic resonance imaging performed in convalescing patients (ie, after an isolation period and at least 72 symptoms-free hours). [J Card Surg 2020;35:1988-2008; JAMA Cardiol 2020;5:1265-1273; JAMA Cardiol 2021;6:945-950]

In children and adolescents, COVID-19–related perimyocarditis has been described as part of multisystem inflammatory syndrome, which occurs in 0.2 percent to 0.6 percent of cases. However, myocarditis may also occur as the initial presentation of an infection in rare cases. [World J Clin Cases 2020;8:5250-5283]

“Even so, in most of our cases, no fitting exposure to an infected individual took place, and none of our patients tested positive for COVID-19 in polymerase chain reaction investigation,” the researchers said.

This is the first description of transient cardiac injury in children following the BNT162b2 vaccine; no such cases were reported in studies conducted throughout its developmental process, according to the researchers.

“Although adolescents were in fact included in the phase III testing performed by Pfizer, the trial included only 138 [participants] 16–18 years of age, and this small cohort is likely not to portray the full spectrum of potential adverse reactions following the vaccine,” they noted.

Israel was the first country to vaccinate all pretested age groups, which allows them to report a temporal association between the vaccine and potential complications.