Dr Musa Mohd Nordin, Paediatrician
Dr Zulkifli Ismail, Paediatric Cardiologist
Asst Prof Mohammad Farhan Rusli, Public Health Physician
11 January 2022
The bulk and thrust of the concerns of the signatories (Concerned Malaysian Medical Practitioners) of the letter to the Prime Minister, Health Minister and Majlis Keselamatan Negara revolves around the association of the COVID-19 mRNA vaccines with the risk of acute myocarditis (point numbers 7 to 15).
This brief, really a summary of excellent review articles, will examine the evidence, notably the risk-benefit analysis, related to their concerns and allegations and demonstrate that their allegations are unfounded and their concerns totally misplaced.
Acute myocarditis is often associated with a viral infection and the SARS-CoV-2 is no exception. Prior to the advent of COVID-19, the estimated incidence of viral myocarditis was 10-22 cases per 100,000 persons. 
The largest population study to date of acute cardiac outcomes estimated an extra 40 myocarditis events per 1 mi l l ion due to SARS-CoV-2. 
Th is is at least 4-40 times higher than mRNA vaccine-associated myocarditis which is estimated at 1-10 per 1 million vaccinated persons in multiple studies. [2-6]
As in post-viral myocarditis, mRNA vaccine-associated myocarditis occurs mainly in young males, under 20 years, and usually after the second mRNA vaccine dose. The estimated reported rates was 67 per mi llion. The majority of the cases present within one week of the mRNA vaccination. 
In young males, myocarditis due to COVID-19 was estimated to occur at a rate as high as 450 per million. Therefore, young males infected with SARS-CoV-2 are at least 6 times more likely to develop myocarditis compared to those who have received the mRNA vaccine.With the upcoming immunization of children 5-11 years old, parents should be further reassured that the risk of post-mRNA vaccine myocarditis is remarkably low. Only 11 cases were reported from a total of 8.7 million doses and all have virtually recovered. 
Overall, the clinical course of post mRNA vaccine-associated myocarditis is mild and the outcome is very good with a survival rate in excess of 99%. More than 90% of the patients recover their cardiac function within a few weeks of the injury. (10)
In contrast, COVID-19 associated myocarditis runs a much higher risk of cardiac injury. 10% of COVID-19 outpatients and 40% of inpatients have significant cardiac complications in the absence of coronary artery disease. The low oxygen, shock syndrome, blood clots, bleeding and vessel injury seen in patients with COVID-19 further compound the myocardial damage. The survival rate following COVID-19 associated myocarditis is much lower, between 30-80%. (11).
And whilst we are still discussing about the acute conditions of the heart, we would like to draw attention to a whole series of chronic cardiac injuries and complications following Long COVID. (12)
Over the course of a one-year follow-up, survivors of COVID-19 showed a significantly increased risk and burden of cerebrovascular disorders, dysrhythmias, inflammatory heart disease, ischemic heart disease, heart failure, thromboembolic disease, and other cardiac disorders.
Apart from the acute myocarditis which we have earlier described, the COVID-19 pandemic has also caused a significant increase in the global burden of other chronic debilitating cardiovascular diseases. This will further burden the already overwhelmed health systems worldwide.
We have confined ourselves to the main allegation of the letter, namely the lack of safety of the mRNA vaccines and its causation of acute myocarditis. We are sure our other colleagues and medical professional organisations wil address the other preposterous allegations and anti-vaccine nuances of the aforementioned letter. The letter is very reminiscent of Wakefield’s withdrawn publication in the Lancet, regarding MMR and Autism. We must follow the science and not present data in snippets to further push an extremely dangerous and malicious agenda.
We have shared incontrovertible evidence which debunks their allegations and we would advocate the continued use of mRNA vaccines, to mitigate COVID-19 cases, hospitalisations, ICU admissions, deaths and to exit us from the pandemic.
From a public health perspective, vaccines serve as the best protection against new and emerging variants, especially now with the opening of schools, public spaces and the NRP 2.0 where border restrictions will be reduced. As the number of paediatric cases are rising in the US, the UK and Europe, we must take heed and encourage the vaccinations for these very vulnerable populations.
1. Myocarditis following the mRNA vaccines are rare.
2. Myocarditis due to COVID-19 is very much higher than following the mRNA vaccines.
3 The mRNA vaccine-associated myocarditis are mild and the outcome is good.
4. The myocarditis due to COVID-19 is associated with a much higher risk of myocardial injury, complications and death.
5. Evidence based risk benefit assessment shows that the mRNA vaccines are overwhelmingly favorable and safer compared to COVID- 19 acquired myocarditis and should continue to be recommended.
6. The cardiovascular diseases associated with Long COVID can be mitigated with the increased and better utilisation of the mRNA vaccines
3. Witberg, G. et al. Myocarditis after Covid-19 vaccination in a large health care organization. N. Engl. J. Med. https://doi.org/10.1056/NEJMoa2110737 (2021).
4. Mevorach, D. et al. Myocarditis after BNT162b2 mRNA vaccine against Covid-19 in Israel. N. Engl. J. Med. https://doi.org/10.1056/NEJMoa2109730 (2021).
5. Klein, N. P. et al. Surveillance for adverse events after COVID-19 mRNA vaccination. JAMA 326, 1390–1399 (2021).6. Montgomery, J. et al. Myocarditis following immunization with mRNA COVID-19 vaccines in members of the US Military. JAMA Cardiol. 6, 1202–1206 (2021).
10. Aikawa, T., Takagi, H., Ishikawa, K. & Kuno, T. Myocardial injury characterized by elevated cardiac troponin and in-hospital mortality of COVID-19: an insight from a meta-analysis. J. Med. Virol. 93, 51–55 (2021).