On behalf of the TeamHealth Emerging Infectious Disease Taskforce
Introduction
Questions have arisen regarding a possible association between cases of Pericarditis/Myocarditis and COVID-19 vaccines. This mainly stems from an in-depth analysis of reports in the Vaccine Adverse Events Reporting System or (VAERS) presented by Tom Shimabukuro, MD on June 10, 2021.
Dr. Shimabukuro is a member of the CDC’s Vaccine Safety Team’s COVID-19 Vaccine Task Force. His presentation focused on the adverse and serious adverse events as reported to VAERS in the age range of 12 to 15 years. But it also included information on ages 16 to 25. Let’s examine the meaning of the VAERS report in a broad context.
What is The Vaccine Adverse Event Reporting System (VAERS)?
The Vaccine Adverse Event Reporting System (VAERS) was designed by the CDC and its partners to monitor vaccine safety in the United States. It has strengths and weaknesses.
First, the VAERS casts a wide net. The VAERS accepts all reports from everyone including non-clinicians (such as patients, parents, etc.) regardless of the plausibility that a vaccine may have caused the issue or the clinical seriousness of the issue. This is good in that a very wide spectrum of possible reactions can be reported easily and quickly by everyone. This can allow the VAERS to detect potential safety problems very quickly. In addition, this wide acceptance of information might detect the more rare adverse events that could be missed by more regimented information entry.
On the other hand, the data collected are of inconsistent quality and frequently incomplete making analysis problematic. There is also a huge level of reporting bias in the data because of the lack of standardization and the fact that the general public can enter reports without any medical training.
We point out some of these issues with the VAERS not to denigrate it, but rather to demonstrate the type and quality of the data. The conclusions that can be drawn from a data source are entirely dependent on the various factors present in the data itself.
Because of these factors, and the non-scientific structure (in the statistical sense) of the data collection, the VAERS cannot tell researchers if a vaccine is causing a problem. It can at best suggest an association that needs to be investigated. Sometimes the possible association is strong, but often it is weak requiring several layers of statistical analysis to find it. And this is where we are with the mRNA data and possible pericarditis/myocarditis.
What Do We Know Globally?
Globally, reports exist of inflammatory conditions such as pericarditis in individuals of all age ranges and risk factors after receiving any variety of COVID-19 vaccine. In fact, almost any vaccine for any disease of any type will have similar reports in the literature. The question is – “is the rate of adverse conditions potentially associated with a vaccine, greater than the risk of adverse conditions from contracting the disease?” So far, both globally and in the United States specifically, the rates of inflammatory problems found post-COVID-19 vaccination, are a magnitude of order lower than the risk of similar conditions from suffering a COVID-19 infection. This makes the COVID-19 vaccine the better option by far.
The Data so far in the United States
Using the VAERS data base, 57,126 reports with at least one health check during days 0–7 after the first vaccine dose, and 15,988 with at least one health check during days 0–7 after their second dose, the following was noted.
- When the VAERS data are dissected and subjected to several simple statistical processes a fairly weak “signal” arose that might indicate an association between any of the mRNA vaccines and cases of pericarditis/myocarditis mostly in male adolescents and young adults age 16 years or older.
- Pericarditis/myocarditis was noted more often after getting the second vaccine dose than after the first dose.
- The diagnosis was noted most commonly within 16 to 18 days after either the first or second COVID-19 vaccination.
- Although almost all the younger patients in the VAERS were admitted, all but a few were discharged within two days after consultations on standard therapy with no complications. This is consistent with other reports globally in individuals with pericarditis/myocarditis suspected to be COVID-19 vaccine related (Wise). All but a few are either treated as outpatients, or discharged stable after short periods of observation.
Current Recommendations
Due to the fact that any possible risk for pericarditis/myocarditis detected thus far is much lower than the risk of all serious inflammatory diseases from catching COVID-19, the CDC continues to recommend vaccination for COVID-19 down to age 12 as appropriate (CDC). This recommendation is the same as the World Health Organization and the European Health Organization.
Conclusions
As with any vaccine that stimulates the immune system, inflammatory problems such as pericarditis/myocarditis are possible complications. The level of possible association with mRNA vaccines in the United States is quite low and consistent with findings globally.
The vaccines provide significant protection against COVID-19. The risk of serious inflammatory problems and other serious conditions from COVID-19 infections themselves is much higher than the possible risk noted so far from any vaccine.
The recommendations from the CDC continue to be vaccination in everyone able to take a vaccine down to age 12. Studies are continuing to determine the safety and efficacy of the vaccines for even younger children.
As with any vaccine, this issue will continue to be monitored through the VAERS as well as individual organizations, institutions and researchers.
References
Ramírez-García A, Jiménez SL, Ximénez ID, et al. Pericarditis tras la administración de la vacuna de ARNm BNT162b2 contra la COVID-19 [Pericarditis after administration of the BNT162b2 mRNA COVID-19 vaccine]. Rev Esp Cardiol. 2021 Jun 12. Spanish. doi: 10.1016/j.recesp.2021.06.006. Epub ahead of print. PMID: 34149145; PMCID: PMC8196309. (HERE).
Wise J. Covid-19: Should we be worried about reports of myocarditis and pericarditis after mRNA vaccines? BMJ. 2021 Jun 24;373:n1635. doi: 10.1136/bmj.n1635. PMID: 34167952. (HERE).
Baradaran A, Malek A, Moazzen N, Abbasi Shaye Z. COVID-19 Associated Multisystem Inflammatory Syndrome: A Systematic Review and Meta-analysis. Iran J Allergy Asthma Immunol. 2020 Dec 19;19(6):570-588. doi: 10.18502/ijaai.v19i6.4927. PMID: 33463127. (HERE).
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Raymond TT, Das A, Manzuri S, Ehrett S, Guleserian K, Brenes J. Pediatric COVID-19 and Pericarditis Presenting With Acute Pericardial Tamponade. World J Pediatr Congenit Heart Surg. 2020 Nov;11(6):802-804. doi: 10.1177/2150135120949455. Epub 2020 Sep 10. PMID: 32909890; PMCID: PMC7484599. (HERE).
CDC: Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination. Accessed 7/7/2021 (HERE).
Imazio, M. COVID-19 as a Possible Cause of Myocarditis and Pericarditis: Expert Analysis, American College of Cardiology, Feb 05, 2021 (HERE).
WHO. COVID-19 subcommittee of the WHO Global Advisory Committee on Vaccine Safety (GACVS) reviews cases of mild myocarditis reported with COVID-19 mRNA vaccines. World Health Organization 26 May 2021. (HERE).