Incidence Rates and Clinical Characteristics of Patients With Confirmed Myocarditis or Pericarditis Following COVID-19 mRNA Vaccination: Experience of the Veterans Health Administration Through 9 October 2022

Background

Although the benefits outweigh the risks, COVID-19 vaccines have been associated with an increased risk of myocarditis and pericarditis. This report is based on a national US veteran population with confirmed myocarditis/pericarditis following mRNA COVID-19 vaccines according to the near real-time active surveillance program of Veterans Affairs.

Methods

This study is based on a cohort evaluation of all adults administered ≥1 mRNA COVID-19 vaccine, including boosters, in the Veterans Health Administration between 14 December 2020 and 9 October 2022. ICD-10-CM diagnosis codes were used to identify potential safety signals in near real time through a database analysis. All potential cases of myocarditis/pericarditis identified in the database analysis underwent in-depth chart review and case validation by a team of pharmacists and expert clinicians. Our main outcome was the incidence rate of confirmed myocarditis/pericarditis among vaccine recipients (overall and those aged 18-39 years) within 21 days of a first, second, or booster dose of a mRNA COVID-19 vaccine. We calculated the ratio of observed events among COVID-19 vaccine recipients over expected events from historical vaccine recipient controls (2015-2020) in the Veterans Health Administration. We used confirmed cases to calculate incidence rates and 95% CIs.

Results

Through 9 October 2022, 3 877 453 doses of BNT162b2 (Pfizer-BioNTech) and 4 221 397 doses of mRNA-1273 (Moderna) were administered as first or second dose across Veterans Affairs, and 1 012 561 BNT162b2 and 1 156 160 mRNA-1273 booster doses were administered. Among all doses, the rapid cycle analysis identified 178 potential cases of myocarditis/pericarditis among vaccinees of any age and 22 potential cases among those aged 18-39 years. Of these, 33 cases, including 6 among those 18-39 years old, were confirmed after in-depth chart review and validation, corresponding with an overall incidence rate per million ranging from 0.46 (95% CI, .01-2.55) for Moderna dose 1 to 6.91 (95% CI, 2.78-14.24) for Pfizer booster. Among those aged 18-39, incidence rates ranged from 7.1 (95% CI, .18-39.56) for Moderna dose 2 to 19.76 (95% CI, 5.38-50.58) for Pfizer dose 2. Patients with confirmed cases were hospitalized for a mean 4.1 days (range, 1-15). The final disposition for 32 (97%) of 33 cases was discharge to home.

Conclusions

This report is a real-world demonstration of the Veterans Affairs' active surveillance system for vaccines. Although the rapid cycle analysis initially identified 178 potential cases of myocarditis/pericarditis, only 1 of 5 cases was confirmed to be related to a COVID-19 vaccine after chart review. These findings highlight the paramount importance of active surveillance and chart validation for rare but serious adverse events related to COVID-19 vaccines.

Comparison of hospitalization costs for the same adverse reaction associated with different medications

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Costs of hospitalization due to severe adverse drug reactions (ADRs) were previously estimated within the Veterans Health Administration (VHA), but additional analyses are needed to infer potential interventions to mitigate these negative outcomes. The objective of the current study was to compare specific adverse reaction-related hospitalization costs between medications with similar indications.

METHODS

Mean hospitalization costs associated with the same ADR symptom were compared for different drugs with similar indications using adjusted generalized linear models with a Bonferroni correction for multiple comparisons as well as a gamma distribution.

RESULTS

Overall, hospitalization costs between medications with similar indications were not significantly different for specific adverse reactions. However, gastrointestinal hemorrhage-associated costs were higher for warfarin versus nonsteroidal anti-inflammatory drugs (model estimate of mean cost, $18,114 [range of lower and upper model estimates, $12,522-$26,202] vs $14,255 [estimate range, $9,710-$20,929]). Similarly, the estimated mean hospitalization cost associated with angioedema was higher for losartan versus lisinopril or lisinopril/hydrochlorothiazide: $14,591 (range, $9467-$22,488) versus $8,935 (range, $6,301-$12,669) and $8,022 (range, $5,424-$11,865), respectively.

CONCLUSION

Although we found few differences in the cost of hospitalization when comparing drugs with similar indications and the same adverse reaction, there were specific drug-ADR pairs that merit attention and consideration of interventions to improve safe and appropriate medication use. Evaluation of the effect of those interventions on the incidence of ADRs is an area for future study.