ATLANTA—Concerns have been raised about a possible link between receipt of anthrax vaccine adsorbed and atrial fibrillation in military personnel without identifiable underlying risk factors or structural heart disease.

A study in Human Vaccines & Immunotherapies sought to determine if lone atrial fibrillation) was associated with the vaccine.1

To do that, researchers from the national Centers for Disease Control and Prevention in Atlanta conducted a retrospective population-based cohort study among U.S. military personnel who were on active duty during the period from Jan. 1, 1998, through Dec. 31, 2006.

Researchers used International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes to identify patients diagnosed with atrial fibrillation in the Defense Medical Surveillance System, and electronic records were screened to include only individuals without evidence of predisposing medical conditions.

In addition to using multivariable Poisson regression to estimate the risk of lone atrial fibrillation after exposure to AVA, the study team also evaluated possible associations with influenza and smallpox vaccines.

The study population included nearly three million military personnel followed for 11,329,746 person-years of service. Of those, 2,435 met the case definition for lone atrial fibrillation, contributing approximately 8,383 person-years of service.

Of that group, 36% of individuals received at least one dose of AVA, with a median person time observed post-exposure of 3.6 years.

Researchers said they found no elevated risk of diagnosed lone atrial fibrillation associated with AVA (adjusted risk ratio = 0.99; 95% confidence interval = 0.90, 1.09; p = 0.84). In addition, no elevated risk was observed for lone atrial fibrillation associated with influenza or smallpox vaccines given during military service.

“We did not find an increased risk of lone atrial fibrillation after AVA, influenza or smallpox vaccine. These findings may be helpful in planning future vaccine safety research,” study authors concluded.

McNeil MM, Duderstadt SK, Sabatier JF, Ma GG, Duffy J. Vaccination and risk of lone atrial fibrillation in the active component United States military. Hum Vaccin Immunother. 2018 Nov 16. doi: 0.1080/21645515.2018.1549453. [Epub ahead of print] PubMed PMID: 30444675.