and molecular mimicry may contribute to the symptoms of ADEM; however, the publications did not provide evidence linking these mechanisms to hepatitis A vaccine.

The committee assesses the mechanistic evidence regarding an association between hepatitis A vaccine and ADEM as weak based on knowledge about the natural infection.

Causality Conclusion

Conclusion 7.1: The evidence is inadequate to accept or reject a causal relationship between hepatitis A vaccine and ADEM.

TRANSVERSE MYELITIS

Epidemiologic Evidence

No studies were identified in the literature for the committee to evaluate the risk of transverse myelitis after the administration of hepatitis A vaccine.

Weight of Epidemiologic Evidence

The epidemiologic evidence is insufficient or absent to assess an association between hepatitis A vaccine and transverse myelitis.

Mechanistic Evidence

The committee did not identify literature reporting clinical, diagnostic, or experimental evidence of transverse myelitis after the administration of hepatitis A vaccine.

Weight of Mechanistic Evidence

While rare, hepatitis A infection has been associated with the development of transverse myelitis (Wasley et al., 2010). The committee considers the effects of natural infection one type of mechanistic evidence.

Autoantibodies, T cells, and molecular mimicry may contribute to the symptoms of transverse myelitis; however, the committee did not identify literature reporting evidence of these mechanisms after administration of hepatitis A vaccine.

The committee assesses the mechanistic evidence regarding an association between hepatitis A vaccine and transverse myelitis as weak based on knowledge about the natural infection.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement