Natural viral infections with influenza, hepatitis A, measles, mumps and rubella and varicella have all been associated with myelitis, albeit rarely. Thus, these viral vaccines may prevent transverse myelitis by protecting against natural infection. Vaccines currently routinely recommended to the general population in the U.S. have not been shown to cause transverse myelitis.
The 2012 report by the Institute of Medicine (IOM), now called the National Academy of Medicine (NAM), found no relevant studies of quality in the literature assessing an association between transverse myelitis and MMR, varicella, influenza, hepatitis A, hepatitis B, HPV, meningococcal conjugate, diphtheria, tetanus or pertussis vaccines, since the only applicable studies available either had serious methodological limitations or used passive surveillance systems and therefore lacked an unvaccinated comparison group .
Two Vaccine Safety Datalink studies published since the 2012 IOM report found no cases of transverse myelitis in over 200,000 pregnant women within 42 days after receiving trivalent inactivated influenza vaccine  and in over 9,000 pregnant women within 42 days after receiving 2009 H1N1 pandemic influenza vaccine .
Natural infection with wild-type influenza, hepatitis A, measles, mumps and rubella viruses, as well as herpes zoster and reactivation of latent wild-type varicella virus, have all been associated with myelitis, albeit rarely. Mechanisms that could contribute to transverse myelitis include viral reactivation , as well as molecular mimicry, which refers to the possibility that similar epitopes shared between self-peptides and foreign peptides (introduced via infection or immunization) inadvertently cause the activation of autoreactive T or B cells, leading to autoimmunity.
The 2012 IOM report described a few cases of transverse myelitis after MMR [4-6], varicella , and hepatitis B vaccines , but even when also considering knowledge about the aforementioned natural infections the IOM concluded this mechanistic evidence was weak. The IOM also concluded that there was no mechanistic evidence for an association between transverse myelitis and HPV, meningococcal conjugate, diphtheria, tetanus and pertussis vaccines .
1. Institute of Medicine. In: Stratton K, Ford A, Rusch E, Clayton EW, eds. Adverse Effects of Vaccines: Evidence and Causality. Washington (DC): National Academies Press (US); 2012.
2. Nordin JD, Kharbanda EO, Benitez GV, et al. Maternal safety of trivalent inactivated influenza vaccine in pregnant women. Obstet Gynecol 2013;121:519-25.
3. Nordin JD, Kharbanda EO, Vazquez-Benitez G, Lipkind H, Lee GM, Naleway AL. Monovalent H1N1 influenza vaccine safety in pregnant women, risks for acute adverse events. Vaccine 2014;32:4985-92.
4. Holt S, Hudgins D, Krishnan KR, Critchley EM. Diffuse myelitis associated with rubella vaccination. Br Med J 1976;2:1037-8.
5. Joyce KA, Rees JE. Transverse myelitis after measles, mumps, and rubella vaccine. BMJ 1995;311:422.
6. Lim S, Park SM, Choi HS, et al. Transverse myelitis after measles and rubella vaccination. J Paediatr Child Health 2004;40:583-4.
7. LaRovere KL, Raju GP, Gorman MP. Postvaricella acute transverse myelitis in a previously vaccinated child. Pediatr Neurol 2008;38:370-2.
8. Tartaglino LM, Heiman-Patterson T, Friedman DP, Flanders AE. MR imaging in a case of postvaccination myelitis. AJNR Am J Neuroradiol 1995;16:581-2.