What has been described about visual symptoms after TBE vaccination?

Fråga: What has been described about visual symptoms after TBE vaccination?

Sammanfattning: Visual disturbances after vaccination against TBE were described but the occurrence is rare. It is presumably immune-mediated and usually has a good prognosis for visual recovery.

Svar: Visual disturbances such as blurred vision, photophobia, eye pain as well as optic neuritis are listed as rare side effects to tick-borne encephalitis (TBE) vaccine (1).

The WHO adverse drug reactions register has in total 164 reports of visual disorders to TBE vaccine. These reports contains 92 ADR´s with visual impairment, 51 diplopia, 36 photophobia and 23 blurred vision (2).

In the Swedish adverse drug reactions registry BiSi, there are eleven reports on visual disorders (blurred vision, diplopia photophobia and transient loss of vision) in association to TBE vaccines(3). The symptoms were in most of cases accompanied with other non specific symptom such as fever, headache, dizziness, and myalgia. Onset occurred hours up to 3 weeks after inoculation. Early rapid onset occurred in one patient who suffered from loss of vision in one eye one hour after the second dose of FSME-Immun. The symptom had completely disappeared after 4 hours. Recurrent bout of complications were reported in one case. It was concerning 17-year-old girl who developed a short-term diplopia after the second dose of TBE-vaccine. One year later she received the third injection whereupon she developed a general convulsion two days after the injection was given. There were no abnormal findings in CSF analysis, CT scan and MRI in those cases where the investigations have been mentioned except in one where white matter changes were found in MRI. In this case a 54-year-old healthy woman developed an unilateral abducens nerve palsy in association with the third dose of TBE vaccines. A 3 months follow-up visit was completely unremarkable. Total resolution of symptoms spontaneously or after treatment with corticosteroid and acyclovir was described. Two patients had not recovered at the time of the report.

However, a thorough literature searches revealed no published case reports concerning visual disorders of TBE vaccines.

On the other hand neurological adverse effects of TBE vaccination were reported in several studies. Neuritis and neuropathies of peripheral nerves and cases with other sensory neuronal impairment such as smell impairment has been reported (4-5).

Furthermore there are several case reports on vision impairment and optic neuritis to other viral vaccines including measles, rubella, hepatitis A and B and influenza. Clinical features include periocular pain, abnormal visual acuity and visual field defects which peak over 1 to 2 weeks. The fundus appears normal but occasionally edema of the optic nerve head is observed. MRI white matter abnormalities can be found. A vast majority of patients were treated with corticosteroids and usually substantially improve over the following month. However, many patients continue to have residual visual dysfunction even when visual acuity improves (6,7).

There are two vaccines options for prophylaxis against TBE in Sweden, Encepur and FSME-Immun. Both are based on killed whole TBE virus adjuvanted to aluminium hydroxide. In contrast to live-attenuated viruses vaccines (e.g., measles, mumps, rubella, and poliovirus) in which they can cause symptomatic viral infections of the nervous system, vaccines produced from killed organisms may cause neurological reactions through an immune-mediated reaction. Immunological attack on nerve-antigens in the central and peripheral nervous system could be explained by the molecular similarity between the proteins of the viruses used for the vaccination and self antigens (6). Immune adjuvant aluminum hydroxide have been incriminated as well as one of the mechanisms responsible for these immune-mediated reactions (7).

We recommend that the case is reported as an adverse event to the Swedish medical products agency.