A rare case of bilateral optic neuritis post-Covishield (ChAdOx1-S [recombinant]) vaccination

Abstract

Multiple adverse effects have been reported in people receiving the COVID-19 vaccinations including few reports of optic neuritis. However, there is no report till date, of bilateral optic neuritis post-ChAdOx1-S (recombinant) vaccination. We report here, for the first time, such a case in a previously healthy woman. Although a direct causal relationship cannot be proven, there was a temporal association between the vaccination and the onset of optic neuritis. Some vaccine adjuvants inciting disproportionate systemic inflammation, molecular mimicry, and the hypercoagulable state seen after COVID-19 vaccination could be the possible causes for the development of optic neuritis. Clinicians should be aware of this adverse effect apart from various other adverse effects of COVID-19 vaccination.

Introduction

Coronavirus disease 2019 (COVID-19) is an ongoing global pandemic which is caused by the novel enveloped, plus-stranded, RNA coronavirus, namely severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

In India, three vaccines against COVID-19 have been granted emergency use authorization by the Central Drugs Standard Control Organization, namely, Covishield (ChAdOx1-S [recombinant]) (Oxford- AstraZeneca's vaccine manufactured by Serum Institute of India), Covaxin (manufactured by Bharat Biotech Limited), and Sputnik-V.

SARS-CoV-2 can cause variety of ocular manifestations including conjunctivitis, epiphora, episcleritis, central retinal vein occlusion, papillophlebitis, acute optic neuritis etc.[1] Similarly, COVID-19 vaccines cause variety of adverse effects such as injection site pain, headache, myalgia, fever, deep vein thrombosis, disseminated intravascular coagulation (DIC) etc.[2,3]

There are reports that COVID-19 vaccines can induce SARS-CoV-2 like inflammatory and demyelinating diseases.[4] There are few reports of optic neuritis following COVID-19 vaccinations in general, including post Pfizer and Moderna COVID-19 mRNA vaccines. However, there are no reports following ChAdOx1-S (recombinant) vaccination.[3,4,5,6,7]

Here, we report a rare case of bilateral optic neuritis post-ChAdOx1-S (recombinant) vaccination. To the best of our knowledge, this is the first report of such a case.

Case Report

A 44-year-old female presented with blurring of vision in her left eye, 4 days after receiving the second dose of Covishield (ChAdOx1-S [recombinant]) vaccine (Batch No. 4120Z011). She had developed cough and cold 2 days after the second dose, for which she took antiallergic medicines. She complained of sudden onset of severe blurring of vision in the left eye on the morning of 4^th day, which lasted for about half an hour. Her vision impairment improved over time following the episode, but blurred vision still persisted. There was no history of fever, injection site pain, or eye pain. She denied a history of any systemic illness. On examination on the same day, her best-corrected visual acuity (BCVA) was 6/6p in both the eyes, with −7 diopter (D) in the right eye and −6.25 D in the left eye. Pupillary reactions were within normal limit (WNL). The right eye optic disc was hyperemic with obscuration of the cup, but margins were sharp and vessels were normal, suggestive of mild disc edema [Figure 1a]. The left eye optic disc was also hyperemic with obscuration of cup and margins were blurred, indicating optic disc edema. Vessels were tortuous and dilated [Figure 1b]. There were three superficial hemorrhages in the mid-periphery of inferonasal area of the left eye. Intraocular pressures, color vision, and contrast sensitivity were WNL in both the eyes.

Figure 1:

(a) Fundus picture of the right eye showing the optic disc which is reddish in color, cup-disc ratio is obliterated but margins are sharp and vessels are normal, suggestive of mild disc edema. (b) Fundus picture of left eye showing the optic disc which is elevated and reddish in color, cup-disc ratio is obliterated and margins are blurred, indicating optic disc edema. Vessels are tortuous and dilated

Next day, she had a similar episode. The mild blurring persisted after this episode also.

Blood investigations showed platelet count of 1, 05,000/mcL and ESR 68 mm/h. The rest were WNL. Visual evoked potential (VEP) showed prolonged P-100 latencies from both the sides: 181.8 ms in the right eye and 178.5 ms in the left eye [Figure 2a]. Humphrey visual field analysis (HFA 30-2) revealed enlarged blind spot in the left eye and depressed peripheral fields in both the eyes [Figure 3a]. Retinal nerve fiber layer (RNFL) thickness was decreased in both the eyes in OCT. In fundus fluorescein angiography, the right eye was WNL, whereas the left eye showed leakage of dye from the optic disc in the late phase [Figure 2c]. Contrast-enhanced magnetic resonance imaging brain and spine were WNL, but orbits showed optic disc swelling in the left eye [Figure 2b]. A diagnosis of bilateral optic neuritis (atypical) post-COVID-19 vaccination, left more than right, was made. Serum antimyelin oligodendrocyte glycoprotein could not be carried out since it was not available commercially. She refused for cerebrospinal fluid analysis.

Figure 2:

(a) VEP at presentation showing prolonged P-100 latencies in both the eyes. (b) Contrast enhanced MRI of brain WNL and orbits showing optic disc swelling in left eye. (c) Fundus fluorescein angiography of left eye showing leakage of dye from the optic disc in the late phase. (d) VEP at 1-month follow-up showing improvement in the P-100 latencies in both the eyes. VEP: Visual evoked potential, MRI: Magnetic resonance imaging, WNL: Within normal limit

Figure 3:

(a) HFA 30-2 of both the eyes at presentation, showing enlarged blind spot in the left eye and depressed peripheral fields in both the eyes. (b) HFA 30-2 at 1-month follow-up showing improvement of visual field defects in both the eyes, left improving more than the right. HFA: Humphrey visual field analysis

She was advised to consider taking intravenous methyl prednisolone pulse therapy, but she declined.

At 1-month follow-up, her BCVA was 6/6p in both the eyes. Color vision, contrast sensitivity, and blood parameters were WNL. Surprisingly, the right eye was worse in other parameters. Grade 1 (one) RAPD was noted in the right eye but normal pupillary reaction in the left. There was slight improvement in the fundus picture in both the eyes. VEP latency improved in both the eyes to 105.0 ms in the right eye and 106.2 ms in the left eye [Figure 2d]. The visual field defects in HFA 30-2 improved in both the eyes, left improving more than the right [Figure 3b].

Discussion

Covishield is a Chimpanzee adenovirus encoding the SARS-CoV-2 spike glycoprotein ChAdOx1-S (recombinant). It is a viral vector type of vaccine. There are reports of multiple adverse effects including thromboembolism, DIC, and optic neuritis in people who received the COVID-19 vaccines.[2,3,4,5,6,7]

Optic neuritis is inflammation of the optic nerves, involving one or both eyes. It occurs due to many causes such as demyelination, infections, and inflammations, including postvaccination.[8] Atypical optic neuritis is bilateral, painless, and has pronounced disc edema.

Our patient developed symptoms and signs just 4 days after receiving the second dose of Covishield vaccination. Hence, there is a temporal association between the vaccination and the development of the bilateral optic neuritis. She had mild thrombocytopenia too.

The mechanism for optic neuritis following vaccination is not clearly understood till now. However, there are some hypotheses for it. First, some vaccine adjuvants are believed to induce activation of NLRP3 inflammation, which incites disproportionate systemic inflammation in human body tissues.[9] Second, molecular mimicry is also thought to be one of the causes where viral proteins cause immune cross-reactivity with human tissues.[10] Third, COVID-19 vaccines can cause thromboemboli[2] which can possibly lodge at the lamina cribrosa region of the optic nerve head and possibly cause the optic disc edema.

Conclusion

COVID-19 vaccinations can cause variety of adverse effects. However, development of bilateral optic neuritis following ChAdOx1-S (recombinant) vaccine has not been reported so far. Although it is not possible to prove a direct causal relationship, there was a temporal association between the vaccination and the onset of optic neuritis in our case of a previously healthy woman. Some vaccine adjuvants inciting disproportionate systemic inflammation, molecular mimicry, and the hypercoagulable state seen after COVID-19 vaccination could be the possible causes for the development of optic neuritis.

Clinicians should be aware of this particular adverse effect among the myriad of adverse effects of COVID-19 vaccinations.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.