Reactivation of Herpes Simplex Keratitis on a Corneal Graft Following SARS-CoV-2 mRNA Vaccination

Herpes simplex keratitis: A brief clinical overview

The aim of our minireview is to provide a brief overview of the diagnosis, clinical aspects, treatment options, management, and current literature available regarding herpes simplex keratitis (HSK). This type of corneal viral infection is caused by the herpes simplex virus (HSV), which can affect several tissues, including the cornea. One significant aspect of HSK is its potential to cause recurrent episodes of inflammation and damage to the cornea. After the initial infection, the HSV can establish a latent infection in the trigeminal ganglion, a nerve cluster near the eye. The virus may remain dormant for extended periods. Periodic reactivation of the virus can occur, leading to recurrent episodes of HSK. Factors triggering reactivation include stress, illness, immunosuppression, or trauma. Recurrent episodes can manifest in different clinical patterns, ranging from mild epithelial involvement to more severe stromal or endothelial disease. The severity and frequency of recurrences vary among individuals. Severe cases of HSK, especially those involving the stroma and leading to scarring, can result in vision impairment or even blindness in extreme cases. The cornea's clarity is crucial for good vision, and scarring can compromise this, potentially leading to visual impairment. The management of HSK involves not only treating acute episodes but also implementing long-term strategies to prevent recurrences and attempt repairs of corneal nerve endings via neurotization. Antiviral medications, such as oral Acyclovir or topical Ganciclovir, may be prescribed for prophylaxis. The immune response to the virus can contribute to corneal damage. Inflammation, caused by the body's attempt to control the infection, may inadvertently harm the corneal tissues. Clinicians should be informed about triggers and advised on measures to minimize the risk of reactivation. In summary, the recurrent nature of HSK underscores the importance of both acute and long-term management strategies to preserve corneal health and maintain optimal visual function.

COVID-19 vaccination and corneal allograft rejection- a review

Aim

To provide a comprehensive literature review on the perceived correlation between COVID-19 vaccination and corneal allograft rejection, and to characterize risk factors, time course, graft outcomes and proposed immunological basis.

Methods

A literature review was conducted in August 2023 using 4 electronic databases: PubMed, EMBASE, MEDLINE and Scopus. Articles were sourced using key words associated with COVID-19 vaccination and corneal graft. All articles were screened for relevance by abstract review. Duplicates and articles related to COVID-19 infection were excluded. No time limits were set. Additional literature searches regarding cause of corneal graft rejection, rates of graft rejection associated with other vaccines and the cellular mechanism of rejection were also performed.

Results

262 articles were identified from the literature search. 37 papers were included in the analysis based on defined inclusion criteria. This consisted of systematic reviews (n=6), review articles (n=5), retrospective studies (n=3), case series (n=8), letter to the editor (n=1) and case reports (n= 14). The majority of reported allograft rejections were in penetrating keratoplasties. Risk factors for COVID-19 vaccination associated rejection were previous allograft rejection episodes, repeat grafts and penetrating keratoplasty. Most reported rejection episodes were mild and resolved with treatment. Notably, several studies reported nil increase in corneal allograft rejection episodes over the COVID-19 vaccination period. Rejection episodes are associated with a broad spectrum of other vaccines and the complete pathophysiology is undetermined.

Conclusion

Corneal allograft rejection appears to be a rare complication of COVID-19 vaccination most frequently observed in high-risk corneal transplants. The true extent of this correlation remains controversial; however, clinician awareness of this risk is essential to its mitigation. Patient counselling around symptom monitoring following vaccination and discussion around topical steroid prophylaxis may be prudent.

Herpesviruses reactivation following COVID-19 vaccination: a systematic review and meta-analysis

BACKGROUND

The reactivation of herpesviruses (HHV) in COVID-19 patients is evident in the literature. Several reports have been published regarding the reactivation of these viruses (HSV, VZV, EBV, and CMV) among those who got COVID-19 vaccines. In this study, we aimed to review the current evidence to assess whether HHVs reactivation has any association with the prior administration of COVID-19 vaccines.

METHODS

A systematic search was conducted on 25 September 2022 in PubMed/MEDLINE, Web of Science, and EMBASE. We included all observational studies, case reports, and case series which reported the reactivation of human herpesviruses following administration of COVID-19 vaccines.

RESULTS

Our systematic search showed 80 articles that meet the eligibility criteria. Among the evaluated COVID-19 vaccines, most of the vaccines were mRNA based. Evidence from observational studies showed the possible relation between COVID-19 vaccine administration and VZV and HSV reactivation. The results of our proportion meta-analysis showed that the rate of VZV reactivation among those who received the COVID-19 vaccine was 14 persons per 1000 vaccinations (95% CI 2.97-32.80). Moreover, our meta-analysis for HSV reactivation showed the rate of 16 persons per 1000 vaccinations (95% CI 1.06-46.4). Furthermore, the evidence from case reports/series showed 149 cases of HHV reactivation. There were several vaccines that caused reactivation including BNT162b2 mRNA or Pfizer-BioNTech (n = 76), Oxford-AstraZeneca (n = 22), mRNA-1273 or Moderna (n = 17), Sinovac (n = 4), BBIBP-CorV or Sinopharm (n = 3), Covaxin (n = 3), Covishield (n = 3), and Johnson and Johnson (n = 1). Reactivated HHVs included varicella-zoster virus (VZV) (n = 114), cytomegalovirus (CMV) (n = 15), herpes simplex virus (HSV) (n = 14), Epstein-Barr virus (EBV) (n = 6), and HHV-6 (n = 2). Most cases reported their disease after the first dose of the vaccine. Many patients reported having comorbidities, of which hypertension, diabetes mellitus, dyslipidemia, chicken pox, and atrial fibrillation were common.

CONCLUSION

In conclusion, our study showed the possible association between COVID-19 vaccination and herpesvirus reactivation. The evidence for VZV and HSV was supported by observational studies. However, regarding other herpesviruses (EBV and CMV), further research especially from observational studies and clinical trials is required to elucidate the interaction between COVID-19 vaccination and their reactivation.

Corneal Adverse Events Associated with SARS-CoV-2/COVID-19 Vaccination: A Systematic Review

Vaccines against coronavirus disease 2019 (COVID-19) have played an important global role in reducing morbidity and mortality from COVID-19 infection. While the benefits of vaccination greatly outweigh the risks, adverse events do occur. Non-ocular adverse effects of the vaccines have been well-documented, but descriptions of ophthalmic effects remain limited. This systematic review aims to provide an overview of reported cases of corneal adverse events after receiving vaccination against COVID-19 and to compile existing clinical data to bring attention to these phenomena. Our review discusses corneal graft rejection, including proposed mechanisms, herpetic keratitis, and other reported corneal complications. Ophthalmologists and primary care physicians should be aware of such possible associations.

COVID-19 Vaccine-Associated Ocular Adverse Effects: An Overview

BACKGROUND

To address the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), vaccination efforts were initiated across the globe in December 2020 and are continuing. We report the onset interval and clinical presentations of ocular adverse effects following SARS-CoV-2 vaccination.

METHODS

For this narrative review, articles in the English language, published between 1 January 2020 to 1 September 2022, were included to formulate a list of the reported ocular adverse effects of different COVID-19 vaccines.

RESULTS

During this period, ocular adverse effects have been reported with BNT162b2 (Pfizer), mRNA-1273 (Moderna), AZD-1222 (AstraZeneca), and Ad26.COV2.S (Johnson & Johnson) vaccines. Endothelial graft rejection, herpes simplex virus keratitis, herpes zoster ophthalmicus, anterior uveitis, eyelid edema, purpuric rashes, ischemic optic neuropathy, and cranial nerve palsies were the most reported with BNT163b2. Retinal hemorrhages, vascular occlusions, and angle closure glaucoma were the most reported with AZD-1222. Most of the ocular adverse effects reported in the literature had a good to fair prognosis with appropriate management.

CONCLUSIONS

Evidence regarding the ocular adverse effects does not outweigh the benefits of SARS-CoV-2 vaccination in patients with pre-existing systemic or ophthalmic diseases. This review provides insights into the possible temporal association between reported ocular adverse events and SARS-CoV-2 vaccines; however, further investigations are required to identify the link between potential causality and pathological mechanisms.

Inhibitory activity of aqueous extracts of tea compositions, individual ingredients for their preparation and some plants against replication of Herpes simplex virus type 2 <i>in vitro</i>

Aim. In vitro analysis of the inhibitory activity of aqueous extracts of tea compositions, plant raw materials and as well as plants from different families against replication of Herpes simplex virus type 2.

Material and Methods. The viral strain MS of HSV‐2 was passivated on Vero cell culture. Antiviral (inhibitory) activity of aqueous extracts was studied in vitro according to the classical scheme of neutralization (inactivation) of the virus.

Results. For comparison we used control samples of aqueous extracts of Chaga mushroom (Inonotus obliquus) and grass of Alchemilla vulgaris L. with EC50 equal to 21.36±3.92 and 39.67±8.75 µg/ml (for dry raw materials) versus 103  PFU/ml HSV‐2. As a result the prevailing activity (from 15.25±3.92 to 1.71±0.54 µg/ml) was identified for extracts of tea compositions based on black and green tea, as well as individual ingredients for their composition – black tea, leaves of Mentha piperita L.,  flowers  of  Lavandula  angustifolia  Mill. and  clove  spices  (Syzygium aromaticum L.). Extracts obtained from plants that are not part of tea compositions of interest are fermented leaves of Epilobium angustifolium L. (Onagraceae) and grass of two species Euphorbia (E. pilosa L. and E. esula  L.,  Euphorbiaceae)  with  inhibitory  activity  at  concentrations  of 10.675±1.96; 2.29±0.57 and 1.71±0.54 µg/ml, respectively.

Conclusion. The results presented can become the basis for the search for individual biologically active substances of plant origin that inhibit HSV‐2 replication as well as for the development of effective medicines in the form of tea beverages and/or formulations for topical use to reduce relapses of chronic herpes.