Chickenpox vaccine may cause eye inflammation: study

A vaccine for chickenpox and shingles, which has been in use for more than 20 years and is considered an essential medicine by the WHO, may cause eye inflammation in some rare instances, a new study has claimed.
"Keratitis, or inflammation of the clear layer on the front of the eye, is a vision issue that can cause serious complications or even permanent damage to your vision if left untreated," said Frederick W Fraunfelder, from the University of Missouri School of Medicine in US.
"By studying case reports from national and international registries, we found at least 20 cases of keratitis occurred in children and adults within a month of administration of the chickenpox and shingles vaccine," said Fraunfelder.

"While this is a rare occurrence, it's important for physicians to know when giving the vaccine to individuals who have a history of the condition because it could be reactivated by the vaccine," he said.
A review of the database and previously published reports found 20 cases of keratitis with a close relationship to administration of the varicella zoster virus vaccine, the researchers said.
For adults, symptoms of keratitis developed within 24 days of vaccination. For paediatric patients, symptoms of inflammation developed within 14 days.

Using the World Health Organisation (WHO) classification system for adverse drug reactions, the researchers found a probable relationship between the vaccine and keratitis.

However, the researchers recommend the majority of patients still be regularly vaccinated against chickenpox and shingles.
"It's important to note that keratitis associated with these vaccines is very rare, and by itself is not a reason to forego vaccination," Fraunfelder said.
"But for patients who have a history of keratitis, we recommend they talk to their primary care physician before getting vaccinated," he said.
"If these individuals are vaccinated, they should be closely monitored to ensure they don't experience corneal inflammation or additional scarring," he said.