Watch for Keratitis When Administering Varicella Vaccine

Pharmacists should watch for signs of keratitis after administering the varicella vaccine for chickenpox and shingles.

Researchers from the University of Missouri School of Medicine recently discovered a link between the vaccine and corneal inflammation in rare cases. In light of this finding, patients with a history of eye inflammation should consult a health care provider before getting vaccinated against varicella zoster virus, they advised.

After studying more than 12 million case reports from national and international registries, the researchers uncovered at least 20 cases of keratitis in children and adults that occurred within a month of varicella vaccine administration. The symptoms of keratitis developed within 24 days of vaccination among the adults and within 14 days among the children.

“The vaccine is a live virus, and in rare, susceptible individuals, this can cause a reaction in the eye in the form of herpes-zoster keratitis,” Frederick W. Fraunfelder, MD, MBA, director of the National Registry of Drug-Induced Ocular Side Effects and chair of the Department of Ophthalmology at the MU School of Medicine, explained to Pharmacy Times.

According to Dr. Fraunfelder, pharmacists should keep the following things in mind when administering the varicella vaccine.

1. Ask questions about eye health history before administering the vaccine.

Dr. Fraunfelder said pharmacists should ask patients the following 2 questions:

· Do you have a history of zoster or shingles in or around the eye(s)?

· Do you have a past ocular history of herpes virus affecting your eyes?

2. Keep in mind that keratitis can occur in patients with no prior eye-related problems.

“Most of the keratitis cases reported [in the study] occurred without any prior eye-related events. This is especially true in the pediatric age group who get chickenpox vaccines,” Dr. Fraunfelder noted.

3. Counsel patients about the rare risk of varicella vaccine-related keratitis.

Pharmacists should inform patients about the rare risk of a zoster-keratitis reaction, especially those who have experienced it in the past.

“It is helpful to be informed, and if a reaction occurs, [the patient] probably shouldn't get the vaccine ever again,” Dr. Fraunfelder said.

4. Look for eye symptoms after vaccination.

“Blurred vision, red eye, cloudy cornea, and light sensitivity are some warning signs that can start appearing within days to weeks after administration,” Dr. Fraunfelder said.

5. If keratitis symptoms present, refer the patient to an ophthalmologist.

“Referral to an ophthalmologist is important, as the long-term sequelae of the condition can be minimized with treatment,” Dr. Fraunfelder explained. “After that, a subspecialist would administer steroids and/or antivirals.”