Experts have called for close monitoring of infants treated with an antiviral Covid drug after the corneas of a six-month-old baby in Thailand – who was given the medication – changed colour, taking on a “bluish hue”.
The child had developed a cough and fever and tested positive for the virus before being given a treatment that not been authorised or approved in the US.
A report on the case, published in Frontiers in Paediatrics, states that the baby was the youngest known patient to receive favipiravir, which has been studied in China, Japan, Italy, Canada, Egypt, Thailand, Iran, the UK and the US.
The Independent reports that the drug was originally designed to treat influenza, but doctors began using it to treat Covid in Wuhan, China, in 2020. It has also been used to treat Ebola.
Research has shown that, in some instances, it can help treat Covid-19. A systematic review and meta-analysis published in the journal Scientific Reports in 2021 looked at the available research on the drug and found Covid patients who took it were more likely to have shown signs of “significant clinical improvement” seven days after hospitalisation, compared with people who were not given the drug.
Those who took favipiravir were 7% less likely to require supplemental oxygen therapy than those who did not take the medication, and the mortality rate was also lower among people who took favipiravir.
However, the authors of the report said this finding wasn’t “statistically significant”.
“Overall, favipiravir possibly exerted no significant beneficial effect in the term of mortality in the general group of patients with mild to moderate Covid-19,” they wrote.
The report said the drug hasn’t been shown to benefit people with Covid who were not hospitalised.
Eye colour change
Within 18 hours of taking favipiravir, the child’s mother noted that his brown eyes had taken on a “bluish discoloration of the cornea”.
No other body parts, such as skin, nasal mucosa, or nails, appeared to have the same discoloration, the report’s authors wrote.
The infant’s Covid symptoms improved after three days of favipiravir; the doctor recommended he stop taking the medication, due to its effect on his eyes.
A few days later, his eyes had returned to their original colour, and he was examined by an ophthalmologist shortly thereafter.
This isn’t the first time favipiravir has changed a person’s eye colour. A separate case report published in the Indian Journal of Ophthalmology in 2021 presented the details of a 20-year-old man whose eyes changed from brown to blue after taking the medication for Covid-19.
He noticed the discolouration on day two of the treatment, and his eyes returned to their normal colour the day after he stopped taking the medication.
The authors of the Frontiers in Paediatrics report said it was “noteworthy” that it took longer for the baby’s eyes to return to normal. “The exact reason for this delay remains unclear; however, a decrease in urine excretion could be a plausible contributing factor,” they wrote.
Favipiravir has been known to cause other side effects aside from corneal discolouration, including temporary visual blurring, diarrhoea and mild hyperuricemia, which is characterised by elevated uric acid in the blood.
The authors who wrote about the six-month-old’s case emphasised the need to closely monitor children who are given favipiravir, given the side effects that have been linked to the medication.
“While favipiravir is currently the mainstay of oral antiviral treatment for children with Covid-19,” they wrote, “its safety profile in children who are still in the developmental stage is uncertain.”
Study details
Case report: Favipiravir-induced bluish corneal discoloration in infant with COVID-19
Paveewan Jiravisitkul, Saraiorn Thonginnetra, Rintra Wongvisavavit.
Published in Frontiers of Pediatrics on 19 April 2023
Abstract
This report describes a case of a male infant diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection who was prescribed favipiravir therapy. The mother noticed a discoloration of the child's eyes within 18 h of therapy, and the cornea returned to normal colour within 5 days of medication cessation. This case report highlights the need for monitoring of favipiravir therapy in children due to the potential side effect of corneal discolouration, which has not yet had its long-term effects identified.
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