Could COVID be behind the pink-eye epidemic?

As Pakistan battles with a conjunctivitis, which has seen nearly 400,000 people since the start of the year infected, speculation has arisen as to what might be driving the virus’s spread.

The outbreak of pink eye saw over 50,000 schools shuttered at the start of October in an attempt to stem the spread of the viral infection.

Conjunctivitis is an inflammation of the mucous membrane covering the front of the eye and eyelids, usually caused by a bacterial or viral infection. The Pakistan outbreak is known to be due to a virus.

As conjunctivitis is a symptom of some COVID variants, is it possible that COVID may be the virus causing the outbreak?

“Pink eye was reported as a symptom of the original variants causing COVID-19, but became less common with later subvariants,” Catherine Bennett, an Alfred Deakin Professor of epidemiology and health at Deakin University, Australia, told Newsweek.

“Children were relatively spared from infection in those early waves, but with later subvariants better able to establish an infection in kids we heard of more cases of pink eye. This year in April-May, reports of conjunctivitis were on the rise as XBB 1.18 and other related subvariants of Omicron swept through countries like the U.S.”

“As new highly infectious Omicron variants become established in a country we see the overall number of infections rise as immunity created in the previous wave starts to wane, and these new variants have an edge because they are not as recognizable to our immune system,” she said.

Conjunctivitis can be caused by COVID-19 viruses due to the virus binding to structures in the eye and conjunctiva, causing inflammation.

“The SARS-CoV-2 virus spike protein binds to the ACE2 receptors on our cells to infect our bodies,” Neil A. Mabbott, the personal chair in immunopathology and head of the immunology division at the University of Edinburgh, Scotland, told Newsweek. “These ACE2 receptors are present on the membrane (the conjunctiva) that protects the eye. Further research is needed to determine whether the mutations in the spike protein of the XBB.1.16 COVID-19 variant enable it to bind more easily to the ACE2 receptors in the conjunctiva and infect the eye.”

However, conjunctivitis is a relatively uncommon symptom of COVID, making it unlikely to be seen in so many people across Pakistan if COVID were the cause.

“Conjunctivitis is a known symptom of COVID and has been known from the very early months of the pandemic, though back then it was not very common, about 1 to 2 percent of infections being slightly more common in people with severe disease,” Paul R. Hunter, a professor in medicine at the University of East Anglia, England, told Newsweek. “It is not clear to me how much if at all that early estimate has changed over the past three years. “

There is therefore no real evidence supporting COVID causing the outbreak in Pakistan. Adenoviruses are a much more common cause of conjunctivitis, making it more likely that the outbreak is caused by one of these.

“Daily reported cases of COVID-19 have been relatively low in Pakistan over the last few weeks,” Sarah Pitt, a lecturer in microbiology and biomedical science at the University of Brighton, England, told Newsweek. “Like many countries they are not doing extensive testing, but if cases were dramatically on the rise, there would be a rise in daily cases through hospitalization (as we are currently seeing in U.K. and U.S.)”

“I found a peer-reviewed paper from India which looked at conjunctivitis during the Delta variant COVID outbreak. The researchers did detailed analysis of the viruses from patient samples and found that most cases were caused by adenovirus. The second most common virus was COVID and it accounted for 11 percent of cases,” she said.

“So while the outbreak in Pakistan could be associated with COVID-19, more detailed viral investigations will be needed to ascertain this either way. Reports of a recent outbreak of conjunctivitis in Northern India suggest it was caused by either adenovirus or enteroviruses which are the most common causes of viral conjunctivitis, particularly in children.”

Others have suggested that an alternative driver of the outbreak could be the recent monsoon weather across the country.

“In terms of what is driving the Pakistan outbreak, the report I read suggested that this has followed the monsoon, and that a similar outbreak occurred in India when the monsoon arrived. Infections tend to increase at the onset of the monsoon,” Thea van de Mortel, a professor of nursing at Griffith University, Australia, told Newsweek.

Regardless of which virus is causing the outbreak, the experts advise standard hygiene practices to prevent the spread of the infection, as well as keeping up to date on CVOID vaccines in case COVID is the cause.

“Vaccination is by far the safest means to protect against the harmful effects of COVID-19 infection. Similarly, covering the mouth when coughing or sneezing, hand washing, not touching or rubbing the eyes, and protecting the eyes against dirty water etc. will all help to prevent against eye infections and the development of conjunctivitis,” Mabbott said

Bennett agreed: “It’s important people know when their risk of being exposed to the virus is on the rise so they can look out for symptoms and modify their risk of exposure, and of spreading the virus if they become infected. So letting people know conjunctivitis is a symptom to look out for is important, especially as for some people and children, this may be their only symptom.”

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