Oculo-respiratory syndrome

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Oculo-respiratory syndrome (ORS) is a short-lived reaction that can occur after an influenza vaccine. It causes red, itchy or inflamed eyes on both sides, facial swelling, and/or upper respiratory symptoms. Symptoms usually start 2–24 hours after vaccination and typically go away within 2–3 days. If you experience any combination of these symptoms after a flu shot, ask a general practitioner about possible vaccine side effects.

ORS first appeared in the 2000–2001 flu season in Canada due to a manufacturing error in the trivalent influenza vaccine. It is very rare and mostly affected middle-aged white women in Canada; the exact cause is not known.

Most people recover with simple relief, such as over-the-counter pain relievers and cough medicines. Hospitalizations are rare and have mainly involved older people.

If you get another flu shot, the chance of ORS coming back is higher, but the symptoms are usually milder the next time. People aged 60 and older may be more likely to see recurrence.

There was a similar issue in Europe in the 1990s, but it was not ORS. Some COVID-19 vaccines have been linked to eye problems like eye inflammation or optic neuritis, but these are not proven to be ORS; research is ongoing.