Johnson & JohnsonIn Johnson & Johnson’s (NYSE:JNJ) Phase 3 trial for the Ad26.COV2.S COVID-19 vaccine, six vaccine recipients developed tinnitus or ringing in the ears.

In five of those individuals, tinnitus had either resolved or was resolving. The condition was unresolved in the other trial volunteer.

No placebo recipients developed the condition.

J&J concluded that the tinnitus reports were likely unrelated to the vaccine. The principal investigator in the trial that two of the events were related and the remainder unrelated.

A 21-year-old volunteer involved in an earlier clinical trial for the J&J vaccine developed tinnitus and sudden hearing loss 34 days after receiving the vaccine. The patient recovered 69 days after receiving the injection. Johnson & Johnson also determined that the event was unrelated to the vaccine.

In all, some 43,783 volunteers participated in the Phase 3 trial. A total of 19,630 participants received the Ad26.COV2.S vaccine. Only 0.03% of vaccine recipients reported tinnitus after inoculation, and those who did tended to have underlying medical conditions that are risk factors for the condition.

In a briefing document, FDA concluded that the data did not necessarily support a causal link between the tinnitus reports and the vaccine.

All six participants had at least one possible risk factor for tinnitus, including hypertension, hypothyroidism, depression, prior history of tinnitus, allergic rhinitis and medicine use.

Tinnitus events were not mentioned in FDA briefing documents on the vaccines from Moderna (NSDQ:MRNA) and Pfizer (NYSE:PFE) and BioNTech (NSDQ:BNTX).

COVID-19 itself could also induce or worsen tinnitus, according to a study published in Frontiers in Public Health.

An International Journal of Audiology study found that close to 15% of hospitalized COVID-19 patients reported hearing loss eight weeks after being discharged.

Tinnitus is often linked to hearing loss.

Stress associated with the pandemic could also exacerbate tinnitus.

Almost 50 million people in the U.S. have the condition, according to the American Tinnitus Association.