NEW YORK (Reuters Health) - Two new studies provide somewhat conflicting data on the risk of sudden sensorineural hearing loss after COVID-19 vaccination. One found no link and the other found a marginally elevated risk after the Pfizer/BioNTech vaccine.
"Together, these two studies, involving almost 200 million COVID-19 vaccine doses, suggest that further investigation of the potential association between COVID-19 vaccination and sudden sensorineural hearing loss may be warranted," write the authors of an editorial published with the studies in JAMA Otolaryngology - Head & Neck Surgery.
However, Dr. Angela K. Ulrich of the University of Minnesota, in Minneapolis, and co-authors, say the data "must be weighed alongside the known risks of COVID-19, including COVID-19-associated sudden sensorineural hearing loss, and the many reported benefits of COVID-19 vaccination."
In one study, Dr. Eric Formeister of Johns Hopkins University in Baltimore, Maryland, and colleagues investigated reports of sudden sensorineural hearing loss (SSNHL) after COVID-19 vaccination reported to the Centers for Disease Control and Prevention Vaccine Adverse Events Reporting System (VAERS).
During the first seven months of the U.S. COVID vaccine rollout (mid-December 2020 to mid-July 2021), 185.4 million doses of COVID-19 vaccine were administered in the U.S. and 555 VAERS reports met the definition for probable SSNHL.
The annual incidence of SSNHL ranged from 0.6 to 28.0 cases per 100,000 people, with no significant difference among the three vaccines.
"Our analysis found that, based on VAERS reports, the estimated incidence of SSNHL after COVID-19 vaccination did not exceed the reported incidence of idiopathic SSNHL in the general population," report Dr. Formeister and colleagues.
They note that while they could not identify any "population-level" association between COVID-19 vaccination and SSNHL, "an association among some individuals cannot be excluded without further research."
In the other study, researchers in Israel examined SSNHL cases among 2.6 million members of Clalit Health Services who received a first dose of the Pfizer COVID-19 vaccine, and 2.4 million members who received a second dose.
SSNHL after vaccination was diagnosed in 91 patients within 21 days after the first dose and 79 patients after the second dose, report Dr. Yoav Yanir with Lady Davis Carmel Medical Center in Haifa and colleagues.
The incidence rate (per 100,000 person-years) of SSNHL was 60.77 after the first dose and 56.24 after the second dose. This compares to SSNHL incidence rates of 41.50 in 2018 and 44.46 in 2019.
These rates correspond to an age- and sex-weighted standardized incidence ratio of 1.35 (95% CI,1.09 to 1.65) after the first dose and 1.23 (95% CI, 0.98 to 1.53) after the second dose compared with expected cases of SSNHL estimated from rates among the Clalit Health Services population in 2018 and 2019, the authors say.
While the findings hint at a link between the Pfizer COVID-19 vaccine and SSNHL, the effect size is "very small," Dr. Yanir and colleagues point out.
"Considering these findings along with the good prognosis for patients with SSNHL, we suggest that the benefits of the (Pfizer) COVID-19 vaccine outweigh its potential association with SSNHL," they conclude.
The editorialists agree.
"COVID-19 vaccines are highly successful in preventing SARS-CoV-2 infection and in turn reducing the risk of transmitting the virus to others. The many benefits of COVID-19 vaccines substantially outweigh the rare risks associated with vaccination," write Dr. Ulrich and co-authors.
"COVID-19 vaccines," they add, "have undergone, and will continue to undergo, extensive safety monitoring by the Food and Drug Administration and the Centers for Disease Control and Prevention in the U.S. and by other national and international monitoring bodies in other countries. In clinical trials and post-market surveillance, COVID-19 vaccines have been found to be safe. Ongoing surveillance to detect rare adverse events after vaccination is important to ensuring the safety of these vaccines and engendering the public's trust."
SOURCE: https://bit.ly/3IrHOcP, https://bit.ly/3Iriovz and https://bit.ly/3K519kp JAMA Otolaryngology-Head & Neck Surgery, online February 24, 2022.
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