Shedding Light on SARS-CoV-2, COVID-19, COVID-19 Vaccination, and Auditory Symptoms: Causality or Spurious Conjunction?

Abstract

There are reports of associations between SARS-CoV2, COVID-19, COVID-19 vaccines, and auditory symptoms (hearing difficulty, tinnitus). However, most studies have relied on self-report and lack baseline and/or non-COVID control groups. This makes it problematic to differentiate if symptoms are associated with SARS-CoV2, COVID-19, the vaccine, psychosocial factors or recall bias. In this study, we differentiate these by comparing hearing and tinnitus survey data collected pre- and during the pandemic. The survey conducted during the pandemic asked about the onset and change in three types of symptom. Type One—known association (loss of smell, memory/concentration issues, persistent fatigue), Type Two—indeterminate association (auditory symptoms), and Type Three—no established association with COVID-19 (toothache). We hypothesized that if auditory symptoms are directly associated with COVID-19, their onset and change would be similar to Type One symptoms, but if indirectly associated (reflecting psychosocial factors and/or recall bias) would be more similar to Type Three symptoms. Of the 6,881 individuals who responded, 6% reported confirmed COVID-19 (positive test), 11% probably had COVID-19, and 83% reported no COVID-19. Those with confirmed or probable COVID-19 more commonly reported new and/or worsened auditory symptoms than those not reporting COVID-19. However, this does not imply causality because: (1) new auditory symptoms coincided with COVID-19 illness among just 1/3 of those with confirmed or probable COVID-19, and another 1/3 said their symptoms started before the pandemic—despite reporting no symptoms in the pre-pandemic survey. (2) >60% of individuals who had COVID-19 said it had affected their Type 3 symptoms, despite a lack of evidence linking the two. (3) Those with confirmed COVID-19 reported more Type 1 symptoms, but reporting of Type 2 and Type 3 symptoms did not differ between those with confirmed COVID-19 and those without COVID-19, while those who probably had COVID-19 most commonly reported these symptom types. Despite more reports of auditory symptoms in confirmed or probable COVID-19, there is inconsistent reporting, recall bias, and possible nocebo effects. Studies that include appropriate control groups and use audiometric measures in addition to self-report to investigate change in auditory symptoms relative to pre-COVID-19 are urgently needed.

Long-Term Effects of COVID-19 and the Pandemic on Tinnitus Patients

“…We found that in patients who have contracted COVID-19, tinnitus loudness and THI score increased significantly ( Table 3 ). Our findings agree with Saunders et al, who also observed worsening tinnitus complaints in 23.1% of patients with preexisting tinnitus who contracted COVID-19 ( 12 ). However, in addition to the open question also used by Saunders et al, we used a validated instrument to measure the degree of tinnitus complaints and compared the values to the pre-pandemic ones.…”

“…Although the scores indicating tinnitus annoyance, tinnitus effect on life, tinnitus effect on sleep, and HQ scores were higher after COVID-19, the differences before-after were not statistically significant. Additionally, as stated in the current literature, the relationship between COVID-19 and the onset of auditory symptoms or worsening of the preexisting ones might depend on the negative effects of the pandemic process and, therefore, should be established with care ( 12 , 43 ).…”

“…In a large UK-based survey-based study that enclosed 6,881 subjects with a sub-sample of 1,274 individuals who had tinnitus prior to the pandemic, tinnitus worsened significantly more in those who contracted COVID-19 than in the non-infected ones. However, caution was advised when establishing a relationship between auditory symptoms and COVID-19 based on self-reported data ( 12 ).…”

Sudden Sensorineural Hearing Loss in the COVID-19 Pandemic: A Systematic Review and Meta-Analysis

“…On the other hand, the use of ototoxic medications, such as chloroquine, in some COVID-19 patients may have acted as a confounding factor, making an accurate differentiation between ototoxicity and an actual virus-related SSNHL hard to achieve [ 44 ]. However, the consistency of the hypotheses around the causative link between COVID-19 and audiovestibular symptoms may be affected by possible biases resulting from the symptom reporting methods employed in the published studies, as suggested by Saunders et al [ 45 ]. In fact, the nocebo effect might have led some COVID-19 patients to complain, for the first time during the infection period, about symptoms they had experienced before.…”

Is COVID‐19 to Blame for Sensorineural Hearing Deterioration? A Pre/Post COVID‐19 Hearing Evaluation Study

“…The authors concluded that the subjective participant reports were inconsistent, included possible recall bias, and may have been biased due to a nocebo effect. 15 Thus, the limitations of case, case–control, and subjective studies have raised the need for additional audiological measurements and comparisons among COVID‐19 patients to further investigate the possible effect of the infection on the hearing system.…”