The study enrolled individuals who had been confirmed as infected with SARS-CoV-2 Omicron through nucleic acid amplification testing or rapid antigen testing between 1 December 2022 and 31 January 2023.

To ensure the reliability of the data, certain exclusion criteria were applied. Individuals who were unable to provide truthful information, those who omitted important details or exhibited clear logical errors regarding their gender, age, height, weight, or infection date, and those who submitted duplicate information were excluded from the study. The questionnaire survey was conducted nationwide from 19 January 2023, to 11 February 2023. Ethical considerations were strictly followed, in accordance with the Measures for the Ethical Review of Biomedical Research Involving Humans of the National Health Commission of the People’s Republic of China. The research protocol received ethical approval from the Eye and ENT Hospital Ethics Panel at Fudan University (Approval No. 2022127) for international data collection.

The questionnaire was collaboratively developed by two experienced doctors specializing in otolaryngology and public health. It consisted of eight sections, namely: informed consent, basic patient information, date of SARS-CoV-2 infection, ENT symptoms and outcomes, sleep quality, mental health status post-infection, pre-existing ENT medical history, and underlying medical conditions. In total, the questionnaire comprised 52 questions, utilizing formats such as single-choice, multiple-choice, and self-filling. For more detailed content of the questionnaire, please refer to the following link: [18] (Supplementary Material S1).

This study employed a cross-sectional research design and utilized convenience sampling to recruit participants. Data collection was carried out through self-administration of electronic questionnaires. We also made efforts to distribute the survey through various online platforms such as Weibo and WeChat. Within the questionnaire, all self-evaluated items concerning the impact of symptoms on daily life were rated on a scale of 0–10, with higher scores indicating a greater severity of impact.

The statistical analysis and data visualization were performed using R software version 4.2.2. Metric data that followed a normal distribution were presented as x ̃ ± s , while categorical variables were described as frequency (percentage), while categorical variables were reported as frequency (percentage). To compare the two groups, the chi-square test was employed for categorical data, and the Wilcoxon rank-sum test was used for ordinal data. A two-tailed p-value of less than 0.05 was considered statistically significant.

A total of 1,366 individuals participated in the questionnaire, out of which 433 (31.7%) resided in Shanghai, and 20 (1.5%) were located outside mainland China. The remaining participants were distributed across various provinces in China. Figure 1A illustrates the trend of newly infected cases investigated, demonstrating a rapid increase since December 1st, with a peak of 109 infections on 20th December. Subsequently, the number fluctuated and declined, with minimal newly identified cases reported after 15th January. It is worth noting that considering the presence of the incubation period and testing delays, the trend of newly infected individuals obtained from the investigation aligns with the changes in the nucleic acid detection rate reported by the CDC. This suggests a relatively high reliability of the investigation [2].

Among the 1,366 infected individuals, 1,071 (78.4%) were female. Common symptoms related to the nose and throat were observed, as the Omicron infection primarily affects the upper respiratory tract. Specifically, 1,054 (77.2%) individuals experienced some degree of nasal obstruction, and 1,015 (74.3%) reported rhinorrhea. In terms of otologic symptoms, tinnitus (29.7%) and vertigo (24.2%) were the most prevalent. It is worth noting that a minority of patients had a history of hypertension or diabetes, while 773 (56.6%) individuals had a history of ENT disease. Additional demographic data and the rates of symptomatic manifestations are provided in Table 1.

In terms of otologic symptoms, we observed a higher rate of symptoms among female individuals. This higher rate was particularly notable for symptoms such as stuffiness, earache, and vertigo. Additionally, females appeared to be at a greater risk in terms of the impact of otologic symptoms on their daily lives and the progression of symptoms.

When considering age groups, the rate of hearing loss symptoms increased with age, as shown in Table 2. The rate of tinnitus symptoms, on the other hand, was similar across all age groups, as depicted in Figure 1B. Earache and vertigo were more commonly observed in individuals over the age of 70. Among females in this age group, four individuals (80.0%) reported experiencing vertigo, whereas no males over 70 reported vertigo symptoms, as shown in Figure 1B.

Apart from the symptomatic rate, similar patterns were observed in terms of the impact on daily life and symptom progression. Overall, the impact of otologic symptoms on patients’ lives was relatively minor, but tinnitus had a more common and severe impact compared to other symptoms, as indicated in Table 2. Furthermore, earache and vertigo had a greater impact on females. A few patients sought medical attention after experiencing otologic symptoms related to COVID-19. In most cases, these symptoms improved or partially improved after treatment, while tinnitus and hearing loss were common residual symptoms, as depicted in Figures 2A, B.

The impact of BMI on otologic symptoms was found to be insignificant, with only a higher rate of ear pain observed in underweight individuals, as shown in Supplementary Table S1.

Nasal obstruction, rhinorrhea, and loss of smell had a significant impact on the daily lives of patients, as indicated in Table 3. Nearly half of the patients rated the impact of nasal symptoms as moderate to severe, with scores ranging from 4 to 10, as shown in Figure 2C. The symptomatic rate of rhinologic symptoms was generally higher among female cases, and these symptoms had a more severe impact and progression. Nasal obstruction, rhinorrhea, and other nasal symptoms were observed across all age groups, with a higher symptomatic rate among younger individuals. In fact, the symptomatic rate of nasal obstruction in children exceeded 90%, as depicted in Figure 1C. However, the impact and progression of symptoms were less severe compared to the middle-aged group.

Few patients sought treatment specifically for rhinologic symptoms. The results indicated a low short-term spontaneous recovery rate for the loss of sense of smell, but few patients reported residual symptoms, as shown in Figures 2C, D. The impact of BMI on rhinologic symptoms was found to be insignificant, as demonstrated in Supplementary Table S2. However, there was a trend of more severe progression of nasal obstruction in underweight individuals.

Throat symptoms were highly prevalent among individuals infected with SARS-CoV-2, with rates exceeding 80%. Similar to ear and nose symptoms, female individuals exhibited higher rates of symptomatic presentations, while no clear association was observed between age (Table 4) or BMI (Supplementary Table S3) and symptomatic rates.

Among the throat symptoms, cough was the most common, with a symptomatic rate of up to 100% in elderly patients, as shown in Figure 1D. Nearly 600 patients rated the impact of cough as severe, with scores ranging from 7 to 10. Furthermore, over 400 patients reported cough as a post-acute sequela of COVID-19 (Figures 2E, F). Additionally, females experienced more severe throat pain and poorer outcomes for all throat symptoms compared to males, as indicated in Table 4. Throat symptoms also exhibited higher rates of medical visits compared to ear or nose symptoms, as depicted in Figure 1.

Our investigation reveals an outbreak of COVID-19 infections in December 2022. We found that otologic symptoms have a relatively minor impact on patients’ lives. However, tinnitus and hearing loss are the most commonly reported residual symptoms. Rhinological symptoms have a relatively high symptomatic rate, but they typically do not persist as residual symptoms. On the other hand, laryngeal symptoms have the highest symptomatic rate and exert the greatest impact on patients’ quality of life. Furthermore, our study highlights that female patients are more vulnerable to these effects. These findings serve as a foundation for enhancing our understanding of the symptom spectrum in patients infected with the Omicron variant and provide valuable insights for targeted symptom management strategies.