Prevalence and risk factors of long COVID 6-12 months after infection with the Omicron variant among nonhospitalized patients in Hong Kong.

Long COVID has been reported among patients with COVID-19, but little is known about the prevalence and risk factors associated with long COVID 6-12 months after infection with the Omicron variant. This is a large-scale retrospective study. A total of 6242 out of 12 950 nonhospitalized subjects of all ages with SARS-CoV-2 infection (confirmed by polymerase chain reaction/rapid antigen test) during the Omicron dominant outbreak (December 31, 2021-May 6, 2022) in Hong Kong were included. Prevalence of long COVID, frequencies of symptoms, and risk factors were analyzed. Three thousand four hundred and thirty (55.0%) subjects reported at least one long COVID symptom. The most reported symptom was fatigue (1241, 36.2%). Female gender, middle age, obesity, comorbidities, vaccination after infection, having more symptoms, and presenting fatigue/chest tightness/headache/diarrhea in the acute stage of illness were identified as associated risk factors for long COVID. Patients who had received three or more doses of vaccine were not associated with a lower risk of long COVID (adjusted odds ratio 1.105, 95% confidence interval 0.985-1.239, p = 0.088). Among patients with at least three doses of vaccine, there was no significant difference in the risk of long COVID between the CoronaVac vaccine and BNT162b2 vaccine (p > 0.05). Omicron infection can lead to long COVID in a significant proportion of nonhospitalized patients 6-12 months after infection. Further investigation is needed to uncover the mechanisms underlying the development of long COVID and determine the impact of various risk factors such as vaccines.

Weekly symptom profiles of nonhospitalized individuals infected with SARS-CoV-2 during the Omicron outbreak in Hong Kong: A retrospective observational study from a telemedicine center.

Omicron BA.2.2 is the dominant variant in the Hong Kong outbreak since December 31, 2021. There is no study reporting the weekly symptom profile after infection. In this retrospective study, participants who tested positive for SARS-CoV-2 after December 31, 2021, and registered in the telemedicine system between March 14 and May 6, 2022, were analyzed. Among registered 12 950 self-quarantined COVID-19-positive patients, 11 776 symptomatic patients were included for weekly symptom profile analysis. A total of 4718 (40.1%) patients reported symptoms in the first week after a positive test, 2501 (21.2%) in the second week, 1498 (12.7%) in the third week, 1048 (8.9%) in the fourth week, and 2011 (17.1%) in over 4 weeks. Cough was the most common symptom in all participants. Patients in the first week had higher odds of reporting fever (0.206, 95% confidence interval [CI]: 0.161-0.263, p < 0.001) and sore throat (0.228, 95% CI: 0.208-0.252, p < 0.001). Patients in over 4 weeks had higher odds of reporting fatigue (1.263, 95% CI: 1.139-1.402, p < 0.001). Further, having at least two vaccine doses linked to lower odds of having fever (0.675, 95% CI: 0.562-0.811, p < 0.001), but not associated with the presence of cough and fatigue. Diabetic patients had higher odds of reporting diarrhea (1.637, 95% CI: 1.351-1.982, p < 0.001). Symptoms from Omicron infection may last for more than 4 weeks and symptom profiles vary from week to week. Vaccination and comorbidity affect the symptom profiles.

Effectiveness of Chinese Herbal Medicine in Patients with COVID-19 During the Omicron Wave in Hong Kong: A Retrospective Case-Controlled Study.

SARS-CoV-2 Omicron led to the most serious outbreak of COVID-19 in Hong Kong in 2022. Under the pressure of a high volume of patients and limited medical resources, Chinese herbal medicine (CHM) has been extensively used. This is a case-control study of the infected patients that aims to evaluate the effectiveness of CHM using data extracted from the Hong Kong Baptist University Telemedicine Chinese Medicine Centre database. Patients with COVID-19 confirmed by either a rapid antigen test or a polymerase chain reaction who had completed two consultations and taken CHM within 10 days of the first positive test were included in the study (CHM group, [Formula: see text]). The matched control cases were those who did not take CHM within 10 days of the first positive test and were based on age ([Formula: see text] 3 years), vaccine doses ([Formula: see text] 3 doses, or 3 doses), and gender (no-CHM group, [Formula: see text]). The outcomes included the negative conversion time (NCT, primary outcome), total score of individual symptoms, number of the reported symptoms, and individual symptom disappearance rates. The NCT of the CHM group (median days: 7.0, interquartile range: 6.0-8.0) was significantly shorter than that of the no-CHM group (8.0, 7.0-10.5; [Formula: see text]). CHM treatment significantly reduced the total score of individual symptoms ([Formula: see text]) and the number of the reported symptoms ([Formula: see text]) as compared with that of the no-CHM group. Additionally, the symptom disappearance rates of symptoms such as chills, cough, sputum, dry throat, itching throat, headache, chest tightness, abdominal pain, diarrhea, and fatigue were significantly higher in the CHM group than in the no-CHM group. In conclusion, CHM intervention can significantly reduce NCT and COVID-19 symptoms. Chinese medicine can be accurately prescribed based on a telemedical consultation.

Detecting violation in abstract pitch patterns with mismatch negativity.

The human brain automatically extracts regularities embedded in environmental auditory events. This study investigated the extraction of abstract patterns by measuring mismatch negativity (MMN). Participants watched a silent subtitled movie and ignored a sequence of auditory events comprising frequent standards and rare deviants presented in the background. Tone triplets with varying pitch (first-order property) served as the auditory events. The pitch intervals (interval 1 and interval 2) between the tones in a triplet and the ratio of interval 1 and 2 were considered second- and third-order properties, respectively. Both second- and third-order properties of the standards were kept constant in the mixed patterns block, while only the third-order property was kept constant in the ratio pattern block. Four sets of tone triplets violating the interval and ratio patterns with different deviance levels were presented as deviants in both blocks, and subtracted with physically identical stimuli in a control block to isolate the MMNs. Interval and ratio pattern deviants elicited MMNs in the mixed patterns block while only ratio pattern deviants elicited MMNs in the ratio pattern block. Larger MMNs were elicited by large deviants as compared to small deviants. These results suggest that the change detection system is sensitive to the violation of both second- and third-order abstract patterns. In addition to regularities in the abstract properties of auditory events, regularities in the relationships between abstract properties can also be extracted. This ability plays an important role in music and language perception.