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Sore throat the most common Covid-19 symptom in Sri Lankans: Study 

28 Apr 2022

 
  • Over 50% of patients completely asymptomatic 
  • Possibility of reduced viral clearance with HCQ among asymptomatics
  BY Ruwan Laknath Jayakody Sri Lankan patients with Covid-19 have different clinical characteristics and while a sore throat was the most common symptom, more than half of the patients were completely asymptomatic and a majority of the latter remained asymptomatic at the time of admission (true asymptomatic), thus causing no significant morbidity or mortality, a local study found.  Furthermore, the large proportion of asymptomatic cases indicates the difficulty in identifying patients with Covid-19 without intensive contact tracing and screening. Also, 13.4% of patients who had not had a contact history getting the illness may indicate the possibility of community transmission.  These findings and observations were made in a research on the “Clinical and epidemiological characteristics and outcome of patients with Covid-19 in Sri Lanka: An observational study” authored by a group of Consultant Physicians and published in the Asian Journal of Internal Medicine 1 (1) in January 2022.  In Sri Lanka, at the time of the study, according to the Ceylon College of Physicians and the Health Ministry’s Epidemiology Unit’s “Provisional clinical guidelines on Covid-19 suspected and confirmed patients”, diagnosed patients were managed per the local guidelines in designated treatment hospitals for Covid-19, where the positive patients admitted to dedicated Covid-19 hospitals were kept under strict observation till their recovery and confirmation of virus-negative status.  Jayasekera et al. sought to evaluate the clinical and epidemiological characteristics, the laboratory investigations, management including treatment with Hydroxychloroquine (HCQ) and the outcomes of patients with Covid-19 who were admitted to six treatment centres in Sri Lanka.  For the specific epidemic situation of Covid-19, Jayasekera et al. chose to conduct a descriptive, retrospective study at six treatment centres, namely the Welikanda Base Hospital, the Mulleriyawa Base Hospital, the Iranawila Covid-19 treatment centre, the Kattankudy Base Hospital, the Homagama Base Hospital and the Welisara Navy General Hospital. Data was extracted from the patients’ notes and medical records.  All the patients with laboratory confirmed Covid-19 who were admitted to the six above-mentioned treatment centres between 10 March 2020 and 30 May 2020, were recruited to the study. All patients (symptomatic as well as asymptomatic) admitted to these six treatment centres were kept under close medical observation till they became asymptomatic and two consecutive polymerase chain reaction (PCR) tests became negative. A confirmed Covid-19 patient is defined as a positive result on a high throughput sequencing or real time reverse transcriptase PCR assay of nasal and pharyngeal swab specimens.  A total of 431 PCR-positive Covid-19 subjects were studied. Of them, 335/78% were males. The mean (average) age was 37.1 years, with the mean age for males being 35 years and the mean age of females being 45 years. Of this cohort, a majority (292) were Sinhalese, followed by Muslims (116), and Tamils (23). Half of the patients (219 – 50.81%) were Navy personnel while only two Police personnel and one Army personnel were present.  Most patients (373 – 86.5%) had had close contact with Covid-19-positive patients. Of them, 226/52.4% patients declared their close contacts as occurring in their workplaces. A total of 14/3.2% patients had been exposed to overseas returnees and only three patients had contracted the virus at the airport. There were 35/8.1% patients with a positive history of overseas travel within the previous three months before they got infected. A total of 73/16.9% patients were identified during contact tracing and there was no obvious known contact history in 58/13.4% patients.  There were only 89/20.6% patients with comorbidities. The most common comorbidity was hypertension (43 - 9.9%), followed by diabetes (31 – 7.1%) and dyslipidaemia (abnormal amount of lipids in the blood) (14 – 3.2%). There were 271 smokers.  On admission, the majority were asymptomatic (344 – 80%) with only 20% having symptoms either before or on admission. During the period of medical observation in the hospital, another 101/23.4% patients developed symptoms. Among the symptomatic patients, the most common presenting symptom was sore throat (81 – 19%), followed by cough (72 – 17%), headache (72 – 17%), fever (50 – 12%) and nasal discharge (36 – 8%). Only 10/2% had anosmia (partial or full loss of smell). A total of 7/1.6% patients had dyspnoea on admission while another 15/3.5% developed dyspnoea during the hospital stay. Only five patients developed hypoxia (low oxygen in the tissues) during their hospital stay and needed oxygen therapy.  Out of 431 patients, only three patients required high dependency care while five required intensive care. A total of two patients died due to pneumonia complicated with acute respiratory distress syndrome. A total of eight patients were transferred to the National Institute of Infectious Diseases Hospital.  Patients treated with HCQ (248) had significantly longer (17.6 days) durations of hospital stay compared to patients (113) not treated (13.6 days) with HCQ. In the group treated with HCQ, both asymptomatic and symptomatic patients had similar durations of hospital stay while in the group not treated with HCQ, asymptomatic individuals had a significantly shorter duration of hospital (11.1 days) stay compared to  symptomatic individuals (14.3).  As noted in “Social distancing alters the clinical course of Covid-19 in young adults: A comparative cohort study” by M. Bielecki, R. Züst, D. Siegrist, D. Meyerhofer, G.A.G. Crameri, Z. Stanga, A. Stettbacher, T.W. Buehrer and J.W. Deuel, owing to strict measures such as lockdowns, the closure of schools and non-essential workplaces, bans on social gatherings, severe travel restrictions, and island-wide curfews, the pattern and clinical characteristics of Covid-19 in Sri Lanka may have taken a different shape.  Most of the patients in the study were recognised when they were asymptomatic, during the process of contact tracing and screening. All the positive patients were hospitalised and the majority (54%) of them remained asymptomatic during the course of the illness. There was a higher proportion of asymptomatic patients in the study. The most common symptom in the study was sore throat (19%) followed by cough (17%), and headache (17%). Another finding was the absence of fever in the majority (88%) of our patients (376 out of 431). A runny nose was a comparatively rare symptom (8%) in this study.  “There are a number of possible reasons for the contrasting pattern of symptomatology in this study. One explanation could be the patients’ characteristics such as age. In the study, the mean age was 37 years with nearly 50% being otherwise healthy and physically fit Navy personnel. These young and healthy individuals are more likely to develop asymptomatic infection with less prominent symptoms than older individuals, per a Chinese study and a Japanese study. Intensive contact tracing and screening helped in recognising more patients with asymptomatic illnesses in the study. Other possibilities include a less virulent viral strain causing Covid-19 in Sri Lanka, the effect of geographical factors such as higher temperatures and the prevention of repeated exposure to the virus via intensive screening and isolation.”  “Health systems in most countries actively discourage individuals with no or mild symptoms from admitting themselves into a hospital.” However, as all individuals found positive for Covid-19 were admitted to hospitals in Sri Lanka (regardless of symptoms) at the time of the study, Jayasekera et al. were able to retrospectively observe the clinical course of asymptomatic patients with Covid-19. In this study, 20% (87 out of 431) had symptoms at the time of admission and another 23% (101 out of 431) subsequently developed symptoms (pre-symptomatic illness). More than half (56%, 243 out of 431) remained asymptomatic during the extended period of close medical observation, and never exhibited any symptoms. Of the patients who became symptomatic during their hospital stay, the most common symptoms were sore throat (9.5%), and headache (8%) followed by cough (7.6%) and fever (5.3%). However, Jayasekera et al. pointed out that this figure is clearly an underestimation since testing had primarily occurred only among individuals who had symptoms.  In this study, the mean age was 37 years. Younger subjects and a significantly lower number of patients with comorbidities would be, according to “Association between age and clinical characteristics and outcomes of Covid-19” by Y. Liu, B. Mao, S. Liang, J.W. Yang, H.W. Lu, Y.H. Chai, L. Wang, L. Zhang, Q.H. Li, L. Zhao, Y. He, X.L. Gu, X.B. Ji, L. Li, Z.J. Jie, Q. Li, X.Y. Li, H.Z. Lu, W.H. Zhang, Y.L. Song, J.M. Qu and J.F. Xu, the likely reasons for the higher prevalence of asymptomatic infection in the present study. The study also showed a true asymptomatic rate of 71% (244 out of 345) among 345 asymptomatic individuals on admission. Based on the results, Jayasekera et al. concluded that around 70% of asymptomatic individuals with Covid-19 do not develop any symptoms.  Another finding observed in the study was the negative effect of HCQ on the duration of Covid-19 positivity and thereby the duration of hospital stay. The study revealed that those who were treated with HCQ had significantly longer (17.6 days) durations of hospital stay compared to those who were not treated (13.6 days) with HCQ.  Furthermore, both asymptomatic and symptomatic patients treated with HCQ had similar and longer durations of hospital stay than the patients not treated with HCQ. When HCQ was not used for treatment, asymptomatic individuals had significantly shorter durations of hospital stay (11.1 days) compared to symptomatic individuals (14.3 days). According to Jayasekera et al., this finding possibly indicates that HCQ might lead to reduced viral clearance, preferentially among asymptomatic individuals, thus prolonging the duration of Covid-19 positivity. The study also indicated the possibility of reduced viral clearance with HCQ in vivo (in a living organism) among asymptomatic individuals with Covid-19.


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