Persistent cough and fever have been confirmed as the most prevalent symptoms associated with COVID-19, according to a major review of the scientific literature. Other major symptoms include fatigue, losing the ability to smell and difficulty in breathing. The study ratifies the list of symptoms compiled by the World Health Organisation at the start of the pandemic.
The researchers – from University of Leeds and four other universities – combined data from 148 separate studies to identify the common symptoms experienced by more than 24,000 patients from nine countries including the UK, China and the US.
The study is one of the biggest reviews or meta-analysis ever conducted into COVID-19 symptoms.
Of the 24,410 cases, the study found: 78% had a fever. Although this tended to vary across countries, with 72% of fever reported by patients in Singapore and 32% in Korea; 57% reported a cough. Again, this varied across countries, with 76% of patients reporting a cough in the Netherlands compared to 18% in Korea; 31% said they had suffered fatigue; 25% lost the ability to smell; and 23% reported difficulty breathing.
The researchers believe the variation in the prevalence of symptoms between countries is due, in part, to the way data was collected.
Of those patients who needed hospital treatment, 17% needed non-invasive help with their breathing; 19% had to be looked after in an intensive care unit; 9% required invasive ventilation; and 2% needed extra-corporeal membrane oxygenation (an artificial lung).
Ryckie Wade, a surgeon and clinical research fellow at the Leeds Institute of Medical Research, supervised the research. He said: "This analysis confirms that a cough and fever were the most common symptoms in people who tested positive with COVID-19. "This is important because it ensures that people who are symptomatic can be quarantined, so they are not infecting others. The study gives confidence to the fact that we have been right in identifying the main symptoms and it can help determine who should get tested."
The researchers acknowledge there are people who had the virus but did not display any symptoms.
The study involved academics from the University of Leeds with colleagues from the University of Sheffield, University of Bristol, Imperial College London, and the Belgium Cancer Centre. The research was funded by the UK's National Institute for Health Research and VALCOR, in Belgium.
Background: To limit the spread of SARS-CoV-2, an evidence-based understanding of the symptoms is critical to inform guidelines for quarantining and testing. The most common features are purported to be fever and a new persistent cough, although the global prevalence of these symptoms remains unclear. The aim of this systematic review is to determine the prevalence of symptoms associated with COVID-19 worldwide.
Methods: We searched PubMed, Embase, CINAHL, AMED, medRxiv and bioRxiv on 5th April 2020 for studies of adults (>16 years) with laboratory test confirmed COVID-19. No language or publication status restrictions were applied. Data were independently extracted by two review authors into standardised forms. All datapoints were independently checked by three other review authors. A random-effects model for pooling of binomial data was applied to estimate the prevalence of symptoms, subgrouping estimates by country. I2 was used to assess inter-study heterogeneity.
Results: Of 851 unique citations, 148 articles were included which comprised 24,410 adults with confirmed COVID-19 from 9 countries. The most prevalent symptoms were fever (78% [95% CI 75%-81%]; 138 studies, 21,701 patients; I2 94%), a cough (57% [95% CI 54%-60%]; 138 studies, 21,682 patients; I2 94%) and fatigue (31% [95% CI 27%-35%]; 78 studies, 13,385 patients; I2 95%). Overall, 19% of hospitalised patients required non-invasive ventilation (44 studies, 6,513 patients), 17% required intensive care (33 studies, 7504 patients), 9% required invasive ventilation (45 studies, 6933 patients) and 2% required extra-corporeal membrane oxygenation (12 studies, 1,486 patients). The mortality rate was 7% (73 studies, 10,402 patients).
Conclusions: We confirm that fever and cough are the most prevalent symptoms of adults infected by SARS-CoV-2. However, there is a large proportion of infected adults which symptoms-alone do not identify.
Michael C Grant, Luke Geoghegan, Marc Arbyn, Zakaria Mohammed, Luke McGuinness, Emily L Clarke, Ryckie G Wade
Leeds University material
PLOS One abstract