A new idea has been put forward by research teams such as the Department of Twin Research and Genetic Epidemiology at King’s College London and the National Institutes of Health (NIHR) Biomedical Research Centre: Genetic factors play a part in the observed individual differences in the main symptoms of COVID-19.
The research team published the study online on the preprinted website medRxiv, “Self-report symptoms of covid-19 symptoms most most must of the SARS-CoV-2 infection, are heritable”, which has not yet been peer-reviewed.
The team developed a symptom-tracking app (C-19 Covid Symptom Tracker app, https://doi.org/10.1101/2020.04.02.20051334) to collect real-time data during the SARS-CoV-2 pandemic. The app, which has been downloaded by 2 million people, asks users every day if they have some common symptoms, including coughing, fever, chest pain, delirium and loss of sense of smell.
Infectious diseases may exhibit a hereditary nature, namely, infection and developmental tendencies, as well as the severity of the immune response, which are influenced by host genetic factors, the paper said. Similar findings have been found in previous studies on H1NI infections. Therefore, the team hypothesized that the host genotype may affect susceptibility to infections such as SARS-CoV-2.
The team included adult twins who reported their current symptoms in the early-started TwinsUK project. Between 25 March and 3 April 2020, data were provided on 2,633 adult same-sex twins. The study used a classic twin study of COVID-19 symptoms based on symptom-based machine learning algorithms and predicted the likelihood of infection in individuals.
The analysis consisted of 728 complete pairs, of which 537 were identical twins (MZ), 191 were fraternal twins (DZ), and 86.9% were women.
The results showed that the correlation between COVID-19 symptoms and genetics was: delirium , 49% (95% confidence interval, 24%-75%), fever , 41% (95% confidence interval, 12%-70%), weakness , 32% (95% confidence interval, 1%-64%), sense of smell loss , 47% (95% confidence interval, 27%-67%), shortness of breath ( 43% (95% confidence interval, 8%-77%), and diarrhea – 34% (95% confidence interval, 14% -55%)。
But hoarse voice, cough, loss of appetite, chest pain, abdominal pain are determined by environmental factors.
The team also received real-time information about their current co-residents via text message. To control the effects of intra-family infections, they repeated similar studies on twins living separately.
The results were similar in that the correlation between COVID-19 symptoms and genetics was a decrease in fever of 41% (7%-74%), loss of sense of smell for 48% (25%-72%), shortness of breath for 47% (12%-82%), but increased diarrhea (41%), delirium (37%) and fatigue (24%).
Genetic correlation was also observed in the “prediction coVID-19” area: 50% (29-70%) were in the overall sample, while the near-separatetwin sample showed 54% (30-77%). The “predictive COVID-19” state is determined by a linear combination of self-reported age, sex, loss of sense of smell, severe or apparent persistent coughing, fatigue, and loss of appetite.
The study noted that symptoms associated with immunoactivation, such as fever, delirium and fatigue, were more than 35 percent more likely to be genetically active. Their previous study, which found that loss of smell was an important predictive symptom of COVID-19, showed a genetic probability of 48 percent.
They believe that SARS-CoV-2 infection is not a purely random event, but is influenced to some extent by host genetics and may reflect differences in the host’s immune response.
The team analyzed that viral infections often lead to T-cell activation, and influenza-like symptoms such as fever caused by IL-1, IL-6, and TNF-alpha inflammatory media. This genetic-based response difference will provide important clues to treatment and help identify groups with a high risk of death, which tends to experience cytokine storms 1-2 weeks after symptoms appear.
Notably, the team also noted that subsequent nucleic acid tests by APP users (n-5238) proved that their model was already the best model for predicting THE SARS-CoV-2 positive.
The team concluded that the purpose of the study was to assess the hereditability of COVID-19 symptoms and to identify phenotypes suitable for genome-wide association studies. Public health measures to identify people at increased genetic risk of serious infections would be useful in reducing the economic impact of closures and social alienation policies.