Covid-19 variant symptoms
Pro Research Analysisby 
Searched over 200M research papers
COVID-19 Variant Symptoms: Differences Across Strains
Symptom Profiles by Variant: Wild-Type, Alpha, Delta, and Omicron
Research shows that the symptoms of COVID-19 can vary depending on the specific variant of the virus. For example, patients infected with the original Wuhan (wild-type) strain often experienced more symptoms at the time of hospital admission, such as fever, shortness of breath (dyspnea), and gastrointestinal issues, compared to those infected with Alpha or Delta variants. The Delta variant, on the other hand, was more likely to cause headache, loss of smell (anosmia), and loss of taste (ageusia) as initial symptoms. After recovery, people who had the Wuhan variant reported more lingering symptoms, especially ongoing shortness of breath, while hair loss was more common after Delta infection. Fatigue was a common long-term symptom across all variants, regardless of which strain caused the infection Fernández‐de‐las‐Peñas2022Canas2023.
Omicron Variant: Milder and Different Symptom Patterns
The Omicron variant has been associated with a milder disease course compared to earlier variants. Many Omicron cases are asymptomatic, but when symptoms do occur, they most commonly include cough, fever, fatigue, and expectoration (coughing up phlegm). Notably, cold-like symptoms such as runny nose, headache, and fatigue are frequently reported with Omicron, and loss of smell or taste is much less common than with previous variants Abe2023Zhang2022Iacobucci2021. Respiratory symptoms, such as cough and shortness of breath, are more frequent in Omicron infections compared to the wild-type strain, but persistent loss of smell or taste is significantly less likely .
Predictors of Severe Disease and Pneumonia in Omicron
Certain symptoms can help predict the risk of developing pneumonia in patients with Omicron. These include expectoration, shortness of breath, difficulty breathing, and having symptoms that last more than seven days. Shortness of breath and difficulty breathing are especially important as early warning signs for pneumonia in Omicron cases .
Changes in Symptom Order and Presentation
The order in which symptoms appear can also change with different variants. For example, with the D614G variant (which became dominant in the USA), cough was more likely to appear before fever, while the original Wuhan strain typically caused fever before cough. This shift in symptom order may have contributed to increased transmission, as people with the D614G variant were more likely to cough in public before feeling too ill to go out .
Long COVID and Post-COVID-19 Symptoms by Variant
Long-term symptoms after COVID-19, known as post-COVID-19 condition or "long COVID," can also differ by variant. Across all variants, clusters of symptoms have been identified, including cardiorespiratory (heart and lung), neurological (brain and nerves), and multi-organ inflammatory symptoms. The specific combination and duration of these symptoms can vary depending on the variant and whether the person was vaccinated . Cognitive symptoms such as memory problems and "brain fog" have been reported, with more severe cognitive deficits seen in people infected with the original virus or the Alpha variant compared to later variants like Omicron .
General Symptom Trends Across Variants
Despite these differences, some symptoms remain common across all COVID-19 variants. Upper respiratory symptoms (such as cough and sore throat), fever, and changes in taste or smell are frequent, though the likelihood of each can shift with new variants. Extrapulmonary complications—affecting the heart, brain, gut, and skin—can occur with any variant, especially in severe cases or those with underlying health conditions .
Conclusion
COVID-19 symptoms can vary significantly depending on the variant of the virus. While early strains like the Wuhan variant caused more severe and diverse symptoms, newer variants such as Omicron tend to produce milder, more cold-like symptoms, with less frequent loss of smell or taste. The risk of severe disease and the pattern of long-term symptoms also differ by variant. Understanding these differences helps guide diagnosis, treatment, and public health responses as the virus continues to evolve Abe2023Liao2024Larsen2021+6 MORE.
Sources and full results
Most relevant research papers on this topic