Early signs of the Delta variant often resembled a common cold, including runny nose, sore throat, headache, and fever, differing from earlier strains where loss of taste/smell was prominent; these symptoms could be mild, like a cold, but still indicated COVID-19, emphasizing testing even with seemingly minor issues.
What are the symptoms of the Delta variant?
Common New COVID Variant Symptoms in 2025
While an increase in infections alone is troubling and can lead to more deaths—both through the increase in cases and by overwhelming the health system—early research suggests Delta is possibly more dangerous than the Alpha variant and twice as likely to lead to hospitalization.
Omicron vs. Delta symptoms differ in several ways. While Delta variant symptoms include a loss of taste and smell and a persistent cough, Omicron symptoms are more likely to have a sore throat, a runny nose and sneezing.
A global meta-analysis published yesterday in the International Journal of Infectious Diseases estimates that the deadliest SARS-CoV-2 variant of concern (VOC) was Beta, followed by Gamma, Alpha, Delta, and Omicron, with variant-specific case-fatality rates (CFRs) ranging from 0.7% to 4.2%.
The Delta variant has mutations in the gene encoding the SARS-CoV-2 spike protein causing the substitutions D614G, T478K, P681R and L452R. It is identified as the 21A, 21I, and 21J clades under the Nextstrain phylogenetic classification system.
The two best ways to protect yourself against the delta variant
The Delta variant of SARS-CoV-2, first identified in India in October 2020 (1), became the dominant variant in >130 countries worldwide during June–November 2021 (2).
The COVID-19 incubation period typically ranges from 2- 14 days but averages 3-5 days. COVID is most contagious from two days before to three days after your symptoms start. Over 98% of people in the U.S. have some COVID immunity from vaccines or prior infections.
Some people may have symptoms that get worse about 5 to 7 days after symptoms start. Most people with COVID-19 have mild to moderate symptoms. But COVID-19 can cause serious medical complications and lead to death. Older adults and people who already have medical conditions are at greater risk of serious illness.
June 26, 2025 – The new COVID-19 variant that now makes up about a third of U.S. COVID cases has a signature symptom: a painful sore throat that feels like "razor blades." "This 'razor blade sore throat' was reported as a common symptom in China," where the variant first emerged in May, said Matthew S.
Taking Care of Yourself at Home
The most common COVID Nimbus symptoms include:
Nasal congestion or a runny nose. Fever and muscle aches. Sneezing. Digestive symptoms like nausea or diarrhea (less common, but possible)
The symptoms of the Delta Plus variant are slightly different from the original strain of the virus. However, loss of smell and taste, fever, cold and cough are some of the common symptoms of the COVID-19 variant. In case of a severe infection caused by the Delta Plus variant, symptoms may include: Shortness of breath.
People with COVID-19 have a wide range of symptoms ranging from mild symptoms to severe illness. Symptoms may appear 2-14 days after exposure to the virus. Symptoms may start as mild, and some people will progress to more severe symptoms.
Severity: Delta caused more severe disease than other variants in people who weren't vaccinated. Early studies from Scotland and Canada, both cited by the CDC, suggested Delta was more likely to result in hospitalization in the unvaccinated.
A: The Delta variant has an incubation period slightly shorter than the incubation period for Alpha and Beta but longer than the one for Omicron. On average, you'll start experiencing symptoms of the Delta variant 4.3 days after exposure to the virus. Q: Can you test positive for COVID-19 during the incubation period?
Common symptoms of the COVID-19 Delta Variant can sometimes be mistaken for allergies:
To relieve COVID-19 symptoms fast, focus on rest, fluids, and OTC meds for fever/pain (ibuprofen, acetaminophen) and cough, while staying home to prevent spread; high-risk individuals should contact a doctor about antivirals like Paxlovid, which must start within 5 days of symptoms, as treatment significantly helps manage the illness and prevent worsening.
With the ChAdOx1 nCoV-19 vaccine, the effectiveness of two doses was 74.5% (95% CI, 68.4 to 79.4) among persons with the alpha variant and 67.0% (95% CI, 61.3 to 71.8) among those with the delta variant.
Currently, the dominant variant nationwide is XFG, with 61% of cases, followed by XFG.14.1, with 15% of cases, and XFG.1, with 5% of cases. "The original omicron variant is gone now," says Dr. Rupp. "Currently subvariants of omicron are circulating, including XFV, NW.1 and XFZ."
The R0 tells us how many other people, on average, one infected person will pass the virus on to. Delta has an R0 of 5-8, meaning one infected person passes it onto five to eight others, on average. This compares with an R0 of 1.5-3 for the original strain.
The beta variant was the most deadly of all the COVID-19 strains that the World Health Organization deemed variants of concern, according to a meta-analysis published Jan.
The higher transmissibility of the Delta variant leads to a larger pool of people getting infected. Unfortunately, this also includes increased numbers among children and unvaccinated elderly persons.