Updated Jan. 24, 2022
The delta variant, which originated in India, began spreading rapidly and making news around the middle of June 2021. Here's what health experts have learned about the delta variant:
The symptoms of the delta variant appear to be the same as the original version of COVID-19. However, physicians are seeing people getting sicker quicker, especially for younger people. Recent research found that the delta variant grows more rapidly – and to much greater levels – in the respiratory tract.
Typically, vaccinated people are either asymptomatic or have very mild symptoms if they contract the delta variant. Their symptoms are more like those of a common cold, such as cough, fever or headache, with the addition of significant loss of smell.
UC Davis Health physicians have noted that a number of younger patients, when they come in with critical illness, say that they wish they would have gotten the COVID-19 vaccine. Many patients have told their physicians, "Why did I not get the vaccine?" or "Why did I not listen?"
Health experts across the country are wearing masks themselves even though they're fully vaccinated to protect against the delta variant and other COVID-19 mutations. They're also advising vaccinated people to avoid large gatherings and mask up indoors where the vaccination status of other people is unknown.
In the late summer and fall or 2021, the delta variant was the dominate strain of COVID-19 in the U.S. Since December 2021, the omicron variant has taken over as the main mutation of COVID-19. Although the omicron variant is likely more contagious than any other strain to date, it's generally causing less severe symptoms than the delta variant.