Topline
Some 56% of a sample of people who tested positive for Covid-19 during the winter omicron surge were not aware they had the coronavirus, a new study found, adding to concerns that low levels of virus detection helps fuel the spread of the highly contagious variant.
A person holds a positive Covid test.
Key Facts
Among those who were unaware they had Covid, most were asymptomatic, while only 10% experienced symptoms, which they believed to be a common cold or another type of infection, according to the study, published in the Journal of the American Medical Association Wednesday, which relied on data from 210 participants with recent Covid infections during the height of a spike in omicron infections.
Health care workers had more awareness of Covid infections than other types of employees, researchers found.
The findings should motivate people who have been exposed or are feeling under the weather to “get a quick test,” said Susan Cheng, a study author with the Department of Cardiology at the Smidt Heart Institute at Cedars-Sinai Medical Center, adding “the better we understand our own risks, the better we will be” at protecting public health.
Key Background
The omicron variant was first discovered in South Africa in November 2021, though experts believe the strain might have circulated in other countries even earlier than that. The extremely contagious variant caused a surge in cases last winter during which daily Covid hospitalizations at their peak topped 20,000. The variant has specific mutations in its spike proteins—the part of the virus that binds to the human cell—that helps it evade the immune system as well as antibodies from previous coronavirus infections and vaccines. Previous studies have estimated anywhere from 25% to 80% of people may not experience symptoms during an omicron infection, which is linked to less severe symptoms than previous variants, according to researchers. At the same time, some studies have also found asymptomatic people or people with mild symptoms can trigger outbreaks and rapid spread of Covid. The federal government has made efforts to increase the availability of at-home rapid tests by offering billions of free tests to be mailed directly to households. The Food and Drug Administration also recommended in June pharmaceutical companies retool coronavirus booster shots to target the omicron variant, and in particular, its substrains BA.4 and BA.5. Those boosters are expected in late fall.
Surprising Fact
Omicron subvariant BA.5 accounted for 88.8% of all coronavirus infections in the U.S. the week ending August 13, according to Centers for Disease Control and Prevention estimates. The subvariant quickly rose to dominance after making its way to the U.S. in late March and fueled a surge in cases. New coronavirus infections and hospitalizations have begun to fall slightly after starting to peak again in mid-July. The United States averaged 95,209 new infections per day the week ending August 15, still up from the 30,558 daily cases reported as of April 10, but below the 127,740 average new daily cases reported in the week ending July 20.
Further Reading
Highly Contagious BA.5 Variant Becomes Dominant In U.S. As Covid Cases Rise (Forbes)
Source: https://www.forbes.com/sites/madelinehalpert/2022/08/17/many-infected-with-omicron-covid-infections-dont-know-study-suggests/