Most people with Omicron probably don’t even know they’re infected, according to a recent small study, which says that 56% of people who are infected with this variant of coronavirus are unaware of their infection.
This has an upside and a downside, depending on how you look at it, reports Time magazine.
“It’s good news in some ways, since it underscores the fact that Omicron tends to cause relatively mild symptoms (or no symptoms at all) in vaccinated people. The downside is that many people are possibly spreading the virus unintentionally.”
Medscape reports that the study, which appeared in JAMA Open Network, looked at 210 hospital patients and employees in the Los Angeles area. More than half who tested positive didn’t know it – because they had no symptoms, or they assumed they merely had a cold or allergies.
“The findings support early data from around the world suggesting that throughout the pandemic, anywhere from 25% to 40% of SARS-CoV-2 infections have been asymptomatic, which presents challenges for public-health officials trying to control the spread of the virus,” Time reports.
The study found that awareness of infection rose after at-home tests became available this year. About three-quarters of people in January and February didn’t know their status, for example.
“Findings of this study suggest that low rates of Omicron variant infection awareness may be a key contributor to rapid transmission of the virus within communities,” the authors wrote. “Given that unawareness of active infection precludes self-initiated interventions, such as testing and self-isolation, even modest levels of undiagnosed infection can contribute to substantial population-level transmission.”
Study details
Awareness of SARS-CoV-2 Omicron Variant Infection Among Adults With Recent COVID-19 Seropositivity
Sandy Joung, Joseph Ebinger, Nancy Sun, et al
Key Points
Question What proportion of individuals who recently contracted the SARS-CoV-2 Omicron variant were aware of their infectious status?
Findings In this cohort study of 210 adults with evidence of seroconversion during a regional Omicron variant surge, 56% reported being unaware of any recent Omicron variant infection.
Meaning Findings of this study suggest that low rates of Omicron variant infection awareness may be a key contributor to rapid transmission of the virus within communities.
Abstract
Importance
Some individuals who were infected by the SARS-CoV-2 Omicron variant may have been completely unaware of their infectious status while the virus was actively transmissible.
Objective
To examine awareness of infectious status among individuals during the recent Omicron variant surge in a diverse and populous urban region of Los Angeles County.
Design, Setting, and Participants
This cohort study analysed the records of adult employees and patients of an academic medical centre who were enrolled in a longitudinal COVID-19 serological study in Los Angeles County, California. These participants had 2 or more serial anti-nucleocapsid IgG (IgG-N) antibody measurements at least 1 month apart, with the first occurring after the end of a regional Delta variant surge (September 15, 2021) and a subsequent one occurring after the start of a regional Omicron variant surge (December 15, 2021). Adults with evidence of new SARS-CoV-2 infection occurring during the Omicron variant surge period through May 4, 2022, were included in the present study sample.
Exposures
Recent Omicron variant infection as evidenced by SARS-CoV-2 seroconversion.
Main Outcomes and Measures
Awareness of recent SARS-CoV-2 infection was ascertained from review of self-reported health updates, medical records, and COVID-19 testing data.
Results
Of the 210 participants (median [range] age, 51 (23-84) years; 136 women [65%]) with serological evidence of recent Omicron variant infection, 44% (92) demonstrated awareness of any recent Omicron variant infection and 56% (118) reported being unaware of their infectious status. Among those who were unaware, 10% (12 of 118) reported having had any symptoms, which they attributed to a common cold or other non–SARS-CoV-2 infection. In multivariable analyses that accounted for demographic and clinical characteristics, participants who were health care employees of the medical center were more likely than nonemployees to be aware of their recent Omicron variant infection (adjusted odds ratio, 2.46; 95% CI, 1.30-4.65).
Conclusions and Relevance
Results of this study suggest that more than half of adults with recent Omicron variant infection were unaware of their infectious status and that awareness was higher among health care employees than nonemployees, yet still low overall. Unawareness may be a highly prevalent factor associated with rapid person-to-person transmission within communities.
Medscape article – Most People With Omicron Don’t Know They’re Infected (Open access)
See more from MedicalBrief archives:
Omicron has higher asymptomatic carriage rate – Ubuntu study
SA cohort study shows reduced chance of death or severe illness with Omicron
Why Omicron doesnʼt need its own custom COVID vaccine
Estimated 85% of Gautengers had COVID-19 at least once before Omicron wave