Is the Omicron Variant More Transmissible Than The Delta Form
Updated On May 26, 2022
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Even though it's understood now that omicron generally causes less severe disease for the individual than the delta variant, omicron's extreme contagiousness compared with previous variants that dominated the globe has caused huge numbers of people to get sick, with some inevitably getting seriously ill. And comparing omicron with delta should also come with the understanding that the delta variant was more contagious than earlier variants, and also appeared more likely to put people in the hospital. That is, when comparing the omicron and delta variants, we're comparing omicron with a very serious illness.
Does Omicron Cause Less Severe Disease Than Delta?
For the individual, yes. (The record numbers of infections continue to cause many deaths and overwhelm hospital systems.) A preprint study published last month looked at data from about 52,000 people infected with the omicron variant, and about 17,000 infected with delta, in southern California. Compared with patients who had the delta variant, omicron patients had a 53% reduced risk of hospitalization, a 74% reduced risk of ICU admission and a 91% reduced risk of death. The study has not yet been peer-reviewed.
When talking about the study at a briefing last month, a researcher said that none of the people infected with omicrons in the study required mechanical ventilation. This backs up another study from researchers in Hong Kong who found that while extremely contagious, omicron isn't as good at replicating in the lungs as delta, likely leading to less severe disease.
The new research also adds to what researchers from many other countries, including South Africa, have found: Though more contagious than any other variant, omicron doesn't seem to be making people quite as sick as the delta variant did. And when it does make people sick enough to require hospitalization, those hospital stays tend to be shorter.
Is It Omicron Or A Cold?
Given the extremely high number of COVID-19 cases and communities spread throughout the world, you should probably treat your sniffles or sore throat like they're COVID-19, and stay home if you're sick. But of course, the only way to know for sure is to get tested. In fully vaccinated and boosted people, especially, omicron is causing mild cases of COVID-19 that can mimic run-of-the-mill cold symptoms.
In a Dec. 10 report by the CDC, the symptoms of 43 omicron cases (some of the first reported in the US) were described. When it came to common symptoms, most people (89%) reported a cough, 65% were fatigued and 59% of them were congested or had a runny nose. Only 8% of the 43 people reported losing their sense of smell or taste, which has affected many people with previous COVID-19 infections, caused by other variants. Fourteen percent of people in the report had COVID-19 previously. Cough and loss of smell are also less common symptoms of COVID-19 caused by the delta variant compared with earlier variants.
Fortunately, the omicron variant is easily detected through PCR tests, according to Fauci, which can then be confirmed through labs that use genomic sequencing.