"It is not the same disease as we were seeing with delta and the previous variants," said Dr. John Swartzberg, U.C Berkeley Infectious Diseases and Vaccinology clinical professor emeritus.
U.C Berkeley infectious diseases expert Dr. Swartzberg said this study confirms what clinicians are seeing. Eye-opening characteristics of how the virus is infecting the human body with omicron versus delta.
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"People who are infected with omicron tend to get more upper respiratory disease. Nose, throat, more congestion in the upper air ways. People who had delta in previous infections had more systemic symptoms like fever, body aches," said Dr. Swartzberg.
The study by UCSF researchers, the Chan Zuckerberg Biohub and the Latino Task Force found that the most common symptom during omicron were cough, followed by sore throat, congestion and very rarely loss of smell or taste.
"If you were boosted ironically you got more upper airway congestion like nose is stuffier. If you were boosted, you just had a couple of the mRNA jabs or if you weren't vaccinated at all you didn't get necessarily as much upper airway congestion, but you got more sick in terms of fever and bad body aches," said Dr. Swartzberg.
The Latino Task Force was key in gathering this data. They followed up with those who tested positive at their Mission test site and tracked their symptoms.
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"One thing also that we found through the omicron is that at the end of the five days recommended isolation, most people still tested positive. So, the importance to continue to test is very high," said Susan Rojas with the Latino Task Force.
Their data also found that fevers were "less common among persons who had received boosters compared to unvaccinated people or those who received the primary series."
"What we can infer is that those who are boosted were presenting a lot more of the congestion symptoms. Which means that the immune system was recognizing the virus a lot quicker and making it harder to advance," said Rojas.
This study is pending peer-review.