Fever Most Common Non-Respiratory Symptom of SARS-CoV-2 Infection

While COVID-19 is usually considered a respiratory ailment, non-respiratory symptoms have been quite common throughout the pandemic. A new study looked at the effect of SARS-CoV-2 variants on non-respiratory features and mortality of COVID-19 in both fully vaccinated (FV) and not fully vaccinated (NFV) people and found that fever was the most common non-respiratory symptom. Find out the others.

SAN DIEGO – Respiratory symptoms tend to create suspicion of COVID-19 and lead to testing, but what is the most common non-respiratory feature of infection with SARS-CoV-2?

A recent presentation at the ATS (American Thoracic Society) 2023 International Conference suggests an answer to that question – fever. That held to be true despite COVID variant or vaccination status, according to the researchers, who add that who were not fully vaccinated had a higher risk of dying when infected with either the Omicron or Delta variant.


The University of California San Diego-led study used the University of California Health Covid Research Data Set’s (UC CORDS) medical records of 63,454 patients who had been treated in a University of California medical center for COVID-19. The scientists applied statistical tests to determine the relationship between non-respiratory features, vaccination status and differences in mortality between infection with the Omicron and Delta variants.

“We determined that we would conduct this study because the scientific literature has shown that, although COVID is a respiratory disease, it affects multiple organ systems,” said corresponding author Shannon Cotton, BSN, RN, and ICU nurse at UC Irvine. “We wanted to determine which organ systems and features were most affected by the different SARS-CoV-2 variants, which were more likely to lead to death, and the effect of being vaccinated or not fully vaccinated.”

“We found that the risk of developing non-respiratory features of COVID-19 was statistically higher in those who were not fully vaccinated, across all variants,” added Cotton, who is a UC San Diego Health and nursing science PhD student and Behrens Fellow at the Sue and Bill Gross School of Nursing.

The retrospective study sought to determine the effect of SARS-CoV-2 variants on non-respiratory features and mortality of COVID-19 in both fully vaccinated (FV) and not fully vaccinated (NFV) people who sought care at a University of California medical center. 

To achieve that, the study team conducted a retrospective review of the medical records of 63,454 unique patients. The focus was on non-respiratory features, vaccination status, and mortality between variants.

“Fever was the most common feature across all variants regardless of vaccine status,” the authors report. They also point out the following:

  • Fever was significantly higher in NFV during the Delta and Omicron waves (p=.001; p=.001);
  • Cardiac features were statistically higher in NFV during Omicron;
  • Tachycardia was only a feature of NFV during Delta and Omicron;
  • Diabetes and GI reflux were features of all variants regardless of vaccine status.

The study advises that the odds of death were significantly increased among those not fully vaccinated in the Delta and Omicron variants (Delta OR: 1.64, p = 0.052; Omicron OR: 1.96, p < 0.01). Vaccination was associated with a decrease in the frequency of non-respiratory features.

“Risk of non-respiratory features of Covid-19 is statistically higher in those who are not fully vaccinated across all variants, and some features of Covid-19 were only present in NFV people,” the researchers conclude. “Risk of death and correlation with vaccination status varied among variants.”

“Our findings speak to the importance of vaccination as the odds of dying were significantly increased in those not fully vaccinated,” Cotton emphasized.

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