At the end of March, I wrote about a preliminary study conducted by Stanford emergency physician Ian Brown, MD, that indicated that a significant number of people diagnosed with COVID-19 are also simultaneously co-infected with other respiratory viruses, including influenza or rhinovirus.
This is important to know because, as I explained:
The findings challenge the assumption that people are unlikely to have COVID-19 if they have another type of viral respiratory disease.
"Currently, if a patient tests positive for a different respiratory virus, we believe that they don't have COVID-19," said Nigam Shah, MBBS, PhD, associate professor of medicine and of biomedical data science at the medical school. "However, given the co-infection rates we've observed in this sample, that is an incorrect assumption."
Now Stanford emergency department physician James Quinn, MD, and resident David Kim, MD, PhD, together with clinical virologist Benjamin Pinsky, MD, PhD, have extended this analysis to include more than 1,200 samples, collected from people from multiple sites in Northern California who were experiencing a cough, fever or other symptoms of a respiratory infection. They published their results yesterday in JAMA.
The take-home message is the same: infection with a common respiratory virus or bacteria doesn't mean the person can't also be infected with SARS-CoV-2, the virus that causes COVID-19. In fact, 7.5% of people who tested positive for the presence of one or more common respiratory pathogens were also infected with SARS-CoV-2. Conversely, 20.7% of people infected with SARS-CoV-2 were also co-infected with one or more common respiratory pathogens.
The authors conclude:
These results suggest higher rates of co-infection between SARS-CoV-2 and other respiratory pathogens than previously reported, with no significant difference in rates of SARS-CoV-2 infection in patients with and without other pathogens. The presence of a non-SARS-CoV-2 pathogen may not provide reassurance that a patient does not also have SARS-CoV-2.
Photo by Bret Kavanaugh