The nasopharynx smear was negative – but doctors from the University Hospital Basel found Sars-CoV-2 in a patient’s skin sample. The case shows how little is known about the new virus.
Scientists from the University Hospital Basel have detected Sars-CoV-2 viruses in a skin sample from a patient. The nasopharynx smear, known as the so-called PCR test, and the patient’s antibody test, however, were negative. The researchers published the case on Friday in the renowned medical journal The Lancet.
PCR tests can still be negative despite infection
“Even if it’s just one case, it shows us that the PCR tests are not as good as we think,” says study author Elisabeth Roider. “Just because such a test is negative, we cannot automatically conclude that the person affected is not infected with the novel coronavirus.” The fact that the test for antibodies, which can indicate a cleared disease, also turned out negative, confirms the assumption that not every infected person forms antibodies. “I believe that this means we are far from herd immunization,” says Roider. This observation also raises the question of how helpful a vaccine can really be: “Do you have to be re-vaccinated every three or four months to achieve protection?”
The Basel scientists removed a four millimeter large piece of inflamed skin from the left side of the torso from an 81-year-old who had a fever and a pronounced rash and examined it for the coronavirus. The medical professionals rule out contamination of the sample. “We also found virus cells on the vessels under the electron microscope, so we are sure that they come from the patient herself,” says Roider. A possible infection through the skin was also discussed.
Because the virus concentration was very low, the researchers assume that the infection took place via the respiratory tract and that the virus made its way from there. The skin changes caused by Sars-CoV-2 can include frostbite-like lesions, drug eruptions and rashes that resemble vasculitis or hives.
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