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Genomic evidence for a case of reinfection with SARS-CoV-2

Our take —

This preprint study, which had not been peer reviewed, reports that a 25-year old living in Reno, Nevada, without known immunodeficiencies, was infected with SARS-CoV-2 once in March, recovered in April, and was reinfected in May 2020. Genomic sequencing provides strong evidence that this was a reinfection. Both infections were symptomatic, and the second infection led to severe disease, requiring oxygen support and hospitalization; we have no data on the patient’s immune response following the first infection. This was the first reinfection reported from the USA, but reinfections have now been reported from Hong Kong and Europe. This adds to our understanding that reinfections with SARS-CoV-2 will occur, and that the second infection could be more severe than the first. However, these individual reports do not tell us what the risk for reinfection is, nor the risk of severe disease during the second infection. We understand little about how the virus changes over the course of a single infection and a better understanding of this phenomenon will help us distinguish between continuing and reinfection.

Study design

Case Series

Study population and setting

This is a case report of a 25-year old man residing in Reno, Nevada, USA.

Summary of Main Findings

The patient became ill on March 25, 2020 with symptoms compatible with COVID-19: sore throat, headache, cough, nausea and diarrhea. On April 18, 2020, the patient presented for care and had a nasopharyngeal swab collected which showed evidence of SARS-CoV-2 RNA. The patient reported complete resolution of symptoms on April 27 and was tested again on May 9 and May 27 by RT-PCR, and both tests were negative. On May 31, the patient reported to care with self-report of fever, headache, dizziness, cough, nausea and diarrhea. Five days later, on June 5, the patient presented again to care with hypoxia and was hospitalized; chest x-ray diagnosed atypical pneumonia, and the patient required oxygen support. A respiratory specimen collected on the day of hospitalization confirmed SARS-CoV-2 by RT-PCR, and a blood sample had evidence of IgM and IgG antibodies. The patient had no conditions or treatment that would suppress immune response. Sequence analyses of the viruses in the first and second infections suggests that they are not closely related, though both are consistent with other viruses circulating in Reno. The second infection was concurrent with a confirmed SARS-CoV-2 infection in a household member.

Study Strengths

The authors conducted two independent sequence analysis studies to increase their confidence that the patient had been infected twice. They also conducted an analysis of samples from both infections to confirm that the person who provided them was the same, to rule out mistakes in sample labeling as a reason for the result.


There are no data presented on the immune response the patient had following the first infection, so it is impossible to determine if they developed neutralizing antibodies. This study is comprised of only one patient so the implications for this finding on risk of reinfection more broadly are unknown.

Value added

Evidence from other coronaviruses suggests that humans develop some immunity following infection but that reinfection is possible; a number of examples of reinfection with SARS-CoV-2 have now been confirmed using genetic sequencing, from Hong Kong and Europe. This is the first reported reinfection in the USA. This patient’s experience shows that the immune response from one infection with SARS-CoV-2 may not always produce sufficient protection against a second severe episode in a young person without known immune deficiencies.

This review was posted on: 2 September 2020