A recent study reports that a 25-year-old male from Nevada (USA) with no known immunodeficiency 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 reinfection. Both infections were symptomatic, and the second infection was more severe than the first, with hospitalization and oxygen administration for hypoxia.
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The Lancet magazine published a report documenting a case of re-infection with SARS-CoV-2. The case concerned a 25-year-old man living in Reno, Nevada, USA.
The patient fell ill on 25 March 2020 with symptoms attributable to COVID-19: sore throat, headache, cough, nausea, and diarrhea. On 18 April 2020, the patient asked to be examined and was swabbed with a positive result for SARS-CoV-2 infection. The patient reported complete recovery of symptoms on 27 April 2020 and repeated the swab test on 9 May and 27 May 2020, with negative results in both cases. On 31 May 2020, the patient had a fever, headache, dizziness, cough, nausea, and diarrhea, so he treated himself at home. Five days later, on 5 June 2020, the patient, with hypoxia, asked to be examined and was admitted to the hospital. The patient was diagnosed with atypical pneumonia and was given oxygen. Analyses performed on the day of admission confirmed the presence of SARS-CoV-2 by RT-PCR and evidence of IgM and IgG antibodies. The patient did not have any condition or treatment that could suppress the immune response.
The genetic discordance of the two samples of SARS-CoV-2 was greater than could be explained by a short-term in vivo evolution. These results suggest that the patient was infected with SARS-CoV-2 on two separate occasions by a genetically distinct virus. Therefore, previous exposure to SARS-CoV-2 may not guarantee total immunity in all cases.
Current knowledge about other coronaviruses suggests that humans develop some immunity after infection, but that reinfection is possible. This was the first reinfection reported in the United States, but there are other reports being verified in other parts of the world. The article tells us that reinfections from SARS-CoV-2 may occur and that the second infection may be more severe than the first. However, these individual reports do not tell us what the risk of reinfection is, nor the risk of serious illness in the event of a second infection. We know little about how the virus changes during the course of a single infection and a better understanding of this phenomenon will help us distinguish between continuation and reinfection.
According to the authors, everyone, with or without a previous diagnosis of COVID-19, should take the same precautions to avoid SARS-CoV-2 infection. The implications of reinfections could be relevant to the development and application of the vaccine.
Richard L Tillett, Joel R Sevinsky, Paul D Hartley, Heather Kerwin, Natalie Crawford, Andrew Gorzalski, Chris Laverdure, Subhash C Verma, Cyprian C Rossetto, David Jackson, Megan J Farrell, Stephanie Van Hooser, Mark Pandori. Genomic evidence for reinfection with SARS-CoV-2: a case study. The Lancet Infectious Diseases, 2020, ISSN 1473-3099. https://doi.org/10.1016/S1473-3099(20)30764-7.