Cases of re-infection with SARS-CoV-2 are being documented. While some of the second infections have been mild, some have been serious. At least one has been fatal.
Some news media provide a tracker of reported cases of re-infection including BNO news (Netherlands)
Update 17 October: Pakistan has recorded its first case of re-infection. Media sources are reporting that the man died due to complications. He first tested positive for the virus in May and then later in October. Other cases of re-infections have also been noted in the country but no fatalities reported as yet.
Update 16 October: The first case of re-infection has been reported in Sweden in a 53-year-old woman who tested positive for COVID-19, first in May and again in August. Sahlgrenska University Hospital has confirmed that she was infected twice after having analysed the genome of the two virus strains.
Update 15 October: A case of re-infection has been confirmed in Israel. According to a study, the individual was a 20-year-old woman who was first diagnosed in April and later in August. She was mildly symptomatic during the first episode but was apparently asymptomatic during the second one.
Spain has also reported its first case of re-infection in a 62-year-old man who was first diagnosed in March and later in August. His symptoms were mild for the first infection but was serious for the second infection.
Update 13 October: An 89-year-old woman in the Netherlands has died following re-infection with COVID-19. According to the case report, she recovered from the first COVID-19 infection. Two months later, after starting a course of chemotherapy for an underlying health condition, she developed fever, cough and shortness of breath. COVID-19 was again diagnosed, she deteriorated and died. The genetic material of the virus differed from the first infection, and she is considered to have had a second infection.
Further Update 13 October: The Lancet published a case study regarding one of the re-infection cases in the United States. The publication discusses a 25-year-old man from the state of Nevada who was first infected in April, and then again in early June. The man had two negative tests in-between his two positive results. All four tests were done using the RT-PCR method. The authors state that the second, re-infection, was from a different strain. They state that this evidence supports the idea that previous exposure may not guarantee immunity.
Update 6 October: Two healthcare workers in a hospital in northern India have been documented to have asymptomatic re-infection. They originally tested positive to SARS-CoV-2 in May, and were asymptomatic. One tested positive for the second time in August, and the other in September. They were again asymptomatic. Genetic analysis showed the virus was different to the strain in May, confirming re-infection, rather than ongoing infection. They were found to have higher viral loads in the second infection. The genetic change in the SARS-CoV-2 virus of the second infection may have resulted in any antibodies developed after the first infection being ineffective at preventing then second infection.
Update 29 September: A study which looked at re-infection in "intense re-exposure setting" in Qatar found evidence of re-infection in 54 people out of over 130,000 cases. They conclude "SARS-CoV-2 reinfection can occur but is a rare phenomenon suggestive of a strong protective immunity against reinfection that lasts for at least a few months post primary infection." The paper is not-yet peer reviewed.
Update 26 September: A study from India documents confirmed SARS-CoV-2 infections in four healthcare workers (HCWs). The four had been infected in May and June, and developed a second infection in July. "[...] in all four HCWs the first episode was asymptomatic or mildly symptomatic and the second episode was marginally more clinically severe than the first. "The paper is not-yet peer reviewed.
In the United States, at least three cases of re-infection have been documented. A paper from Washington State, which is not yet peer-reviewed, provides details of a patient in their 60's with underlying health problems. They were hospitalised in March with severe COVID-19, and were discharged after twice testing negative 6 weeks later. He developed cough and weakness over 3 months later with a second COVID-19 infection. The second infection was less severe than the first.
A 42-year-old man in Virginia, with no underlying health conditions, was first infected in March. He recovered from cough, fever and sore muscles 10 days later. He remained well until 51 days later, when he developed a more severe COVID-19 infection. The paper documenting this case concludes "this second infection was more severe, potentially due to immune enhancement, acquisition of a more pathogenic strain, or perhaps a greater inoculum of infection as the second exposure was from within the household."
The University of Nevada announced it was studying a case of SARS-CoV-2 reinfection. The patient was first infected in April, tested negative twice after that before testing positive again in June. The genetic analysis showed that the virus in June was not the same as the virus in April, indicating a new second infection.
Update 31 August: A 46-year-old man in Ecuador had the virus in May and then again in August, according to reports from the Microbiology Institute of the San Francisco University of Quito. They said genetic testing showed each infection was caused by a different strain of the virus. In May, he had mild symptoms and tested positive, Members of his family also had COVID-19. He tested negative later on for the virus, but was tested in August after having symptoms. This test was positive. More than 80 days had elapsed since his first illness to his second.
Posted 25 August: Two cases of re-infection with SARS-CoV2 have been reported in the Netherlands and Belgium. Media sources are reporting that a case in the Netherlands is an elderly man with low immunity. In Belgium, a woman has been infected again after three months since she was first diagnosed with the disease in March. Earlier, Hong Kong reported a case in a man who have gotten the virus again.