#15,440Although we've seen a number of reports of presumed `relapses' in `recovered' COVID-19 patients - six days ago, in HKU Med Announces 1st Documented Reinfection With SARS-CoV-2 - we saw the first real evidence of reinfection by the novel coronavirus by scientists in Hong Kong.
Less than twenty-four hours later, two more reports emerged from Europe (see Two More Reports of SARS-CoV-2 Reinfection (Netherlands & Belgium).
What removes these cases from the `likely relapsed' column to `likely reinfected' has been the ability to compare the genetic code of their first coronavirus infection to their second one. In each of these cases, virus samples were taken and genetically sequenced, and they showed genetically distinct variants of SARS-CoV-2.
Yesterday, researchers at the University of Nevada, Reno School of Medicine (UNR Med), led by its Nevada State Public Health Laboratory (NSPHL), announced that they too had laboratory evidence of a likely reinfection in a presumably recovered COVID-19 patient (Male, 25).
Unlike the three previously mentioned cases - whose reinfections were described as either mild or asymptomatic - this patient's second bout was significantly worse than the first, and was serious enough to require hospitalization.
The 16-page report (as yet, not peer reviewed) is available on SSRN pre-print server. I've only reproduced the abstract, so follow the link to download and read the full PDF file. I'll have a postscript when you return.
TILLETT, RICHARD and SEVINSKY, JOEL and HARTLEY, PAUL and KERWIN, HEATHER and CRAWFORD, NATALIE and GORZALSKI, ANDREW and LAVERDURE, CHRISTOPHER and VERMA, SUBHASH and ROSSETTO, CYPRIAN and FARRELL, MEGAN and JACKSON, DAVID and Pandori, Mark and VAN HOOSER, STEPHANIE16 Pages Posted: 27 Aug 2020AbstractThe degree of protective immunity conferred by infection with SARS-CoV-2 is currently unknown. As such, the possibility of reinfection with this virus is not well understood. Herein, we describe the data from an investigation of two instances of SARS-CoV-2 infection in the same individual. Through nucleic acid sequence analysis, the viruses associated with each instance of infection were found to possess a degree of genetic discordance that cannot be explained reasonably through short-term in vivo evolution. We conclude that it is possible for humans to become infected multiple times by SARS-CoV-2, but the generalizability of this finding is not known.Funding Statement: Nevada IDEA Network of Biomedical Research (INBRE) supported this work and the publication was made possible by grants from the National Institute of General Medical Sciences (GM103440 and GM104944) from the National Institutes of Health.Declaration of Interests: Missing.Ethics Approval Statement: Missing.Keywords: SARS-COV-2, CORONAVIRUS, SEQUENCE, REINFECTIONSuggested Citation:
TILLETT, RICHARD and SEVINSKY, JOEL and HARTLEY, PAUL and KERWIN, HEATHER and CRAWFORD, NATALIE and GORZALSKI, ANDREW and LAVERDURE, CHRISTOPHER and VERMA, SUBHASH and ROSSETTO, CYPRIAN and FARRELL, MEGAN and JACKSON, DAVID and Pandori, Mark and VAN HOOSER, STEPHANIE, Genomic Evidence for a Case of Reinfection with SARS-CoV-2. THELANCETID-D-20-05376, Available at SSRN: https://ssrn.com/abstract=3681489
The idea that acquired immunity following SARS-COV-2 infection (or vaccination) might be short-lived isn't new, and has been the topic of numerous blogs over the past few months (see COVID-19: From Here To Immunity).
We'd seen evidence - as far back as 2016 (see EID Journal: Antibody Response & Disease Severity In HCW MERS Survivors) - that MERS-COV antibodies declined quickly HCWs with mild or moderate illness.
Similarly, in July (see Kings College: Longitudinal Evaluation & Decline of Antibody Responses in SARS-CoV-2 infection), researchers reported that `the magnitude of the nAb response is dependent upon the disease severity'. They also found a significant percentage of mild cases saw their nAb titers drop to near baseline within 60 days post-infection.
It should be noted that nAb titers aren't the only measure of potential post-infection immunity, as the role of T-Cells in fighting this virus is poorly understood
While it is becoming obvious that re-infection can occur with SARS-COV-2 - how often that happens remains unknown. Samples or sequencing data from first infections are rarely available for comparison, making discovery of these four cases somewhat serendipitous.
For now, these cases are more cautionary signs than warning klaxons.
That said, if over the next few months we start to see a significant number of (suspected or confirmed) reinfections with accompanying illness, it would not be a positive development.