Recurrent COVID-19 reinfection and re-emergence of a chronic infection reservoir?, a Brazilian study

Recurrent COVID-19 including evidence of reinfection and enhanced severity in thirty Brazilian healthcare workers


  • We describe 33 patients with recurrent COVID19 and a positive PCR.
  • Recurrence is associated with working as a healthcare professional, blood-group A, and low IgG response to infection.
  • Evidence from differential virus sequencing between the first and second episode supports de novo reinfection.
  • Recurrent episodes tended to be more severe, with one fatal infection.


This is the first detailed case series showing COVID-19 recurrence with qRT-PCR positivity. For one individual, detection of phylogenetically distinct genomic sequences in the first and second episodes confirmed bona fide reinfection, but in most cases the data do not formally distinguish between reinfection and re-emergence of a chronic infection reservoir. These episodes were significantly associated with reduced Ab response during initial disease and argue the need for ongoing vigilance without an assumption of protection after a first episode.

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