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

Abstract

Background: There is growing concern about individuals reported to suffer repeat COVID-19 disease episodes, these in a small number of cases characterised as de novo infections with distinct sequences, indicative of insufficient protective immunity even in the short term. Methods: Observational case series and case-control studies reporting 33 cases of recurrent, symptomatic, qRT-PCR positive COVID-19. Recurrent disease was defined as symptomatic recurrence after symptom-free clinical recovery, with release from isolation > 14 days from the beginning of symptoms confirmed by qRT-PCR. The case control study-design compared this group of patients with a control group of 62 patients randomly selected from the same COVID-19 database. Results: Of 33 recurrent COVID-19 patients, 26 were female and 30 were HCW. Mean time to recurrence was 50.5 days which was associated with being a HCW (OR 36.4 (p < 0.0 0 01)), and blood type A (OR 4.8 (p = 0.002)). SARS-CoV-2 antibodies were signifcantly lower in recurrent patients after initial COVID-19 (2.4 ± 0.610; p < 0.0 0 01) and after recurrence (6.4 ± 11.34; p = 0.007). Virus genome sequencing identified reinfection by a different isolate in one patient. Conclusions: 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 renfection, 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.

Risk of SARS-CoV-2 reinfection after natural infection

“…From that study, the investigators estimated risk of reinfection to be approximately 7%. 8 In The Lancet, Christian Hansen and colleagues report their population study of a Danish cohort investigating the risk of becoming positive for SARS-CoV-2 by PCR for the second time, presumed to indicate reinfection. 9 The study makes use of data from Denmark's national PCR-testing strategy whereby approximately 4 million people took 10•6 million PCR tests.…”

Reduced mortality rate after coronavac vaccine among healthcare workers

“…Healthcare workers have a high risk of exposure to the coronavirus disease-2019 (COVID-19) ( 1 ) and we lost many colleagues during this pandemic worldwide. As healthcare workers are high risk, they are one of the main groups for vaccine trials and population studies which its importance increased during pandemic due to priorisation of healthcare workers for COVID-19 vaccine.…”

Infection, recovery and re-infection of farmed mink with SARS-CoV-2

“…This should be compared with the situation in rhesus macaques where primary infection did protect against reinfection at about 1 month post-initial infection (13, 20) and in humans where protection from reinfection may last at least eight months (12, 21) . However, some cases of re-infection have been reported in health care workers in Brazil (22) , although this seems to have occurred in people who only developed a weak immune response during the initial infection. Furthermore, only about 50% of people in DK, who were over 65 years of age and had been infected with SARS-CoV-2, were found to be protected against re-infection (23) .…”