COVID-19 relapse with prolonged viral shedding up to 60 days or re-infection, in 3 frontline healthcare workers with recurrent symptoms and persistent SARS-CoV-2 PCR positivity in Ireland, a developing diagnostic challenge: A case report

Jonathan McGrath (  jonathan.mcgrath@umail.ucc.ie ) Mater Misericordiae University Hospital https://orcid.org/0000-0001-8227-0976 Tara McGinty Mater Misericordiae University Hospital Maureen Lynch Mater Misericordiae University Hospital Edel O'Regan Mater Misericordiae University Hospital Dominic Natin Mater Misericordiae University Hospital Peter O'Gorman Mater Misericordiae University Hospital John S Lambert Mater Misericordiae University Hospital https://orcid.org/0000-0001-5404-2415

symptoms. All completed 14 day periods of self-isolation with full resolution of symptoms. Each patient has a clinical role and was involved in the management of COVID-19 patients following return to work. Patient 1 was admitted to hospital 44 days after initial illness, with cough, dyspnoea and a concurrent diagnosis of neurosyphilis. SARS-CoV-2 PCR was positive with Ct value 31.36 and remained positive for at least 60 days following initial illness onset. A full clinical recovery followed. Patients 2 and 3 represented to the Emergency Department with recurrent respiratory symptoms 29 and 40 days following initial illness onset respectively. SARS-CoV-2 PCR was demonstrated in each with Ct values 31.16 and 30.72 respectively. Each subsequently made a full recovery following a second period of self-isolation.

Conclusions:
These cases demonstrate the diagnostic di culties in determining intermittent presentation of COVID-19 infection with prolonged viral shedding, or re-infection with new virus following return to work. As the pandemic progresses, this represents a growing diagnostic challenge impacting patient assessment, staff deployment following illness and infection control.

Background
Up to May 23 rd 2020, the Corona Virus Disease 19 (COVID-19) pandemic has resulted in more than 24,400 con rmed cases in Ireland, with 7,813 (32%) involving Healthcare Workers (HCW)(1). Despite a growing evidence base, a number of key clinical considerations remain uncertain that are of particular relevance to frontline staff, regarding both clinical care and broader infection control concerns.
The possibility of re-infection with COVID-19 following initial illness remains in question as does the clinical signi cance of prolonged viral shedding. Development of antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is well documented (2), but whether this form of response confers protective immunity, or over what timeframe has yet to be rmly established. As more staff become involved in the care of COVID-19 patients, the answers to these pertinent questions are of growing importance and urgency.
We present 3 cases of COVID19-infected healthcare workers with patient-facing roles, each with distinct episodes of recurrent symptoms, following initial resolution and with persistently positive SARS-CoV-2 PCR results, ranging up to 60 days post onset of illness.

Case Presentations
Case 1 In mid-March 2020, a 29 year old HCW presented to a community testing centre reporting a 7 day history of fever, dry cough, dyspnoea, sore throat and arthralgia. SARS-CoV-2 RNA was detected on oro/nasopharyngeal swab via reverse transcription polymerase chain reaction (rtPCR) with a cycle threshold (Ct) value of 21.72. The severity of symptoms and presence of normal vital signs meant that hospital admission was not indicated and the patient was placed in self-isolation for 14 days.
Past medical history included epilepsy, for which he took Sodium Valproate 500mg BD and asthma, for which he took Budesonide/Formoterol 160mcg/4.5mcg BD and Salbutamol 100mcg PRN.
During isolation, the patient made a good clinical recovery with complete resolution of symptoms at least ve days prior to completion.
On returning to work, 21 days after initial symptom onset, he was stationed on a dedicated COVID-19 ward providing care for infected patients. There were no patients under his care receiving non-invasive ventilation.
Two days later he experienced blurring of vision in his left eye, pain on eye movements and pre-orbital headache. Eight days following this, he noticed a recurrence, though mild, of dry cough and exertional dyspnoea. Ophthalmological assessment revealed bilateral uveitis. A repeat swab taken due to recurrent respiratory symptoms, detected SARS-CoV-2 with a Ct value of 31.36, 30 days after the initial result and 36 days after initial onset of symptoms. Prednisolone acetate 1% eye drops were prescribed as a topical agent for the uveitis and on the advice Infectious Diseases services, he entered a second 14-day selfisolation period, pending serology results.
Eight days into isolation, he was admitted to hospital with an erythematous, macular rash affecting his chest/back, tinnitus, bilateral pre-orbital headache and vertigo. Ongoing dry cough and exertional dyspnoea was also reported. He was not in respiratory distress with RR 28/min, O 2 97% on room air (RA), BP 117/65 mmHg, HR 87 bpm and a temperature of 36.1 o C. Lung auscultation did not reveal any crepitations or wheeze. Cranial nerve exam revealed mild pain on lateral eye movements. Routine bloodwork was unremarkable and Chest X-Ray was clear.
Serology demonstrated a positive Rapid Plasma Reagin (RPR) 1:128, Syphilis IgM EIA and T. pallidum particle agglutination at 1:20480. HIV 1+2 antigen/antibody was negative. Serology results coupled with rash indicated secondary syphilis. Due to ocular involvement, a diagnosis of neurosyphilis was made, with a background of possible persistent or recurrent COVID-19 infection. Lumbar puncture revealed a clear CSF with 0 WCC/RCC, protein 348mg/L, glucose 3.2 mmol/L (serum glucose 6.2 mmol/L). CSF VDRL and SARS-CoV-2 PCR were negative. The patient commenced treatment with intravenous Penicillin G.
Over the course of his 14-day inpatient stay, the patient remained positive for SARS-CoV-2 on repeated oro/nasopharyngeal swabs despite full resolution of respiratory symptoms, including one performed 53 days following his initial positive result and 60 days following his initial symptoms in March (Figure 1.) The patient was diagnosed with a mild-moderate asthma exacerbation and possible recurrent/unresolved COVID-19 infection. Standard asthma exacerbation treatment was prescribed, with nebulised bronchodilators and oral prednisolone. There was no indication for systemic antibiotics or directed COVID-19 therapy. A good clinical improvement was achieved and the patient was discharged 48 hours later to complete a second period of self-isolation with remote monitoring, via a smartphone application, measuring oxygen saturation/temperature twice daily as per local protocols. Dyspnoea resolved after a further 7 days (Figure 1). Anti-SARS-CoV-2, antibodies were detected using a point of care lateral ow test kit 51 days after initial symptom onset.

Case 3
In mid-March, a 25 year old HCW with no signi cant past medical history presented to the Emergency Department with fever, sore throat, dry cough, fatigue and myalgia on a background of recent travel to Italy. rtPCR testing for SARS-CoV-2 was positive, with a Ct value 26.58. Vital signs were all within normal range, laboratory investigations and Chest X-Ray were unremarkable. Following a 24-hour period of observation, the patient was discharged for a planned 14 days of self-isolation. The patient had an uneventful clinical course, reported full resolution of symptoms, except for ongoing fatigue, and returned to work 19 days after initial symptom onset.
In mid-April, 36 days following the initial positive swab result and 40 days following the initial onset of symptoms, the patient re-presented to the Emergency Department reporting a 5 day history of mild dry cough, myalgia and 10 days of sore throat/coryzal symptoms. Vital signs showed O 2 99% on RA, RR

Discussion And Conclusions
We describe here 3 cases of COVID-19 in frontline HCWs with distinct episodes of recurrent symptoms following a subjective resolution of their initial syndrome. It is not clear whether this represents a relapse of symptoms (intermittent presentation) of COVID-19 infection with prolonged viral shedding, or reinfection with new virus following return to work.
The reported symptom-free period between episodes was a minimum 15, 18, and 18 days, for Patient 1,2 and 3 respectively. All 3 patients worked in separate hospitals, with clinical, patient-facing roles and reported appropriate PPE use, without known breaches, for contact with known COVID-19 patients. Patient 3 was de ned as a close contact of a known case in the intervening period between her two illnesses.
Duration of SARS-CoV-2 PCR positivity varies, with one review reporting a median of 12 days (range 5 to 52 days) across a number of studies (3). Prolonged PCR positivity is demonstrated in our 3 cases, with detectable SARS-CoV-2 RNA at 53, 29 and 36 days post initial results for patient 1,2 and 3 respectively. The longest detectable period, in patient 1, was 60 days after the onset of his original symptoms. To the best of our knowledge, this represents one of the longest durations of SARS-CoV-2 PCR positivity reported (4).
All 3 patients were young (range 29 to 36 years) and had mild disease at initial presentation de ned by symptom severity, normal vital signs and radiology (5). Patients 2 and 3 had a history of asthma and took regular inhaled corticosteroids, but no other signi cant co-morbidities were noted. While severe disease, ICU admission (6) and old age (7) have all been associated with prolonged viral shedding, a cohort study of 23 patients by Kai-Wang et al. (8) demonstrated viral RNA detection in saliva after 20 or more days in 23% of mild cases. One study (7) of 262 COVID-19 patients observed that those who tested positive following discharge tended to be younger, with milder forms of COVID-19 during their initial hospitalisation; however in this cohort, patients remained asymptomatic, while the three patients reported above had 2 distinct symptomatic presentations.
We analysed Ct values for each of our cases, where data was available, to explore the concept of prolonged viral shedding. Ct values for each successive result demonstrate a progressive increase for all patients. It is possible that this represents a reducing viral load from the original infection, but increasing Ct values alone do not however, out rule re-infection with the secondary episodes. Additionally, these results are not routinely available to clinicians at point of diagnosis and therefore cannot be used to aid clinical decisions at initial patient assessment.
A limitation in the interpretation of our ndings is the lack of a negative SARS-CoV-2 PCR post initial symptom resolution in our 3 patients. However, a single negative PCR result needs careful interpretation; Xiao et al. (9), in a study of 70 patients, observed that 21.4% experienced a "turn positive" of nucleic acid detection by rtPCR for SARS-CoV-2 after two consecutive negative results. The author suggests this may be related to a false negative of the rtPCR test and prolonged nucleic acid conversion. While there is increasing published data documenting prolonged SARS-CoV-2 PCR detection, our cases demonstrate this phenomenon concurrently with recurrent symptoms, making clinical interpretation of its consequence more challenging.
Presence of anti-SARS-CoV-2 IgG was demonstrated in these patients via point of care, lateral ow SARS-CoV-2 IgM/IgG Antibody Detection Kits. Due to the timing of patient presentation during the pandemic, quantitative measurement was not available during the acute episodes and as such, IgG presence was con rmed 59, 51 and 61 days after initial symptom onset in Patient 1, 2 and 3 respectively. Kai-Wang et al. (8) demonstrated that despite development of antibodies against SARS-CoV-2, viral RNA could still be detected in oropharyngeal saliva samples from a third of patients for 20 days or longer. Therefore, had antibody testing been available earlier in the clinical course for these patients, it is unlikely that it would have been able to fully clarify the relapse/re-infection issue, as antibodies may be positive even during productive COVID-19 infection. Similarly, Long et. Al (2) demonstrated that the proportion of patients with positive virus-speci c IgG reached 100% approximately 17-19 days after symptom onset, however, this did not necessarily equate to clinical recovery. Our 3 cases had mild severity illness and as such were able to return to work soon after their isolation was completed. It may be possible that potential reexposure to the virus occurred before adequate immune responses had developed and conferred protection. Wu et al. (10) found that while detectable, 30% of 175 studied patients failed to develop high levels of neutralising antibodies following recovery from COVID-19 infection, and levels were lower in those with less severe disease. Thus detection of antibodies, while promising, may not yet be a rm indicator of protection against re-infection with SARS-CoV-2.
A number of other limitations are noted in this patient analysis. First, the number of cases described is small and larger cohort studies are required to further clarify the issues raised. Furthermore, while anti-SARS-CoV-2 IgG was demonstrated in all patients, direct temporal links to symptoms cannot be established due to lack of availability of antibody testing at time of presentation.
As the COVID-19 pandemic progresses, frontline workers will have increasing and repeated exposure to SARS-CoV-2 in occupational settings. These cases demonstrate that uncertainty remains regarding possibility of re-infection and clinical infectivity in prolonged shedding. This, coupled with the ongoing concern regarding neutralising antibody protection, means clinical assessment of this cohort may remain a challenge, impacting on diagnostics, isolation duration and re-deployment following illness.