Recurrence of COVID-19 infection symptoms in short time; reinfection or reactivation? Three cases of three healthcare workers and a literature review.

Background: Since the beginning of the COVID-19 pandemic, many research papers have been published focusing on some recurrence cases of symptoms after a long period of free symptoms with a negative RT-PCR retest. There is no crucial evidence until now of the possibility of recurrence, immune system reactivation, or reinfection. Methods: Three cases of resident doctors who recovered from COVID-19 but represented symptoms with new positive RT-PCR were discussed. Clinical data, laboratory tests, RT-PCR results, and antibodies titers all were collected. Moreover, many cases from the literature have been reviewed and compared. Results: The long-term exposure has not succeeded in forming an effective immune response, especially, since they do not have any significant history of chronic illnesses or a diagnosed immune disorder. While the antibody response occurred only in the second patient, it did not prevent new infection, but did it control the severity of the infection or its complications? Conclusion: Our three patients are health workers and have been in direct contact with COVID-19 patients. The inflammatory response parameters may not be reliable in predicting the activation of the immune response and the formation of the antibodies. We still need to find answers for reactivation and reinfection issues.

Correlation of Pattern Reversal and Flash Visual Evoked Potential Latencies With Optical Coherence Tomography Measures in Patients With Optic Neuropathy and Patients With Multiple Sclerosis Without Optic Neuropathy.

PURPOSE: The object of the study is to relate the pattern reversal visual evoked potential (PRVEP) and flash VEP (f-VEP) latencies with retinal neurons and their fibers. METHODS: We studied 104 eyes. Forty-two eyes from patients with optic neuritis (ON), 28 eyes from patients with multiple sclerosis without involvement of the optic nerves (MS-non-ON), and 34 eyes of normal controls. RESULTS: Pattern reversal visual evoked potential latency is more delayed in patients with ON than in patients with multiple sclerosis nonON. Flash visual evoked potential (f-VEP) latency was delayed in both categories. Peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell/inner plexiform layer (GCIPL) thickness was lower in patients with ON and multiple sclerosis non-ON. In patients with ON, f-VEP latencies correlated negatively with pRNFL thickness but not GCIPL thickness. In patients with ON, PRVEP latencies did not correlate with pRNFL thickness but correlate negatively with GCIPL thickness. CONCLUSIONS: Patients with ON have delayed VEPs and thinner optical coherence tomography values. Flash visual evoked potentials correlate with pRNFL, indicating axonal pathology. PRVEP correlate with GCIPL, indicating ganglion cell pathology. Abnormal PRVEP with preserved normal f-VEP indicate isolated myelin damage. Abnormalities in both PRVEP and f-VEP indicate myelin and axonal damage in the optic nerve. Combining the results of PRVEP, f-VEP, pRNFL, and GCIPL, one can define the location, type, and extent of the lesion in the macula and optic nerve.