To: Posterior reversible encephalopathy syndrome in a child with severe multisystem inflammatory syndrome due to COVID-19 Translated title: Para: Síndrome da encefalopatia posterior reversível em uma criança com síndrome inflamatória multissistêmica grave devido à COVID-19

Posterior reversible encephalopathy syndrome (PRES) may present with diverse clinical symptoms including visual disturbance, headache, seizures and impaired consciousness. MRI shows oedema, usually involving the posterior subcortical regions. Triggering factors include hypertension, pre-eclampsia/eclampsia, renal failure, cytotoxic agents and autoimmune conditions. The mechanism underlying PRES is not certain, but endothelial dysfunction is implicated. Treatment is supportive and involves correcting the underlying cause and managing associated complications, such as seizures. Although most patients recover, PRES is not always reversible and may be associated with considerable morbidity and even mortality.

Posterior reversible encephalopathy syndrome is a rare clinical and radiological syndrome characterized by vasogenic edema of the white matter of the occipital and parietal lobes, which are usually symmetrical, resulting from a secondary manifestation of acute dysfunction of the posterior cerebrovascular system. We describe a case of posterior reversible encephalopathy syndrome secondary to SARS-CoV-2 infection in a 9-year-old boy who developed acute hypoxemic respiratory failure and required assisted mechanical ventilation. The child developed multisystem inflammatory syndrome, and he was monitored in the pediatric intensive care unit and was provided mechanical ventilation and vasoactive agents for hemodynamic support. Additionally, he developed pulmonary and extrapulmonary clinical manifestations along with neuropsychiatric manifestations that required close follow-up and were verified using brain magnetic resonance imaging for timely intervention. Currently, there are few reports of children with posterior reversible encephalopathy syndrome associated with multisystem inflammatory syndrome.

The COVID-19 pandemic caused by SARS-CoV-2 started in China in December, 2019 and has spread across several continents. As at 5th December, 2020, there have been 65,257,767 confirmed cases of COVID-19 worldwide with 1,513,179 deaths (2.31% mortality) Humoral immune responses are highly specific and they provide long-lasting protection against reinfection and the titre of antibodies that persist is directly related to the extent of protection afforded. As research towards generating effective vaccines against SARS-CoV-2 are in advanced stages, there is need for continued robust review of the available data from various studies on the antibody response from natural SARS-COV-2 infection as regards the potential for immunity against re-infection following exposure to the antigens of this virus. Antibodies against RBD of the spike protein of SARS-CoV-2 were detected in majority of patients, appearing within the first week, peaking by 3rd week. IgG antibodies was observed to last beyond 120days and it is predicted seroreversion would happen at about 42.72 months. Antibody response to SARS-CoV-2 correlates with the severity of COVID-19. It was also higher amongst males, hospitalized patients, older people and patients with higher BMI and was lower among smokers, immunosuppressed individuals and patients using anti-inflammatory medications. Persistence of high levels of antiSARS-CoV-2 neutralizing antibodies (IgG) following natural infection is thus likely to be associated with conferment of long term protection against re-infection or attenuate disease severity if reinfection occurs. There is a good potential for development of immunity against SARS-CoV-2 infection in vaccinated individuals.