key: cord-349690-hgdjbeht
authors: Alonso, Fábio de O. Martinez; Sabino, Bruno Duarte; Guimarães, Maria Angelica Arpon Marandino; Varella, Rafael Brandão
title: Recurrence of SARS‐CoV‐2 infection with a more severe case after mild COVID‐19, reversion of RT‐qPCR for positive and late antibody response: case report
date: 2020-08-14
journal: J Med Virol
DOI: 10.1002/jmv.26432
sha: 
doc_id: 349690
cord_uid: hgdjbeht

In general, SARS‐CoV‐2 replication in the host reaches its peak in the first week of infection, decreasing rapidly afterwards, while some level of immunity is build up. Yet, the infection seems to follow a distinctive course in some individuals, reactivating after the apparent resolution of symptoms(1‐3). We report here the first case to be disclosed of a more vigorous COVID‐19 recurrence with SARS‐CoV‐2 RNA redetection and late antibody response, and also the first to address COVID‐19 recurrence in Brazil. This article is protected by copyright. All rights reserved.

Different reports indicate that reactivation or re-infection by SARS-CoV-2 are possible, although the event appears to be unusual 4 . Although cases vary in terms of serological data, timing of reactivation and clinics, patients who retested positive to SARS-CoV-2 generally have a mild or asymptomatic course 5, 6 , which is perhaps the result of some level of immunity, while symptomatic reactivation is rare but may happen 7 . Our patient, on the other hand, presented a more potent form of COVID-19 after more than 40 days from the first mild infection, and with a detectable antibody response only after the second infectious episode. Our hypothesis is that the first mild infection was not sufficient to build up a detectable humoral response 8 , which This article is protected by copyright. All rights reserved.

occurred only after 14 days of a second more severe episode. In addition, the absence of detectable antibodies in the first episode may have allowed for a new infection, rather than a recurrence. However, as we did not investigate viral genetics at different times, such a statement is hypothetical.

A limitation of this study is the absence of cell culture assays, which could indicate the presence of infectious particles. Also, a false-positive result in the first RT-qPCR test cannot be excluded, so that the patient only became infected with SARS-CoV-2 afterwards 4 . However, given the 1) high specificity of RT-qPCR test;

2) presentation of symptoms coinciding with the positive RT-qPCR; and 3) viral detection in close family members living in the same residence during COVID-19 symptoms (data not shown); such false result is unlikely. Regarding the ELISA teste used (S: 100%, E: 92.5%) 9 , although its accuracy is compatible do LFA tests, the latter presents more inconsistencies, being useful as a screening tool in the absence of ELISA and RT-PCR 10 .

In this paper, we describe a COVID-19 recurrence from a mild to a moderate form after convalescence, with RT-qPCR turning positive and antibody detection after more severe symptoms. These findings, although summarized in a case report, raise questions about the influence of the severity of the infection on the immune response and the host's susceptibility, which can have important epidemiological consequences, and should be better understood.

Recurrence of positive SARS-CoV-2 in patients recovered from COVID-19

Recurrence of positive SARS-CoV-2 RNA in COVID-19: A case report

Clinical characteristics of severe acute respiratory syndrome coronavirus 2 reactivation

Retest positive for SARS-CoV-2 RNA of "recovered" patients with COVID-19: Persistence, sampling issues, or re-infection?

Positive RT-PCR Test Results in Patients Recovered From COVID-19

The clinical characteristic of eight patients of COVID-19 with positive RT-PCR test after discharge

Recurrence of COVID-19 after recovery: a case report from Italy

A case of transient existence of SARS-CoV-2 RNA in the respiratory tract with the absence of anti-SARS-CoV-2 antibody response

Clinical performance of different SARS-CoV-2 IgG antibody tests

Comparison of diagnostic accuracies of rapid serological tests and ELISA to molecular diagnostics in patients with suspected coronavirus disease 2019 presenting to the hospital

This paper was supported by Laboratório Contraprova Análises, Ensino e Pesquisas LTDA. Varella RB. was partially supported by National Council for Scientific and Technological Development -CNPq.

The authors declare no conflicts of interest

The study was approved by the University Hospital Ethical Committee of the Fluminense Federal University (register 30926020.2.0000.5243). This article is protected by copyright. All rights reserved.