key: cord-0960746-qxt64bt1
authors: Fotouhi, Fatemeh; Salehi-Vaziri, Mostafa; Farahmand, Behrokh; Mostafavi, Ehsan; Pouriayevali, Mohammad Hassan; Jalali, Tahmineh; Mazaheri, Vahideh; Larijani, Mona Sadat; Tavakoli, Mahsa; AzitaEshratkhah mohammadnejad; Afzali, Neda; Zokaei, Afsaneh; Hosseini, SeyedeAtefe; Mortazavipour, Mohamad Mahdi; Oskouei, FaridehNiknam; Ramezani, Amitis
title: Prolonged Viral Shedding and Antibody Persistence in Patients with COVID-19
date: 2021-03-17
journal: Microbes Infect
DOI: 10.1016/j.micinf.2021.104810
sha: 3834275406d98240f716b0782dcee89b5b8df324
doc_id: 960746
cord_uid: qxt64bt1

SARS-CoV-2 as a new global threat has affected global population for one year. Despite the great effort to eradicate this infection, there are still some challenges including different viral presentation, temporal immunity in infected individuals and variable data of viral shedding. We studied 255 COVID-19 suspected individuals to assess the viral shedding duration and also the antibody development against SARS-CoV-2 among the cases. Real Time RT-PCR assay was applied to determine the virus presence and SARS-CoV-2 antibodies were evaluated using SARS-CoV-2 IgM and IgG kits. 113 patients were confirmed for COVID-19 infection. The patients were followed until negative PCR achieved. The median viral shedding among studied population was obtained 34.16 (±17.65) days which was not significantly associated with age, sex and underlying diseases. Shiver and body pain were found in prolonged form of the infection and also patients who had gastrointestinal problems experienced longer viral shedding. Moreover, IgG was present in 84% of patients after 150 days. According to this data, the median viral shedding prolongation was 34.16 days which indicates that 14 days isolation might not be enough for population. In addition, IgG profiling indicated that it is persistent in a majority of patients for nearly 6 months which has brought some hopes in vaccine efficacy and application.

According to the variable data which is emerging rapidly, inpatient and outpatient isolation span 74 has been controversial. Therefore, a clear vision of the viable viral shedding duration is critically 75 important to provide a unique guidance for transmission-based isolation precautions [1] . 76

The viral detection by PCR, is dependent on the time post illness initiation. In the first two weeks 77 of the infection phase, the virus could be detected mostly in sputum followed by nasal swabs, 78

while throat swabs were assessed unreliable eight days after symptom onset [2, 3] . A high viral 79

shedding rate has been found during the first week of symptoms with a peak on the fourth day 80 [4] . Viral shedding prolongation is among the current COVID-19 challenges which has been 81 uncharacterized after symptoms resolution [5] . 82

Some studies have demonstrated that prolonged viral shedding is correlated with severe 83 presentation of the virus. Zheng et al, in a retrospective cohort study on 96 patients observed 84

prolonged viral shedding in severe cases in comparison with mild cases [6, 7] . In a study on 85 MERS-CoV, diabetes was found to be correlated with prolonged detection of MERS-CoV RNA 86 [8] . A case report also showed that a COVID-19 infected case had viral shedding for 46 days 87 who was suffering from chronic hepatitis B infection and diabetes mellitus [9] . High fever at the 88 time of admission also resulted in longer SARS-CoV-2 shedding. In addition to social distancing 89 and quarantining of confirmed cases and contacts, viral shedding duration determination will 90

help reducing viral transmission. According to unclear features of the new virus, determination 91 J o u r n a l P r e -p r o o f of the viral shedding in different populations is essential to determine an effective standard 92 protocol in recovered patients' discharge [10] [11] [12] . 93

Furthermore, antibody measurement is a crucial key which provides essential data on infection 94

tracking. Population based serology could make a clear vision of the virus spreading pattern and 95

total attack rate along with the prevalence of serological conversion [13, 14] . case-fatality and attack rate and also to identify subjects who mounted a strong virus specific 105 antibody response which can be then detected and applied to treat patients via plasma therapy 106 [17, 18] . 107

Serological testing may also identify patients with past infection without PCR positivity and has 108 been used in surveillance to identify previous SARS-CoV-2 infection and provide the infectious 109 link between known cases. This kind of test may also provide better estimate of past SARS-CoV-110 2 infection among the community [5] . 111

Despite seroconversion, viral shedding has been shown to persist and virus has also been 112 cultured after SARS-CoV-2antibodies detection [19, 20] . Nearly up to half of SARS-CoV-2 113

patients have been reported to develop an antibody response on the 7 th day with the vast majority 114

seroconverting 15 days after symptom onset [19, 21] . 115

In this study, we aimed at characterization of SARS-CoV-2 viral shedding and antibody 116 assessment among Iranian COVID-19 infected subjects. 117

In individuals were also fully studied by the possible related risk factors to the viral shedding and 147 antibody development and persistence. 148

Data are presented as mean ± SD or, when indicated, as an absolute number and percentage. The 149

Chi-square, T-student, one-way ANOVA and Fisher tests were applied using SPSS 26 package 150

program for statistical analysis. P value less than 0.05 was considered significant. 151

Totally 255 suspected subjects (133 males, 122 females) were evaluated. 238 cases were 154 assessed by molecular tests from whom 113 patients were confirmed for the COVID-19 155

infection. The mean age was 40.65(±13.99) and the O and A blood types were the most frequent 156

respectively. 157

Anosmia, loss of taste, fever and body pain were significantly higher in the positive PCR 158 compared to the negative ones (P<0.05). The other outcome of the analytic data was that there is 159

an association between the age and the infection and older people were more susceptible to 160

acquire the disease (p<0.001). Moreover, infected population of males were twofold females. 161

There was no correlation between the underlying disease and COVID-19 acquiring in the 162 confirmed cases and non-infected subjects. (Tab.2). 163 164

The patients were followed until the disease resolution achieved by PCR test (Tab.3). The 166 earliest viral clearance was assessed 5 days whereas 91 days as the longest period after 167 symptoms onset. The median viral shedding was obtained 34.16 (±17.65) days which was not 168

significantly different between the men and women. Moreover, the studied population were 169 divided to two groups based on the age, >50 years and < 50 years. The mean duration of viral 170

shedding was 36.9 (±24.15) and 34.84 (±15.59) days in the groups, respectively with no 171 significant differences between them. 172

Among the investigated population, viral clearance was followed up weekly which showed 173 43.3% achieved it within 28 days whereas just 6.7% achieved negative PCR in14 days. 174

There was a significant association between some of the disease presentations and prolongation 175 of the virus shedding. Shiver and body pain were found in prolonged form of the infection and 176

also patients who had gastrointestinal problems (including abdominal pain, diarrhea, anorexia 177

and vomiting) experienced prolonged viral shedding, too. (Tab.4). 178

What is more, 9 patients (3.5%) used Chloroquine and also 44 subjects got Hydroxychloroquine. 179

Nevertheless, there was no association between the viral shedding and 180

Chloroquine/Hydroxychloroquine usage (Tab.4). 181

The serological data of IgM What is more, the IgM faint was observed in males two times sooner than females. The 190

individuals with O blood type were found to lose IgM sooner than the other groups (p=0.01). 191

There was no association between the gender and blood types with antibody detection. 192

Furthermore, 25 patients from those who were IgG positive agreed to participate in serial testing 193 antibody within at least 5 months which the obtained data showed that 84% were IgG positive 194 whereas 1 individual lost IgG after 5 months and the other case lost it after 6 months. Moreover, 195

IgG was not detected in one patient and in one case it was only present for 1 month. 196

In addition, there was no association between the disease severity and IgG raise time. Finally, the 197 subjects who did not suffer from earache reached the IgG development sooner than the rest. According to some classified data, SARS-CoV-2 viral shedding has been continued for 63 days 213

after symptom initiation and SARS-CoV-2 RNA was detectable in infected cases 1-3 days earlier 214 than symptom starts. Moreover, the disease severity had no effect on viral RNA detection even 215

in upper or lower respiratory tract although a correlation was observed between longer viral 216 In this study we also found that that IgG is present in 84% of patients after 180 days which is in 270 agreement with the mentioned studies, although the neutralizing potency is not achieved. 271

As the studies are growing worldwide and the tests' specificity is more achieved, SARS- J o u r n a l P r e -p r o o f J o u r n a l P r e -p r o o f

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