First Potential Reinfection Case with SARS-Cov-2 in Lebanon: A Case Study

Methods: A 28-year-old woman who is a nurse presented to our health care service in our hospital on 2 occasions. The first was on the 1st of November 2020, when she had mild symptoms of SARSCoV-2 infection, and the second was on the 24th of December, following an incidence of close contact with a confirmed COVID-19 case at the hospital unit where she is working. Nasopharyngeal swabs were obtained from the patient at each presentation and during follow-up. Rtq PCR testing was done to confirm SARS-CoV-2 infection. IgM and IgG were quantified in serum to monitor the immune response of this case.


Introduction
One of the key questions amidst the Covid-19 pandemic is understanding how long immunity may last for people exposed to SARS-CoV-2. As the protective immunity against this virus is not fully understood, more information is needed to fill the gaps in our understanding. Protection against severe disease has been shown in animal models and inferred in humans infected with DOI: 10.26717/BJSTR.2021.33.005456 the virus. Deng et al. showed that the primary exposure to SARS-CoV-2 protects against reinfection in rhesus macaques [1]. Cases of re-infection are rarely reported which could mean that Immunity is probable, at least in the short term. Several published and confirmed cases of reinfection were reported [2][3][4][5][6][7][8]. They showed an interval between episodes from 48 to 185 days. The first case of re-infection of COVID-19 was reported in Hong Kong with second episode of asymptomatic infection. Two studies in USA showed a Genomic evidence of a case report for symptomatic reinfection with SARS-CoV-2 within a period of 48 [2]. and 90 days [4]. Recently, Hanrath et al. observed no symptomatic reinfections in a cohort of healthcare workers [8]. As more cases of reinfection surface may help the scientific community to understand better how frequently natural infections with SARS-CoV-2 induce the level of immunity and the correlates of protection. This information is key to understanding which vaccines are capable of crossing that threshold to confer individual and herd immunity.

Study Case and Clinical Specimens
We present a case report of 28-year-old female was a nurse at our hospital with no history of clinically significant underlying conditions. She had no sign of compromised immunity. The patient provided written signed informed consent. Samples were collected in Beirut cardiac institute. Nasopharyngeal swab samples from the patient were collected into a sterile container containing VTM.

Results
On November first, she had the following symptoms: a fever, a cough, muscle pain and sudden loss of smell and taste. After a nasopharyngeal swab, she was tested positive for SARS-CoV-2 via a PCR-test with high viral load. The patient was isolated for three weeks, after which she tested negative twice before returning to

Discussion
Recently, several cases of reinfection have been documented worldwide. Our case report presents details of the first individual in Lebanon to have asymptomatic potential reinfection with SARS-CoV-2: a female 28-year-old whose first and second positive tests were carried out 54 days apart, with two consecutive negative tests in between. The patient was symptomatic with high viral load in the first episode and asymptomatic in the second one. This has similarities with the reinfection case in Hong Kong that described reinfection in a 33-year-old patient within a period of 142 days [2].
In the USA, a reinfection was described in a 25-year-old male within a period of 48 days. The patient was symptomatic during both episodes, with the second episode being more severe [3]. Another similar case of reinfection was described in the USA in a 42-year-old male, 90 days after the first infection episode [4]. Van Elslande et al.
reported reinfection in a 52-year-old female from Belgium, within a period of 93 days with mild symptoms during both episodes [5].

Prado-Vivar et al. reported reinfection in a 46-year-old male from
Ecuador with symptoms during both episodes while the first and the second test were carried out 63 days apart. This patient had a contact with a confirmed COVID 19 patient before the second infection [6]. Moreover, two young healthcare workers were tested during screening campaigns and were reported as reinfected cases. Our patient had no immunological disorder that would involve the facilitation of reinfection, nor was she taking any immunosuppressive medication. Furthermore, A Chinese study found that among the COVID-19 cases released, 14% were retested as positive for SARS-CoV-2 over a period ranging from 2 to 19 days.
They showed that there was no link established between re-positive test and weaker immunity in these cases. In addition, a study on 285 re-positive cases, showed that 59.6% of re-positive cases were detected by screening and 44.7% were due to symptoms with an average of 44.9 days. 89.5% of these cases had Ct values> 30 and all had negative viral cell cultures [11]. In our case, the patient had a high-risk close contact with a confirmed COVID-19 case one week before the second positive result. Six out of eight of her colleagues were infected following this contact. The two positive tests were separated by two negative PCR tests. Furthermore, two independent PCR positive results were obtained in the potential second reinfection with a moderate viral load (CT-value =27, 3 viral genes). The IgG test showed a moderate increase of the level of IgG.
It should be noted that the frequency of reinfection is very rare and cannot be defined by the cases mentioned so far. But if our patient and the other cases mentioned are in fact re-infections, the initial exposure to SARS-CoV-2 may not result in full immunity levels. A major limitation of our case study is that we were unable to do the sequencing and perform an evaluation of the immune response to the first episode of SARS-CoV-2 infection. We were also unable to fully assess the effectiveness of the immune responses during the 2 episodes.

Conclusion
Previous exposure to SARS-CoV-2 does not necessarily translate into guaranteed full immunity. Our results may have implications for the role of vaccination. In addition, since influenza regularly shows the challenges of effective vaccine design [12], it is important to mobilize people to take precautions to prevent infection with SARS-CoV-2, regardless of whether or not they have already been diagnosed. Further work is essential to study and evaluate immune reactions in vivo vitro after reinfection.