Dynamics of SARS-CoV-2 antibodies after natural infection: insights from a study on Pasteur Institute of Tunis employees.

This study aimed to assess the kinetics of antibodies against the SARS-CoV-2, following natural infection in a cohort of employees of the Institut Pasteur de Tunis (IPT) and to assess the risk of reinfection over a 12-months follow-up period. A prospective study was conducted among an open cohort of IPT employees with confirmed SARS-CoV-2 infection that were recruited between September 2020 and March 2021. Sera samples were taken at 1, 3, 6, 9 and 12 months after confirmation of COVID-19 infection and tested for SARS-CoV-2-specific immunoglobulin G (IgG) antibodies to the spike (S-RBD) protein (IgG anti-S-RBD) and for neutralizing antibodies. Participants who had an initial decline of IgG anti-S-RBD and neutralizing antibodies followed by a subsequent rise in antibody titers as well as those who tested positive for SARS-CoV-2 by RT-PCR after at least 60 days of follow up were considered as reinfected. In total, 137 individuals were included with a mean age of 44.7 ± 12.3 years and a sex-ratio (Male/Female) of 0.33. Nearly all participants (92.7%) were symptomatic, and 2.2% required hospitalization. Among the 70 participants with three or more prospective blood samples, 32.8% were reinfected among whom 11 (47.8%) reported COVID-19 like symptoms. Up to 12 months of follow up, 100% and 42.9% of participants had detectable IgG anti-S-RBD and neutralizing antibodies, respectively. This study showed that humoral immune response following COVID-19 infection may persist up to 12 months after infection despite the potential risk for reinfection that is mainly explained by the emergence of new variants.

Immunogenicity and Tolerance of BNT162b2 mRNA Vaccine in Allogeneic Hematopoietic Stem Cell Transplant Patients.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (ASCT) induces acquired immunodeficiency, potentially altering vaccine response. Herein, we aimed to explore the clinical tolerance and the humoral and cellular immune responses following anti-SARS-CoV-2 vaccination in ASCT recipients. METHODS: A prospective, non-randomized, controlled study that involved 43 ASCT subjects and 31 healthy controls. Humoral response was investigated using the Elecsys® test anti-SARS-CoV-2. Cellular response was assessed using the QFN® SARS-CoV-2 test. The lymphocyte cytokine profile was tested using the LEGENDplex™ HU Th Cytokine Panel Kit (12-plex). RESULTS: Adverse effects (AE) were observed in 69% of patients, encompassing pain at the injection site, fever, asthenia, or headaches. Controls presented more side effects like pain in the injection site and asthenia with no difference in the overall AE frequency. Both groups exhibited robust humoral and cellular responses. Only the vaccine transplant delay impacted the humoral response alongside a previous SARS-CoV-2 infection. Noteworthily, controls displayed a Th1 cytokine profile, while patients showed a mixed Th1/Th2 profile. CONCLUSIONS: Pfizer-BioNTech® anti-SARS-CoV-2 vaccination is well tolerated in ASCT patients, inducing robust humoral and cellular responses. Further exploration is warranted to understand the impact of a mixed cytokine profile in ASCT patients.

Immunogenicity of Mix-and-Match CoronaVac/BNT162b2 Regimen versus Homologous CoronaVac/CoronaVac Vaccination: A Single-Blinded, Randomized, Parallel Group Superiority Trial.

(1) Background: This study aimed to compare the immunogenicity of the mix-and-match CoronaVac/BNT162b2 vaccination to the homologous CoronaVac/CoronaVac regimen. (2) Methods: We conducted a simple-blinded randomized superiority trial to measure SARS-CoV-2 neutralization antibodies and anti-spike receptor binding domain (RBD) IgG concentrations in blood samples of participants who had received the first dose of CoronaVac vaccine followed by a dose of BNT162b2 or CoronaVac vaccine. The primary endpoint for immunogenicity was the serum-neutralizing antibody level with a percentage of inhibition at 90% at 21-35 days after the boost. A difference of 25% between groups was considered clinically relevant. (3) Results: Among the 240 eligible participants, the primary endpoint data were available for 100 participants randomly allocated to the mix-and-match group versus 99 participants randomly allocated to the homologous dose group. The mix-and-match regimen elicited significantly higher levels of neutralizing antibodies (median level of 96%, interquartile range (IQR) (95-97) versus median level of 94%, IQR (81-96) and anti-spike IgG antibodies (median level of 13,460, IQR (2557-29,930) versus median level of 1190, IQR (347-4964) compared to the homologous group. Accordingly, the percentage of subjects with a percentage of neutralizing antibodies > 90% was significantly higher in the mix-and-match group (90.0%) versus the homologous (60.6%). Interestingly, no severe events were reported within 30 days after the second dose of vaccination in both groups. (4) Conclusions: Our data showed the superiority of the mix-and-match CoronaVac/BNT162b2 vaccination compared to the CoronaVac/CoronaVac regimen in terms of immunogenicity, thus constituting a proof-of-concept study supporting the use of inactivated vaccines in a mix-and-match strategy while ensuring good immunogenicity and safety.

Incidence and risk factors of SARS-CoV-2 infection among workers in a public health laboratory in Tunisia.

The aim of this study was to measure the extent of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among workers at the Institut Pasteur de Tunis (IPT), a public health laboratory involved in the management of the COVID-19 pandemic in Tunisia, and to identify risk factors for infection in this occupational setting. A cross-sectional survey was conducted on IPT workers not vaccinated against coronavirus disease 2019 (COVID-19). Participants completed a questionnaire that included a history of reverse transcription-polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2 infection. Immunoglobulin G antibodies against the receptor-binding domain of the spike antigen (anti-S-RBD IgG) and the nucleocapsid protein (anti-N IgG) of the SARS-CoV-2 virus were detected by enzyme-linked immunoassay (ELISA). A multivariate analysis was used to identify factors significantly associated with SARS-CoV-2 infection. A total of 428 workers were enrolled in the study. The prevalence of anti-S-RBD and/or anti-N IgG antibodies was 32.9% [28.7-37.4]. The cumulative incidence of SARS-CoV-2 infection (positive serology and/or previous positive RT-PCR test) was 40.0% [35.5-44.9], while the proportion with asymptomatic infection was 32.9%. One-third of the participants with RT-PCR-confirmed infection tested seronegative more than 90 days postinfection. Participants aged over 40 and laborers were more susceptible to infection (adjusted OR [AOR] = 1.65 [1.08-2.51] and AOR = 2.67 [1.45-4.89], respectively), while tobacco smokers had a lower risk of infection (AOR = 0.54 [0.29-0.97]). The SARS-CoV-2 infection rate among IPT workers was not significantly different from that detected concurrently in the general population. Hence, the professional activities conducted in this public health laboratory did not generate additional risk to that incurred outside the institute in day-to-day activities.

First Report of Two Jaculus Rodents as Potential Reservoir Hosts of Leishmania Parasites in Tunisia.

This study shows, for the first time, natural Leishmania infection among Jaculus spp. in an endemic region of Tataouine, South Tunisia. To better characterize the transmission cycles in this complex focus of mixed transmission, Leishmania detection and species identification were performed by direct examination, internal transcribed spacer-1 (ITS1)-PCR-restriction fragment length polymorphism (RFLP), and sequencing of Jaculus (J.) jaculus (Linnaeus, 1758) and J. hirtipes (Lichtenstein, 1823) rodent species, which are frequently encountered in this area. Leishmania parasites were observed in 19 (41.3%) smears, while DNA parasites were detected in 28 (60.9%) Jaculus spp. spleens; among them, 12 (54.5%) were from 22 J. jaculus individuals and 16 (66.7%) were from 24 J. hirtipes individuals. Leishmania parasites were confirmed as Leishmania (L.) killicki (syn. L. tropica) in two J. hirtipes individuals (4.3%) and L. major (n = 24; 52.2%) in 10 J. jaculus and 14 J. hirtipes individuals. This finding represents the first evidence of natural infection with Leishmania parasites in rodents belonging to the Jaculus genus, providing the rationale to consider them as potential reservoir hosts of Old World Leishmania parasites in Tunisia and North Africa.

COVID-19 in Tunisia (North Africa): Seroprevalence of SARS-CoV-2 in the General Population of the Capital City Tunis.

Seroprevalence studies are essential to get an accurate estimate of the actual SARS-CoV-2 diffusion within populations. We report on the findings of the first serosurvey conducted in Tunis prior to the implementation of mass vaccination and analyzed factors associated with seropositivity. A household cross sectional survey was conducted (March-April 2021) in Tunis, spanning the end of the second wave and the beginning of the third wave of COVID-19. SARS-CoV-2 specific immunoglobulin G (IgG) antibodies to the spike (S-RBD) or the nucleocapsid (N) proteins were detected by in-house ELISA tests. The survey included 1676 individuals from 431 households. The mean age and sex ratio were 43.3 ± 20.9 years and 0.6, respectively. The weighted seroprevalence of anti-N and/or anti-S-RBD IgG antibodies was equal to 38.0% (34.6-41.5). In multivariate analysis, age under 10, no tobacco use, previous diagnosis of COVID-19, a history of COVID-19 related symptoms and contact with a COVID-19 case within the household, were independently associated with higher SARS-CoV-2 seroprevalence. More than one third of people living in Tunis obtained antibodies to SARS-CoV-2. Further studies are needed to monitor changes in these figures as Tunisian population is confronted to the subsequent epidemic waves and to guide the vaccine strategy.

Knowledge attitudes and practices toward seasonal influenza vaccine among pregnant women during the 2018/2019 influenza season in Tunisia.

BACKGROUND: The uptake and acceptance of the influenza vaccine (IV) among pregnant women remain unknown in Tunisia despite the increased influenza-related complications and death. The present study aimed to assess the IV uptake and acceptability and to describe related knowledge and attitudes among pregnant women in Tunisia. METHODS: A cross-sectional study was conducted in 84 Tunisian healthcare facilities over a period of three months (from March to May 2019). All pregnant women aged ≥18 years who sought antenatal care in related health structures were included in this study based on a multistage self-weighted sampling. We measured knowledge and attitudes towards the IV and assessed factors related to willingness for its uptake. RESULTS: The questionnaire was completed by 1157 pregnant women. More than half of the participants (60.2%; 95% confidence interval [CI] [57.3%-63.0%]) reported awareness about the IV. Among included PW, only 4.6%; 95% CI [3.5%-6.1%] received it during their current pregnancy. However, (36.8%; 95% CI [34.0%-39.6%]) declared their willingness to receive the vaccine in the next pregnancy. Recommendation by healthcare providers, identified to be the most trustful source of information, was the main reason for acceptance. However, the intention to accept the IV by pregnant women was significantly associated with such recommendation and perceived safety and effectiveness of this vaccine. CONCLUSION: Antenatal care visits are a precious opportunity that should not be missed by health care providers and especially gynecologists to promote the IV uptake by pregnant women in Tunisia.

Influenza vaccination knowledge, attitudes, and practices among Tunisian elderly with chronic diseases.

BACKGROUND: Generally, seasonal influenza does not cause severe infection in healthy adults, but for the elderly, an infection can pose a serious health concern. Although several measures can help prevent influenza, vaccination is considered the most effective. This study aimed to assess influenza vaccine uptake among elderly with chronic diseases in Tunisia during the 2018-2019 influenza season, and to identify knowledge, attitudes and barriers associated with influenza vaccine uptake. METHODS: During influenza season of 2018-2019, we conducted a national cross-sectional study among elderly with chronic disease who were attending primary and secondary health care facilities in Tunisia. We collected data regarding practices, general knowledge and attitudes related to influenza and influenza vaccine, using a standardized questionnaire. A multivariate analysis by logistic regression was performed to assess the factors influencing willingness to receive influenza vaccine. RESULTS: Among the 1191 surveyed elderly, 19.4% (95%CI 14.1-21.9) were vaccinated during the 2018-2019 influenza season and 64.7% (61.9-67.3) expressed willingness to be vaccinated in the next season regardless of vaccination status in the 2018-2019 season. Previous vaccination in the 2018-2019 influenza season was the most significantly associated factor with willingness to receive influenza vaccine (adjusted OR = 16.5 [3.7-72.4]). Significant associations were also observed between knowledge of influenza severity for the elderly as well as for those with chronic diseases and willingness to be vaccinated (p < 0.01). Likewise, participants who were convinced by flu vaccine effectiveness and those who were not concerned about vaccine side effects were more likely to be vaccinated (p < 0.001). The main reason that may lead to vaccine acceptance was a doctor's recommendation (41.1%), while the two main reasons that may lead to vaccine refusal were concerns about side effects (71.5%) and a belief that vaccine was ineffective in averting influenza illness (33.9%). Doctors were the most trusted source for information about influenza vaccine (91.5%). CONCLUSION: Our study revealed low influenza vaccination coverage among Tunisian elderly with chronic diseases believed to be at higher risk for severe acute respiratory infections and death if infected with influenza. Treating physicians' role in promoting influenza vaccination in this high-risk group seems to be crucial.

Knowledge, attitudes and uptake related to influenza vaccine among healthcare workers during the 2018-2019 influenza season in Tunisia.

BACKGROUND: The influenza vaccine (IV) is considered the most effective strategy to prevent seasonal influenza infection and annual vaccination of healthcare workers (HCWs) is recommended by the World Health Organization given their high mixing with patients. We assessed IV uptake among HCWs in the 2018-2019 season and explored their knowledge and attitudes regarding influenza immunization. METHODS: A cross-sectional study was conducted in 150 representative Tunisian health facilities from March to May 2019. We recruited 1231 HCWs with direct patient contact using self-weighted multistage sampling. Univariate and multivariate logistic regression analyses permitted to assess the factors associated with IV uptake in the 2018-2019 influenza season. RESULTS: Among 1231 health professionals enrolled in this study, less than half (36.6, 95% confidence interval [CI]: 33.9-39.4) received the IV at least once in their lives and only 15.3% (CI: 13.3-17.4) were vaccinated against influenza in the 2018-2019 influenza season. High confidence regarding IV efficacy, belief about the mandatory character of influenza vaccination for HCWs, and IV uptake in the 4 years preceding the 2018-2019 influenza season were independently associated with higher IV uptake by multivariate analysis. However, participants with high educational level were less likely to receive the IV than those with the lowest educational level. CONCLUSIONS: Our study revealed a low vaccination rate among Tunisian HCWs confirming the importance of tailored education programs targeting this population.

Mental health status of adults under institutional quarantine: a cross-sectional survey in Tunisia.

INTRODUCTION: restrictive measures imposed during the COVID-19 pandemic, such as quarantine, may induce psychiatric outcomes among concerned individuals. The present study aimed to describe the mental health status of Tunisian adults under mandatory institutional quarantine imposed during the COVID-19 pandemic, and to determine factors influencing the occurrence of psychiatric symptoms. METHODS: a cross-sectional phone survey was conducted from April to November 2020 using convenience sampling of persons who had experienced mandatory institutional quarantine. A standardized questionnaire was administered to participants including questions about socio-demographic characteristics and quarantine related information. Generalized anxiety disorder, depression symptoms, and sleep quality during quarantine were assessed using, respectively, the generalized anxiety disorder-7 (GAD-7), the centre for epidemiological studies depression (CES-D-10) and the insomnia severity index (ISI) scales. Bivariate and multivariate analyses were performed to determine factors associated with anxiety and/or depression and with clinical insomnia. RESULTS: among 506 participants, 38.3% experienced anxiety and/or depression symptoms (anxiety: 15.4%; depression: 37.4%) and 19.2% had clinical insomnia. The prevalence of anxiety and/or depression symptoms and insomnia were higher among women those who spent three hours or above on COVID-19 news, those who had economic difficulties due to COVID-19 pandemic, those who were not satisfied by the accommodation conditions of quarantine facilities, and those who had experienced stigma. CONCLUSION: high prevalence of psychiatric symptoms among quarantined individuals was found in this study. Psychological interventions should thus be an integral part of the COVID-19 control strategy in order to provide adequate psychological support to persons quarantined due to COVID-19.

Seroprevalence of hepatitis A virus infection in Central-West of Tunisia.

Hepatitis A infections still represent a major global health concern. During the past years, a transition pattern of the hepatitis A epidemiology was noted in many parts of the world. In Tunisia, there is not a recent survey on age-specific hepatitis A virus seroprevalence. This study aimed to investigate the seroprevalence of hepatitis A virus infection in Central-West Tunisia, representative of regions with lowest socioeconomic level in the country, before vaccine implementation. Sera obtained from the blood samples of subjects were screened for the detection of hepatitis A virus. The seroprevalence was evaluated by detection of total antibodies to hepatitis A virus using commercially available immunoassay kits. A total of 1379 subjects, aged 5-75 years (mean age: 29.0 ± 17.3 years) were studied. The global anti-hepatitis A virus seroplevalence was 84.7% (95% confidence interval: [82.6-86.5]). A higher hepatitis A virus seroprevalence was showed in subjects aged 10-14 years compared to those aged less than 10 years (50.0% vs. 31.0%). In subjects aged 20-29 years, a rapid increase in the hepatitis A virus prevalence was noted; it reached 97.0%. The seroprevalence of anti-hepatitis A virus differed by zone of residence (81.1% in rural area vs. 72.4% in urban area, p = .005) and increased significantly with lower level of education (p = .019). There was no statistical significant seroprevalence difference between male and female: 84.2% versus 85.2%, respectively. Our study confirm the transition pattern of the hepatitis A virus endemicity in Tunisia from high to intermediate and provide an evaluation of the hepatitis A virus epidemiological situation before vaccine implementation.

Attitudes towards plagiarism among academics of the faculty of Medicine of Tunis.

Assessing the extent of plagiarism within academics remains the first step in the fight against this behavior. The current study aimed to explore the attitudes of the Faculty of Medicine of Tunis (FMT)'s academics toward plagiarism. A cross-sectional study was conducted within the FMT during the 2018-2019 academic year. Data were collected using a questionnaire including the English version of the attitudes toward plagiarism questionnaire (ATPQ) which is composed of 29 statements divided into three attitudinal factors: positive, negative attitudes and subjective norms toward plagiarism. A total of 340 faculty members responded to the survey. The mean scores for both positive attitudes (28.8 ± 6.9) and subjective norms (24.6 ± 4.9) were between low to moderate and that of negative attitudes was moderate (22.4 ± 2.6). In multivariate analysis, participants with higher academic rank, those who had a good level of English or who attended English courses and those who attended workshops in scientific writing were less tolerant toward plagiarism. The implementation of courses on research practices as well as the introduction of medical English courses in the FMT's post graduate program could constitute relevant approaches to limit the extent of plagiarism.

Hepatitis viruses take advantage of traditional practices to increase the burden of hepatocellular carcinoma in Tunisia.

Hepatocellular carcinoma (HCC) is a major public health issue in Africa. In Tunisia, hepatitis B virus (HBV) is known to be an important risk factor for HCC in the south of the country, but the role played by hepatitis C virus (HCV) still remains unclear. The aim of the current case-control study was to identify risk factors for HCC development in the northern part of the country. Clinical and biological data including viral hepatitis status (serological and molecular) and non-infectious risk factors from 73 patients with HCC and 70 control subjects without hepatic diseases were collected. The mean age of the patients was 63 ± 10 years, and the ratio of males to females was 1.1. HCC occurred in cirrhotic liver in 72.0% of the cases. HCV infection was the dominant risk factor (64.3% of cases); the presence of HBV was observed in 53.4% of the cases. Occult hepatitis B and C were implicated, respectively, in 30.1% and 9.6% of the cases. HCV genotype 1b was predominant. Patients originating from western Tunisia formed a homogeneous group, characterized by significantly higher rates of tattoos or scarifications (83%) and HCV infection (80%) than those from other parts of the country. Chronic HCV infection is currently the primary risk factor for HCC in Tunisia; HBV infection remains frequent in its overt or occult infection forms. Traditional esthetic practices apparently contribute to increasing the burden of terminal liver diseases in western Tunisia.

Hepatitis C virus epidemiology in Central-West Tunisia: a population-based cross-sectional study.

This study aimed to assess the seroprevalence, viraemia and genotype distribution of hepatitis C virus (HCV) in a region in Central-West Tunisia. A door-to-door cross-sectional study was conducted on a randomly selected sample. A total of 3178 individuals aged 5 to 74 years and members of 935 families were investigated. Seroprevalence of HCV was assessed using ELISA tests. The viral load was determined by real-time RT-PCR, and HCV genotyping was conducted by amplification and sequencing in the NS5b genomic region. The global prevalence of HCV antibodies was 3.32% (95% confidence interval [CI]: 2.72-4.00). It was significantly higher in women: 4.47% vs. 2.16% in men, p = 0.001. Seroprevalence increased with age, and the highest rates were found in the 50- to 59-year-old age group (12.90%, 95% CI: 9.45-16.86), suggesting a cohort effect with very low contribution of intrafamilial transmission. Genotyping showed a predominance of subtype 1b (84.6%), with cocirculation of subtypes 2c (9.6%), 1a (1.9%), 1d (1.9%) and 2k (1.9%), similar to the previously reported genotype distribution in Tunisia and with no genetic clusters specific to the study region. These results indicate a higher endemicity of HCV infection when compared to the previously reported nationwide surveillance data. This study provides valuable data that can contribute to current strategies to eliminate hepatitis C.

Evaluation of the influenza-like illness surveillance system in Tunisia, 2012-2015.

BACKGROUND: This study was initiated to evaluate, for the first time, the performance and quality of the influenza-like illness (ILI) surveillance system in Tunisia. METHODS: The evaluation covered the period of 2012-2015 and used different data sources to measure indicators related to data quality and completeness, representativeness, timeliness, simplicity, acceptability, flexibility, stability and utility. RESULTS: During the evaluation period, 485.221 ILI cases were reported among 6.386.621 outpatients at 268 ILI sentinel sites. To conserve resources, cases were only enrolled and tested for influenza during times when the number of patients meeting the ILI case definition exceeded 7% (10% after 2014) of the total number of outpatients for the week. When this benchmark was met, five to 10 patients were enrolled and sampled by nasopharyngeal swabs the following week. In total, The National Influenza Center (NIC) received 2476 samples, of which 683 (27.6%) were positive for influenza. The greatest strength of the system was its representativeness and flexibility. The timeliness of the data and the acceptability of the surveillance system performed moderately well; however, the utility of the data and the stability and simplicity of the surveillance system need improvement. Overall, the performance of the Tunisian influenza surveillance system was evaluated as performing moderately well for situational awareness in the country and for collecting representative influenza virologic samples. CONCLUSIONS: The influenza surveillance system in Tunisia provided pertinent evidence for public health interventions related to influenza situational awareness. To better monitor influenza, we propose that ILI surveillance should be limited to sites that are currently performing well and the quality of data collected should be closely monitored and improved.