In silico comparative study of SARS-CoV-2 proteins and antigenic proteins in BCG, OPV, MMR and other vaccines: evidence of a possible putative protective effect.

BACKGROUND: Coronavirus Disease 2019 (COVID-19) is a viral pandemic disease that may induce severe pneumonia in humans. In this paper, we investigated the putative implication of 12 vaccines, including BCG, OPV and MMR in the protection against COVID-19. Sequences of the main antigenic proteins in the investigated vaccines and SARS-CoV-2 proteins were compared to identify similar patterns. The immunogenic effect of identified segments was, then, assessed using a combination of structural and antigenicity prediction tools. RESULTS: A total of 14 highly similar segments were identified in the investigated vaccines. Structural and antigenicity prediction analysis showed that, among the identified patterns, three segments in Hepatitis B, Tetanus, and Measles proteins presented antigenic properties that can induce putative protective effect against COVID-19. CONCLUSIONS: Our results suggest a possible protective effect of HBV, Tetanus and Measles vaccines against COVID-19, which may explain the variation of the disease severity among regions.

Epidemiological study of bacterial meningitis in Tunisian children, beyond neonatal age, using molecular methods: 2014-2017.

BACKGROUND: Since the 1990s, the epidemiology of bacterial meningitis worldwide has changed thanks to vaccination. In Tunisia, the main causative pathogens were Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae serotype b (Hib). Only Hib vaccination was available during our study period. OBJECTIVES: We performed a laboratory case report based-study of suspected bacterial meningitis in Northern Tunisia from January 2014 to June 2017. METHODS: CSF samples obtained from children beyond neonatal age with suspicion of meningitis were tested by two real time PCRs, targeting pneumococcus, meningococcus and Hib, and conventional methods. RESULTS: Using real-time PCR, 63 were positive including ten supplementary cases compared to conventional methods. A general decrease of bacterial meningitis cases was demonstrated comparing to previous data. Pneumococcus was predominant (69.84%) followed by meningococcus (28.57%) and Hib (1.59%). The main serotypes were 14, 19F, 6B and 23F for pneumococcus and serogroup B for meningococcus. Most cases occurred during cold season and children under one year were the most affected by bacterial meningitis. CONCLUSION: Our study suggests the predominance of pneumococcal cases. It may provide valuable data on meningitis epidemiology before the introduction of pneumococcal vaccine, which may be useful for future evaluation.

Molecular diagnosis of bacterial meningitis by multiplex real time PCR in Tunisian children.

INTRODUCTION: Bacterial meningitis is a medical emergency requiring a fast and reliable diagnosis. Molecular methods such as real-time PCR (rt-PCR) offer an attractive alternative. Thus, this study aims to establish multiplex rt-PCRs detecting N. meningitidis, S. pneumoniae and H. influenzae b from cerebrospinal fluid in Tunisian children beyond neonatal age. METHODOLOGY: Using bioinformatic tools and experimentation, we validated the specificity and optimal criteria of PCRs for primers and probes of plyA (S. pneumoniae), ctrA and sodC (N. meningitidis) and bexA genes (H. influenzae b). We performed one multiplex RT-PCR for detection of S. pneumoniae and N. meningitidis targeting plyA and ctrA, sodC genes respectively, simultaneously with a singleplex RT-PCR for H. influenzae b. The sensitivity and specificity of our methods were assessed. Then, we tested our methods for 122 CSF samples collected from suspected meningitis cases between 2014 and 2016 in Bechir Hamza Children's Hospital of Tunis. RESULTS: Our results have shown the sensitivity of the designed PCRs was up to 10-4 DNA dilution and the specificity was 100%. PCR evaluation has shown 51 positive samples: 38 of pneumococcal cases, 12 meningococcal cases, 1 case of H. influenzae b with 8.57% and 50% of supplementary positive cases rates respectively. CONCLUSIONS: Our assay proved to be very sensitive, specific and rapid for bacterial meningitis diagnosis. In the recent context of Hib vaccination, the possibility of detecting S. pneumoniae and N. meningitidis separately constitute an attractive opportunity. Nevertheless, simultaneous detection of Hib remains relevant in specific clinical context and for epidemiologic study.