Coronavirus Disease 2019 (COVID-19) is a viral pandemic disease that may induce severe pneumonia in humans. The variation in the number of deaths and infections among countries can be explained by different factors, such as health infrastructure, mitigation strategies, and also cultural behavior.
The immunological background of the population, mainly due to the vaccination strategies used in those countries was also suggested. Indeed, it was previously demonstrated that administration of attenuated vaccines such as OPV (Oral Poliovirus Vaccine), MMR (Measles, Mumps and Rubella vaccines), and BCG (Bacillus Calmette-Guérin) vaccines could improve the innate immune response to fight different pathogens.
Furthermore, it was suggested that the adoption of a universal and long-standing BCG policy may have a protective effect against COVID-19.
In the frame of the PHINDaccess project, researchers from the Institut Pasteur de Tunis in partnership with Tunisian collaborators carried out an In silico comparative study of SARS-CoV-2 proteins and antigenic proteins in BCG, OPV, MMR, and nine inactivated vaccines (Tetanus, Corynebacterium diphtheriae, Bordetella pertussis, Hepatitis B, Hepatitis A, Haemophilus influenzae type B (Hib) and Streptococcus pneumonia vaccines (PCV10)).
The aim of this study is to identify similar amino-acid patterns in all SARS-CoV-2 proteins and the main antigenic proteins of the above-mentioned vaccines and to predict their immunogenicity, using a combination of bioinformatic tools. The results will help understanding the variation of the disease severity among regions and may also contribute to strengthening the international immunization strategy. This study constitutes a way to confirm the effectiveness of the BCG vaccine to fight against the covid-19.
Sequences of the main antigenic proteins in the 12 investigated vaccines and SARS-CoV-2 proteins were compared to identify similar patterns. Then, the immunogenic effect of identified segments was assessed using a combination of structural and antigenicity prediction tools.
Based on information collected from public bibliographic databases, NCBI Genbank database, and RCSB, authors used Blastp ( Basic Local Alignment Search Tool protein), BioEdit software, EDB analysis resource Bepipred 2.0, IEDB analysis resource NetMHCpan and freesasa for the structural and antigenicity prediction analysis. This analysis used PHINDaccess’s servers in the Institut Pasteur de Tunis.
The authors identified a total of 14 highly similar segments 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.
They concluded that 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.
In contrast, Tetanus, Mumps, Hepatitis B and BCG antigenic proteins showed no more than one similar segment with SARS-CoV-2 proteins.
Currently, to support the In silico association between Measles, HBV, Tetanus, and Covid-19 severity, the research team is assessing large epidemiological study.