Since December 2019, COVID-19, caused by the novel coronavirus SARS-CoV-2, has spread to more than 223 countries to date causing huge health and economic crisis [1,2,3]. The genome of SARS-CoV-2, like other families of Coronaviruses (CoVs), is an enveloped positive-sense single-stranded RNA virus. It belongs to the Coronaviridae family, the Orthocoronavirinae subfamily and the Betacoronavirus genus [1,2,3]. Coronaviruses (CoVs) can mainly infect mammals by Alpha (α) or Beta (β) coronaviruses, and predominantly can infect birds by Gamma (γ) or Delta (δ) Coronaviruses [4, 5]. The SARS-CoV-2 viral genome of 29,903 nucleotides, approximately, contains 5’and 3’ untranslated regions and 11 Open Reading Frames (ORFs) encoding 11 proteins including the S protein . Probably, the modes of SARS-Cov-2 transmission among humans are via three primary pathways: inhaling respiratory droplets directly from infected persons, or contact with infected environmental surfaces know as “fomites” and touching your mucous membranes with soiled hands, or inhaling infected airborne particles. Recent researches indicate a high correlation between the SARS-COV-2 genome and the two genomes of the bat-CoV RaTG13 and the pangolin-CoV MP789 followed by two other genomes: CoVZC45 and CoVZXC21 [7, 8].
The outbreak of SARS-CoV-2 caused 2,797,435 deaths with a total of 127,847,262 confirmed cases (December 20, 2019 to March 29, 2021) that have variable damages from one country to another. In the majority of cases, huge damages were reported, such as in the USA, Brazil, and India causing respectively 562,526, 312,299 and 161,881, deaths as well as 30,962,803, 12,534,688, and 12,039,644 confirmed cases up to 29 March 2020  Nevertheless, in other regions, such as, Laos, Vietnam, and Finland damages seem to be limited and the number of deaths, respectively, did not exceed 0, 35, and 822 . However, for other regions, like, Nicaragua, Sierra Leone, Vietnam, and Madagascar, cases and damages seem to be limited and the number of deaths, respectively, did not exceed three hundred cases. These temporal variances in a number of case fatality rates can be caused by different factors: political and economic strategies, cultural behavior, age, and also health infrastructure, [10, 11]. Furthermore, the population’s immunological background is probably due to the vaccination strategies used in these countries [11,12,13,14,15]. From another point of view, different vaccines such as BCG (Bacillus Calmette-Guérin), OPV (Oral Poliovirus Vaccine), and MMR (Measles, Mumps, and Rubella vaccines) demonstrated an immune response to fight various pathogens [12, 14, 16, 17].
On the other hand, these different variations may be attributed to the adoption of a universal and long-standing BCG as again found to be very significantly protective for whom vaccination records were available [11, 18, 19]. In addition, the MMR vaccine protective potential was investigated based on S protein bioinformatic analysis . Based on this computational biology analysis, the MMR vaccine was investigated as being potentially protective for adults and provides advantageous protection for children against COVID-19 as well. However, experimental analysis is required. Furthermore, pneumococcal vaccination PCV13 was again found to be very efficient in a study of 137,037 individuals who received SARS-CoV-2 PCR tests . A recent study proves great similarities between the SARS-CoV-2 genome and pneumococcal vaccines PspA and PspC . Indeed, other researchers found that polio, Hemophilus influenzae type-B (HIB), varicella, geriatric flu, MMR, PCV13, and hepatitis A / B (HepA-HepB) vaccines administered in the past 1, 2, and 5 years are associated with decreased SARS-CoV-2 infection rates [22, 23].
In this work, we propose in silico study to investigate the potential protective effect of 14 investigated vaccines (Bordetella Pertussis, Tetanus, Haemophilus influenzae type B (Hib), Corynebacterium Diphtheriae, Streptococcus pneumoniae, Hepatitis A, and Hepatitis B) against COVID-19. We aim to localize similar amino acid (aa) regions in the S protein of the SARS-CoV-2 genome and the main antigenic proteins in other vaccines which may lead to the production of cross-reactive antibodies against the target viruses as well as SARS-CoV-2. To achieve this goal, we used a combination of bioinformatics, and signal processing tools to identify the common amino-acid (aa) sequences of the main antigenic protein of SARS-CoV-2 and investigated vaccines.