In developing countries because of poor compliance, poverty, ignorance, primary and secondary prevention strategies are difficult to implement properly. Also in western countries (USA), where there is resurgence of ARF, interest in vaccine development has appeared. However, there are quite a few technical problems in development of vaccines. There are 2 types of vaccines.
I) Vaccines Against Virulence Factors Conserved Amongst Various GAS Despite antibodies to these conserved antigens, people are affected by multiple serotypes of GAS. Hence there remains a doubt regarding the protective efficacy of antibodies against GAS infections.
II) Vaccines Based on Type Specific, Hypervariable N-terminal Regions of M Proteins Life long immunity which is protective (25 to 30 years after infection) is achieved by antibodies against the hypervariable N-terminal of M-Protein. Considering this fact, using recombinant DNA technology, synthetic peptide copies of the hypervariable N-terminal of the M-protein are being manufactured. These synthetic peptides produce only bacterial antibodies without host cross-reactive antibodies. Currently N-terminal synthetic peptides of multiple serotypes of GAS are linked to a carrier protein to produce opsonizing antibodies. Tetra, hexa and octavalent vaccines incorporating M 1, 2, 3, 5, 6, 18, 19 and 24 N-terminal peptides are being evaluated in animals.