Inactivated vaccine against trivalent influenza: a comparative study of antigenicity by haemagglutination inhibition and simple radial haemolysis

A vacina inativada contra gripe, trivalente, preparada no Instituto Butantan, contendo 200 unidades hemaglutinantes de cada uma das cepas de virus Influenza A/SP/1/80 (H3N2), A/SP/1/78 (H1N1) e B/England/847/73, foi administrada em 110 voluntários humanos adultos, sendo que 62 receberam uma dose de vacina e 48 duas doses, com intervalo de 21 dias. A resposta de anticorpos específicos para influenza foi analisada comparativamente pelos testes de Inibição da Hemaglutinação (IH) e Hemólise Radial Simples (HRS). Ocorreu aumento significativo do teor de anticorpos nos indivíduos vacinados, correspondente a um aumento de 4 vezes ou mais nos títulos obtidos pelo teste IH e a um aumento de 3,0 mm ou maior no diâmetro das zonas de hemólise pelo teste HRS. Os métodos demonstraram correlação satisfatória entre si.The inactivated vaccine anti-influenza virus, prepared at the Butantan Institute, containing 200 U.H. from each one these virus strains, Influenza A/SP/1/80 (H3N2), A/SP/1/78 (H1N1), B/England/847/73, was administered to 110 human volunteers in one and two doses to 62 and 48 persons respectively, with an interval of 21 days between these doses. The response to specific antibodies to influenza was analysed comparatively by the methods of Haemagglutination-Inhibition (HI) and Single-Radial-Haemolysis (SRH). These methods demonstrated a correlation between themselves, with a percentual correspondence in the negative HI titres, < 1:20 and diameter of haemolysis < 3.0mm. Correlation between the haemolysis zone of 3.5-5.0 mm diameter with HI titres of 1:40-1:80 was observed and titres of 1:160-1:320 by HI test were equal to haemolysis zones of 5.5 mm in diameter by SRH test. Very high HI titres > 1:640, corresponded to hemolysis zones > 7.5 mm in diameter. Soroconversion rate occurred those vaccinated, which corresponded to an increase of 4 times or more in the antibody titres obtained from the HI test and an increase of 3.0 mm or more in the haemolysis zone diameter