Vietnam successfully studied influenza A / H5N1 vaccine and influenza A / H1N1

The self-production of domestic flu vaccines, Vietnam can be more proactive and timely in preventing pandemic influenza in the future.

Epidemiologic experts say the epidemiological characteristics of influenza A are high in morbidity and mortality, with a high incidence and death rate, as a result of antigenic alterations - substitution potential of the new haemaglutinin antigen (with or without neuramidase antigenic changes) in a population without prior immunization.

Pandemic and antigenic changes are unpredictable and do not occur regularly. At least four pandemics occurred in 1918 (A / H1N1), 1957 (Asian A / H2N2 flu) and 1968 (Hong Kong A / H3N2 flu) and the latest is the 2009 A / H1N1 pandemic.

With the epidemic situation of influenza A virus in the world as well as Vietnam is still happening very complicated, along with the habit of raising poultry right at home, the risk of outbreaks of influenza in Vietnam is very great. With the successful study of the flu vaccine production process, it has very practical meaning, contributing to proactively preventing epidemics and avoiding spreading in the community.

Vaccine production with reverse genetics

Immediately after influenza A / H5N1 virus was isolated in patients in Vietnam, Vaccine Company and No. 1 biological product (VABIOTECH) conducted research to develop influenza A / H5N1 vaccine. With the efforts, creativity of scientists in the company and international cooperation with many prestigious organizations in the world, the process of producing A / H5N1 influenza vaccine on monkey kidney cells has been studied. Successfully rescued, the first series of experimental vaccines have also been produced and clinical trials have yielded very positive results.

The company created the strain that produced the rg-H5N1 vaccine by reverse genetics. In this study, the plasmid system was used as 12 plasmids, including two plasmids carrying the haemagglutinin (HA) and neuraminidase (NA) genes of the H5N1 virus (A / Vietnam / 1194/2004), in which the HA gene was eliminated. removing the gene part related to viral toxicity; 6 plasmids carry the remaining 6 genes of influenza A / PR / 8/34 virus; 4 plasmids carry influenza virus gene A / PR / 8/34 expressing 4 assistive proteins.

Along with his creations, applying to the specific situation in Vietnam, the strain of rg-H5N1 virus is created by reverse genetics with the cooperation of Dr. Yoshihiro Kawaoka, Tokyo University of Japan. by infecting plasmids into monkey kidney cells to initiate and rehabilitate the newly recreated rgH5N1 virus on primary and later monkey kidney cells that are adaptable to primary monkey kidney cells with a high titre for future vaccine production is effective. This is the first study in the world according to this technique.

The VABIOTECH influenza vaccine production process is developed based on cell culture, different from the traditional production technology produced on chicken eggs with embryos. With the use of primary monkey kidney cells (PMKc) for the production of influenza vaccines has advantages over existing technologies. PMKc cells are very suitable for many different strains of influenza virus, which can meet the annual change in the influenza virus strain producing the vaccine in accordance with the recommendation of the World Health Organization.

Unlike chicken eggs with embryos, PMKc cells can be used to multiply highly virulent influenza viruses like the A / H5N1 strain of bird flu. This is also a primary cell, so flu vaccine production technology is simpler than the production technology of embryonic chicken eggs (requiring removal of chicken egg Albumin) and on MDCK permanent cells and Vero (requires type remove AND cells).

PMKc cells that have been used to produce other vaccines that have been commercialized and widely used for people like polio vaccine and hepatitis A vaccine have shown to be highly safe. In particular, using PMKc cells can take advantage of the input materials that are available in Vietnam Maccaca Mulatta monkeys (Ro island in Quang Ninh is a place for Maccaca Mulatta monkeys to serve vaccine production).

A / H5N1 influenza vaccine is a safe product

Vaccine Company and No. 1 biological product (VABIOTECH) confirmed 6 series of A / H5N1 influenza vaccines and 3 types of A / H1N1 flu vaccines that have been tested and tested at the laboratory scale and tested for quality. Standards required for developing a World Health Organization flu vaccine. The results show that all series meet the standards for a flu vaccine in general safety, thermo-lice, efficacy (SRID), chemical composition, physical and chemical properties .

Accordingly, A / H5N1 influenza vaccine has completed clinical trials phase I, II and is being conducted in phase III. The results of phase I and II showed that influenza A / H5N1 vaccine (FLUVAX) produced by VABIOTECH, safe on volunteers, did not cause serious unwanted reactions, mainly just pain at the injection site. Over and over after 24 hours without treatment. Biochemical indicators in volunteers after vaccination are normal. The vaccine produced by A / H5N1 influenza according to technology has resulted in a good immune response in 100% of subjects vaccinated from 7.5mcg or more, meeting European standards.

Particularly, the A / H1N1 pandemic vaccine has ended the pre-clinical study and is preparing the application for permission from the Ministry of Health to conduct an assessment on clinical field in 2012.

With the results achieved, the project "Research on production of influenza A (H5N1) vaccine and influenza A (H1N1)" of the Vaccine and Biologicals Company No. 1 has been recognized by the Ministry of Health as one of 26 medical achievements. , outstanding medicine. In particular, with self-production of domestic influenza vaccines, Vietnam can be more proactive and timely in preventing pandemic influenza in the future, without being too dependent on foreign-supplied vaccines. Successful research in the production of domestic flu vaccines also helps reduce the cost of flu vaccines, helping to increase the number of people who have access to influenza vaccines.