BIOLOGICAL CHARACTERISTICS OF BCG VACCINE PRODUCED AT PASTEUR INSTITUTE IN HOCHIMINH CITY FROM 1990 TO 2000

 

Mai Nguyet Thu Hong1, Tran The Trong1, Tran Thi Thao1, Lam Thi To Nga1, Tran Nguyen Van Anh1, Hoang Kim Loan1, Ly Phi Phuïng1, Tran Thanh Son1, Ha Ba Khiem1, Nguyen Thi Hoi1,
Truong Thi Xuan Lien1,  Doan Thò Tam2, Pham Duy Linh3, Le Hoang San4, Nguyen Nhu Mai4.

Marina Gheorghiu5, Lagranderie Micheline5, Gilles Marchal5.

1Pasteur Institute in HCM City, 2 National Center for Vaccine and Medical Products Quality Control

3 Pham Ngoc Thach Tuberculosis and lung diseases Center,
4 Medicine Preventive Center of TienGiang Province
, 5Pasteur Institute in Paris

 

BCG vaccine is the only vaccine with the others methods for tuberculosis prevention such as: improving of environment hygiene, resistant enhancement to tuberculosis in high risk group, good management and separation of tuberculosis patients. Since, the observation of the characteristics of this vaccine is very necessary, specially, the long period observations.

This study observed the characteristics of BCG vaccine produced in Pasteur Institue of HoChiMinh city from 1990 to 2000. This was the period that the Minister of Health and “Amico-Amitié Franco-Vietnamnienne” decided to set up a new BCG laboratory, and at that time, this BCG laboratory had been received the technical transmitting of BCG vaccine production from Pasteur Institute of Paris.

In ten years of production, with 2 to 4 million of doses per year, the vaccine responds to the requirements of Viet Nam and also of WHO.

-         The in vitro test demonstrated that the viable counts varied from 2 to 3 millions colony forming units per mg of vaccine. The opacity at 490 nm varied from 0.185 to 0.249 and the diffusion index of vaccine varied from 1.16 to 1.37.

-         The in vivo test showed that the 510 vaccine lots were not absolutely toxic and had a good effectiveness in 6120 guinea pigs.

-         Vaccine gave good immunity and the low secondary reaction in human. 94.11% of newborns and 100% of children up 3 months had an immunity after vaccination. 60.25% of these individuals remained this immunity in 5 years and 60.10% in 10 years.

-         The lymphadenitis suppurative rate was 0.98% in newborns and 0% in children up 3 months.

-         The positive transfer reaction after BCG revaccination was high. 52.11% before revaccination and 96.17% after revaccination.

-         Not any secondary reaction or complication was observed, even in the sensitivity to tuberculin individuals before revaccinatin.

-         Vaccine had a good protection. 89.72% of newborns in HoChiMinh city had an protective ability against to tuberculosis after BCG vaccination (a report of Tuberculosis and Lung diseases Center from 1989 to 1993 in 76459 newborns in HoChiMinh city).

-         An molecular observation demonstrated that the BCG had the IS 6110 gene. This was the specific sequence of M. tuberculosis complex. This structure was similar to the other observations had been published.

These results demonstrated that the BCG vaccine produced in Pasteur Institue of HoChiMinh city from 1990 to 2000 responded to the requirements of Viet Nam and WHO, gave a good immunity and a low rate of secondary reaction. With these characteristics, vaccine can be used in regional and in national tuberculosis prevention program when necessary