Techno tracks

Emerging scenarios, new dilemmas

Published: Tuesday 31 January 2006

Techno tracks

New vaccines are creating new< The technology for developing new vaccines and the research that goes into it is becoming increasingly sophisticated and dependent upon an enormous corpus of funds to get off the blocks. This is raising important issues relating to pricing, access and international equity.

Take the flu vaccine -- an important product given the global scare over an impending avian flu epidemic. The old method for producing a flu vaccine involved injecting the virus into chicken eggs from where it could be harvested. This method was cumbersome, long-winded and unlikely to provide sufficient doses of vaccines to fight epidemics. Manufacturers are now trying to use cell cultures to grow the virus. Maintaining the infrastructure for storing and culturing cells is significantly more expensive. In this case, that's a price that has to be paid -- if the epidemic strikes.


The technological implications in the case of the dtp vaccine are slightly different. The older vaccine used cultured cells of the pertussis bacteria to make the vaccine. In the new process, the relevant antigen is extracted to make the vaccine. Though debated, the advantage of the latter is that it is safer. The disadvantage is that the process is more complicated and the vaccine produced thrice as expensive. The West has shifted to the acellular vaccine, but India, like most developing countries, still uses the older vaccine. But it can't be assumed that this situation will not change.

The case of hepatitis B is somewhat curiouser. It uses a 'renewable' resource -- yeast. The gene from the virus is introduced into the yeast. After that, the yeast continuously produces the antigen from which the vaccine is made. The basic raw material, in other words, is free after a point. You'd think that would make the vaccine cheaper. You would be wrong: defying economic logic, manufacturers are extracting superprofits on the grounds that this vaccine and technology is new.

Even technologies of administering vaccines are becoming more sophisticated. In the pipeline are heat-stable vaccines, jet injectors, aerosols and patches. These are crucial for India's delivery systems and indigenous investment into developing them are essential.

Long journey
Vaccines are substances containing a small amount of an inactivated or weakened disease-causing organism such as a virus or bacterium. Even antigens and toxins from microorganisms can be used to make vaccines. Vaccines work by inducing an immune response in people, which then protects them from infection for variable periods of time. In 1798, Edward Jenner, pioneered systematic vaccination using cowpox — a mild illness — against smallpox. The technique was then applied to other diseases by Louis Pasteur who found that weakened forms of microbes too could be used to produce resistance against disease.

Chronicle of conquest

How disease was taken down

Year Disease  

  Vaccine type

1798 Smallpox Live, weakened virus
1885 Rabies Inactivated virus
1897 Plague Inactivated bacteria
1923   Diphtheria Inactivated toxins
1926 Pertussis Killed, intact bacteria
1927     Tuberculosis (BCG) Live, weakened virus
1927 Tetanus Inactivated toxins
1935 Yellow fever Live, weakened virus
1945 Influenza Inactivated virus
1955 Injectable polio vaccine (IPV) Inactivated virus
1962 Oral polio vaccine (OPV) Live, weakened virus
1964 Measles Live, weakened virus
1967 Mumps Live, weakened virus
1970 Rubella Live, weakened virus
1981 Hepatitis B Conjugate viral product
1988 Chicken pox Live, weakened virus
1989 Typhoid Live, weakened bacteria

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