Can India, with highest burden of TB, be free of it by 2030?

March 24 is World Tuberculosis Day. It was on the evening of this day 136 years ago in 1882 that Robert Koch, a German physician and scientist, announced at the Berlin Physiological Society that he had discovered the bacteria that caused tuberculosis and it was named Mycobacterium tuberculosis. It was for this great discovery that in 1905 he received the Nobel Prize.

Subsequent to the discovery of the bacterium, 38 years later, in 1920, two French scientists Albert Calmette, a microbiologist, and Camelli Guerin, a veterinarian, discovered the vaccine for tuberculosis. They worked hard for almost 13 years before they could evolve tuberculosis bacteria that were not virulent (not active), cultivating it over 239 iterations. It was this inactive bacteria that would not cause the disease but would help produce antigens in the body when injected into humans. These antigens developed by the body would attack and kill the tuberculosis bacteria if and whenever they attacked the body.

There was much enthusiasm about the discovery and recognising the contribution of the two scientists, the vaccine was aptly named after them as BCG (Bacilli Calmette and Guerin). But the enthusiasm was short-lived, when 72 infants died after they were administered contaminated BCG vaccine. The vaccine went into cold storage, to be retrieved only in 1945 after World War II.

The BCG vaccine was introduced in India in 1948. It is now for 70 years that this vaccine has been administered to every newborn. It is time to relook and reflect. The vaccine faced odds even before it was initiated as there was no consensus among public health experts regarding its benefits. Halfdan Mahler, serving as the senior WHO officer to the BCG campaign in India from 1951 to 1955, complained that part of the tuberculosis problem lay in the fact that the disease was "such a nice, unspectacular killer".

In its true sense, the BCG vaccine has failed to achieve any remarkable success in reducing mortality. The expectation of the people and the scientists was high from BCG vaccine, particularly after small pox was eradicated globally by 1975 just by using the vaccine for it. The same was expected of the tuberculosis vaccine, too. But that did not happen. On the contrary, the BCG vaccine was caught up in controversies.

In fact, there are arguments both for and against this "naughty" vaccine. Some experts believe that, at the very least, it prevents tuberculosis of brain and extensive tuberculosis of the lung, known medically as meningitis and miliary tuberculosis respectively. But others vehemently argue that BCG does no good and, in fact, hinders diagnosis of tuberculosis. Unfortunately, it is not easy to prove the number of people in whom the BCG vaccine could have prevented brain and lung damage. So, while the heated debate continues, without throwing much light on the matter, it is time to examine what other countries have done.

Taking a stand

A few countries that have accomplished victory over tuberculosis as a public health problem have never ever used BCG vaccine. Notable among them are America and the Netherlands. Several other developed countries like Germany, UK and several Western European countries have also given up BCG since long for the reason that the BCG vaccine is not "cost effective". India perhaps needs such a study to take a firm stand on the BCG vaccine. The World Health Organisation (WHO) has said that "While BCG has demonstrated significant effectiveness, protection has not been consistent against all forms in all age groups."

Another very interesting tool to detect tuberculosis was discovered and came to be known by various names, but most popularly as the 'Tuberculin test'. In this test, a protein extract of the bacteria is injected into the body and observed for 48 hours. If the individual tests positive, s/he has tuberculosis. So, the test may be exclusively used for detecting tuberculosis and is no aid in treating it. Though the reaction was described by Robert Koch himself in 1890, it remained unused till 1939, when Charles Mantoux, a French physician, continued Koch's work.

Just note that the BCG vaccine became widely and globally available six years after the tuberculin test was founded. It was during this period that many countries that have now conquered tuberculosis worked exhaustively by using the tuberculin test. Those that tested positive were isolated, and those who were in contact with them, too, were tested. Despite the fact that the test had a few inherent problems, like that it cannot be used on individuals with reduced immunity, it offered several advantages in that it was affordable, simple to use and could be done at the doorstep of the individual.

The medicines to treat tuberculosis, like Streptomycin, became available in 1944, five years after the tuberculin test did. So, it is obvious that the tuberculin test became a useful and powerful tool in many developed countries to detect, isolate and thus prevent suffering and death from tuberculosis.

As per WHO, "Globally, 1.7 billion people are estimated to be infected with M. tuberculosis and, in 2016, 1.7 million people died from TB, including 4,00,000 among people infected with HIV". India has the highest burden of TB. The WHO's TB statistics for India for 2016 give an estimated incidence of 2.79 million TB cases in the country. That is, 2.79 million people newly contracted the diseases in just that year.

These numbers and facts from the pages of history are a wake-up call for action to achieve the stated goal of "TB-free" status by 2030. Is India ready?

(The writer is president, Drug Action Forum, Karnataka)