#Thread on brief history of BCG vaccination in India and why researchers are touting it as an intervention that could possibly prevent a huge death toll in India and other countries with universal BCG vaccination program.
Mycobacterium tuberculosis which causes TB been with us for over 70,000 years and adds approx 10 million cases/yr. It finds its mention in biblical books and has bn verified in Egyptian mummies. 1st documents describing TB, date back to 3300 and 2300 yrs in India and in China. 
The disease has been known by various names through history like "Pthisis","King's Evil","Robber of youth", "Consumption","White Plague" ,"Captain of all these men of Death" and has killed millions. Johann Lukas Schönlein coined the term "tuberculosis"
The bacteria Mycobacterium tuberculosis was first isolated by the German doctor Robert Koch who also gave it its name. He published his work in an article called " The Etiology of Tuberculosis" in 1882.Since then the bacteria has been also been called as Koch's Bacillus.
Fresh air & sanatoriums were the only effective treatment known to TB till BCG vaccine was developed by Albert Calmette & Camille Guerin in Pasteur Institue, Lille, France from 1908-1921.They grew bovine strain of the bacteria (obtained from infected cows) in potatoes & glycerin.
They subcultured the bacteria multiple times to get a weak strain which could not cause the disease but retained its ability to trigger an immune response.After 230 subcultures they named the strain Bacille Bilie Calmette-Guerin; later they omitted "Bilie" and so BCG was born.
The first dose of BCG was given orally to an infant whose mother had died of TB in 1921.Oral BCG vaccination continued till intradermal injections of the vaccine started by Swedish paediatrician Arvid Wallgren became popular in 1950s.
Lubeck Disaster:In 1930, Lübeck,Northern German city, a 250 newborn babies were vaccinated. 73 died in the first year. BCG was supplied from the Pasteur Institute, Paris but prepared for administration in the tuberculosis laboratory in Lübeck and the oral route was used.
Four to six later a large number of the infants developed TB. Some recovered. Though the incident was later attributed to negligent contamination of vaccine by virulent tubercle bacilli in the Lübeck laboratories, it greatly reduced the confidence of population in the vaccine.
In India, the govt in May1948 cited the Bhore Committee report and issued a press note stating that TB had assumed "epidemic prportion" and decided to run BCG vaccination program on a small scale. A BCG vaccine lab was set up in Kings Institue, Guindi, Tamil Nadu by Aug 1948(pic)
A pilot project of BCG vaccination was started the same year with help of International Tuberculosis Campaign (ITC) at Madanapelle town by the United Mission Tuberculosis sanatorium(UMTS). Dr Frimodt Moller was its supervisor. He also trained TB workers and took TB surveys,
The project was extended to various schools of Madanapalle by five teams of ITC who trained TB workers till 1951. ITC supported Indian BCG program till June 1951. Thereafter a large scale project of vaccinating young population was carried by GOI in collaboration with UNICEF
In 1955-1956, the BCG vaccination mass campaign covered all the States of the Indian Union. BCG vaccination became a part of the National Tuberculosis Control Programme (NTCP), which was started in 1962.
To check the effectivity of BCG program in India a 15 year long trial of the vaccine was conducted in Chingleput district of Tamil Nadu starting in 1968. A total of 3,60,000 people were administered 2 stains of the vaccine ( madras strain and paris strain) and a placebo.
Great Madras Failure: The study showed that no protection was offered by the vaccine against adult onset tuberculosis as incidence of adult tuberculosis was found to be the almost same in all the three groups.
This result shook not just India but the entire world. Major revisions were made. As the vaccine did offer protection against childhood tuberculosis like tubercular meningitis and miliary TB, it was therefore decided to restrict BCG vaccination to newborns & and infants only.
At present, BCG vaccine in india is only being administered at birth and has a protective effect of about 10 years. Booster or repeat doses are not recommended as there is no evidence of it offering any added protection
BCG vaccination and COVID19: The present day studies are based on comparative data of no of deaths due to COVID19 from countries with and without universal immunization against tuberculosis. With data showing lower no of deaths in countries with nationwide BCG program.
Further data comparison showed even lower death rates in countries where BCG immunisation is given at birth.Pic 2 shows comparison between two neighboring countries, Spain and Portugal.Portugal with universal BCG program shows much lower death rates.
Various possible explanations of this protection are being mentioned in the studies. One of them is trained immunity i.e the bacterial strain in the vaccine brings epigenetic changes or reprograms monocytes ( cells that fight invading pathogen) to fight against viral infections.
Another postulate says that vaccination from BCG upregulates secretion of mediators of inflammation like interleukin1B which offer protection from viral infections.
As the infection would take its natural course through our country with universal immunization against TB for a long time (over 60 years), one can hope the no of fatalities are low in view of the current trends in rest of the world.
In a report published in daily mail Australia has already launched a randomised trial on 500 of its health staff in South Australia to verify its potency in adults against COVID19
dailymail.co.uk/news/article-8…
dailymail.co.uk/news/article-8…
Prof Madhukar Pai @paimadhu , Director McGill Health programs and international TB centre, an eminent epidemiologist has explained the shortcomings of these ecological studies and how we should not jump to conclusions.His thread is a must read.
Found this piece from @PIB_India archives when GOI decided to implement BCG vaccination in India. Not a one man job. We would have been nowhere had WHO and ITC not helped us..
Beautiful article on how the scandinavian ITC in collaboration with UNICEF helped set up BCG campaign and fight against tuberculosis in India @DenmarkinIndia @IndiainDenmark
muse.jhu.edu/article/217158
muse.jhu.edu/article/217158
#4-6 weeks later.
WHO does nt recommend BCG for "prevention" from COVID19 infection nd hs asked to await results of trials being conducted.Question is whether the vaccine helps n infected prsn fight the infection better or not as it is d mortality rates that hv bn compared.
who.int/news-room/comm…
who.int/news-room/comm…
WHO is doing its part by clarifying that BCG does not protect from getting "infected" by the virus as those r the kind of rumours that r being spread.The studies have compared the mortality rates, not the no of cases & hv suggested that d vaccine helps fight the infection better.
