CME INDIA Presentation by Admin.
Recently some newspapers highlighted the unique research from Pune, saying that a single shot of BCG vaccine when given to COVID-19 cases, improved oxygen saturation and other parameters. What is the lesson learnt?
What is this Study?
- November 5th 2020: Source: Revealed on a pre-print server /Not peer-reviewed.
- Newspapers carry a story based on a trial by Parel’s Haffkine Research Institute and BJ Medical College, Pune.
- It was conducted on 60 COVID-19 patients.
- These were hospitalized with breathlessness and pneumonia. (having an oxygen saturation of lower than 94% or much less and had radiologically confirmed pneumonia)
- The study says that a reduction in oxygen requirement from 3rd or 4th day and improved x-rays and CT scan from day 7-15 has been found.
- There were no deaths in the arm that got the BCG shot while there were two deaths in a group that got a standard line of care.
- The period of hospitalisation within the vaccinated arm was a mean of seven days.
- It didn’t trigger any adverse reaction in adults stated even individuals who weren’t vaccinated in childhood confirmed quicker restoration.
- It is claimed that a single shot of the BCG vaccine might resolve breathlessness and stop severity in moderate to severe cases.
- “Our study showed key improvement in oxygen saturation status within 3-4 days and faster resolution of pneumonia in vaccinated group, implicating localised effects in the lung and innate immunity” – Dr Usha Padmanabhan, lead researcher from Haffkine (TOI).
- This study just gives a hint that BCG can be useful in therapy too.
The Haffkine Institute
- The oldest biomedical research institutes in the country.
- Established 1899.
- Named after the scientist (Dr Waldemar Mordecai Haffkine) who invented the plague vaccine.
- Discovered by Albert Calmette, a French physician and bacteriologist, and his assistant Camille Guérin, (Lille, France) in 1908.
- The BCG strain was isolated after subculturing 239 times during 13 years from virulent strain on glycerine potato medium.
- The research continued throughout World War I until 1919.
- When the now avirulent bacilli were unable to cause tuberculosis disease in research animals. Calmette and Guerin transferred to the Paris Pasteur Institute in 1919.
- The BCG vaccine was first used in humans in 1921.
- The University of Exeter is leading the UK arm of the trial, called the ‘BCG vaccination to Reduce the impact of COVID-19 in healthcare workers.’ The UK joins study centres in Australia, the Netherlands, Spain, and Brazil in the largest trial of its kind.
Some Observations do Favour
- The impact of the disease is different in different countries. These differences are attributed to differences in cultural norms, mitigation efforts, and health infrastructure.
- Countries such as Spain, France, and Switzerland, have discontinued their universal vaccine policies due to comparatively low risk for developing M. bovis infections as well as the proven variable effectiveness in preventing adult TB; countries such as the United States, Italy, and the Netherlands,
- Trained immunity: It is caused by metabolic and epigenetic changes leading to promotion of genetic regions encoding for pro-inflammatory cytokines.
- BCG vaccination significantly increases the secretion of pro-inflammatory cytokines, specifically IL-1B, which has been shown to play a vital role in antiviral immunity.
- The correlation between the beginning of universal BCG vaccination and the protection against COVID-19 suggests that BCG might confer long-lasting protection against the current strain of coronavirus.
- BCG is generally innocuous with the main side effect being the development of inflammation at the site of injection.
- BCG is contraindicated in immune compromised people as well as pregnant women.
Some Points to Ponder
- The heterologous immunity induced by BCG has predominantly been shown to last for < 2 years.
- Since BCG vaccination is predominantly administered to infants and children, BCG-associated heterologous immunity may not be responsible for reduced COVID-19 morbidity in adults and the elderly.
Miller et al., 2020.Study Highlights:
- Correlation between universal BCG vaccination policy and reduced morbidity and mortality for COVID-19: an epidemiological study. medRxiv pre-print.
- The important take-away is that BCG’s protective effect fades over time. So, it is not clear how a vaccine that offers protection early in an individual’s life would protect individuals against COVID-19 once they are of an advanced age.
CME INDIA Learning Points
- Although this study looks exciting, it is not peer-reviewed. Sample size is small.
- Results are said to be inconclusive by some experts
- At best, it needs to be confirmed by well-designed, large randomized studies.
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