TB vaccine as anti-Covid candidate
- Posted By
10Pointer
- Categories
Science & Technology
- Published
21st May, 2020
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Context
- In a growing list of global trials on the efficacy of tuberculosis vaccines in preventing Covid-19, one is an upcoming 10-month trial being conducted by the Indian Council of Medical Research (ICMR) on the BCG vaccine.
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What is the BCG vaccine?
- Bacillus Calmette-Guérin (BCG) is a vaccine that uses a live attenuated strain (potency of the pathogen artificially disabled, but identifying characters retained) derived from an isolate of Mycobacterium Bovis.
- It has been used across the world, including in India for decades, against tuberculosis.
- India, like many other Asian, African, and Latin American countries, has a current national BCG vaccination policy for all at birth.
- Countries that have terminated their policies or only recommend the vaccine for specific groups are mostly in Europe and North America.
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What will the ICMR study focus on?
- It will focus on the vaccine’s potential in reducing the chance of Covid-19 death among those who are above age 60.
- The study will cover 1,450 elderly people in six red and orange zones: King Edward Memorial (KEM) Hospital, Mumbai; All India Institute of Medical Sciences (AIIMS), New Delhi; National Institute for Research in Tuberculosis (NIRT), Chennai; National Institute of Occupational Health (NIOH), Ahmedabad; National Institute in Environmental Health (NIREH), Bhopal; and National Institute for Implementation Research on Non-Communicable Diseases (NIIRNCD), Jodhpur.
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How this vaccine is affecting the COVID patients?
- The BCG vaccine has been studied in research on Covid around the world. A pre-print, population-level study by New York researchers in March suggested that countries with lower vaccination and without universal BCG vaccination (such as Italy and US) saw higher Covid-19 fatalities.
- The study compared this pattern to countries such as South Korea and Japan, which have standing policies on the topic.
- While these data could indeed suggest a protective effect of BCG vaccination, such studies cannot provide definitive proof of causality, owing to several inherent biases.
- A possible explanation is that children who have been vaccinated with BCG are less susceptible to infection with SARS-CoV-2 and so there is less spread of the virus to older populations, although this would need to be demonstrated.
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Are other countries looking into this?
- The World Health Organization (WHO) has initiated trials to ascertain the potential vaccine, but has not recommended it for Covid-19 prevention.
- Studies are ongoing in Australia, the Netherlands, Germany, the US, and several other countries.
- A recent study in the Journal of American Medical Association found no effectiveness of BCG vaccines in Israel, which used to have a universal policy and then shifted in 1982 to only vaccinate immigrants.
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What other ICMR studies are ongoing?
- One study seeks to assess the incidence of Covid-19 amongst healthcare workers who were taking the antimalarial drug hydroxychloroquine (HCQ) as well as any side effects from the drug’s use.
- Also, ICMR has been accepting applications nationwide to study the effectiveness of plasma therapy, which injects antibodies from a recovered patient into a severely ill patient.
- The Covid-19 National Taskforce had recommended the use of HCQ as a prophylaxis (protective and preventative) against Covid-19 infection for asymptomatic healthcare workers and asymptomatic household contacts of positive cases.
