Accordingly the study is for 10 months and when participants come into the study, they will be in it only for six months. So we need to complete our enrolment by the third or fourth month. The target sample size right now is about 1,450 for the BCG arm and 725 for the control arm. While participants under the BCG arm will be vaccinated, those under the control arm will not be given the vaccine. Both the arms will be observed for six months. It is going to be a 2:1 intervention to control study.
Because chennai has started the study first, initially the idea was to recruit 300-500 persons in each site. But it looks like we will be able to target around 500-700 persons in Chennai. The tamil Nadu government wants us to take in at least 1,000 for the study, but we will need to see. It is too early to talk about the nitty-gritty of the study right now. BCG is a tb vaccine. The efficacy of BCG is poor in adults against TB. It is good for children. However, the reason we are interested in BCG is that there have been plenty of studies over the past few decades, which have shown that BCG has a non-specific effect or a bystander effect. This effect boosts the immune response towards non-TB infections as well. For example, BCG promotes immune response against other viral infections.
So during these studies, when children were vaccinated, researchers found that apart from its response to tb infection, it also provided 50% less susceptibility to viral infections. This also means that a bacterial vaccination (BCG) promotes immune response to other viral infections, which are non-specific. The researchers also tested this on adults and the results were similar against flu and dengue. Finally, BCG was also tried on older people because they are highly susceptible to respiratory infections. It yielded promising results. That's why we are interested in BCG. The Hepatitis-B vaccine is given in india as a part of the Universal Immunization Program. There are still countries where there is no tb and hence the need to administer BCG does not arise. In those countries, the study groups have given BCG to a group and found out that this group has higher protection against viral infections.
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