The only clinically-approved tuberculosis (TB) vaccine — Bacille Calmette Guerin (BCG) — is given at the time of birth.
The efficacy of BCG vaccination in newborns is well known and has a documented protective effect against meningitis and disseminated TB in children, Dr Padma Priyadarshini, Director, ICMR’s National Institute for Research in Tuberculosis (NIRT) said.
However, scientists say there is considerable uncertainty on BCG revaccination. It is known that BCG revaccination enhances immune responses, but it is yet to be established if BCG revaccination can help prevent TB disease in household contacts, she said.
“The primary aim of this study is to assess the efficacy of BCG revaccination compared to oral chemoprophylaxis in preventing tuberculosis in household contacts of the same age group,” Dr Priyadarshini said.
A total of 9,200 children will be recruited across seven sites in India for the study.
The study is designed as a multicentre randomised controlled trial with two groups of healthy household contacts aged 6-18 years receiving either the BCG vaccine or oral chemoprophylaxis.
They will be followed up for 24 months to compare the incidence of TB in each arm.
As of now, there is no reported data of how many children develop the disease in this age group and how many die due to the disease, Dr Priyadarshini stated.
“We have got all the regulatory approvals. We are waiting for funds to be released. We are getting the sites ready. We hope to start the study before the end of this month,” she said.
According to official sources, the Indian Council of Medical Research (ICMR) has had one round of talk with the health ministry over BCG revaccination of adults, and another meeting is scheduled for next week.
All children will be household contacts of microbiologically confirmed pulmonary TB patients. Both C-Tb skin test positive and negative children will be included.
Similarly, both well-nourished and malnourished children will be included. All children will be followed up for 24 months post recruitment and the incidence of TB (all forms – PTB/EPTB) will be compared between the groups.
India has pledged to end tuberculosis by 2025, five years ahead of the global Sustainable Development Goals (SDG) target of 2030.