New BCG-based TB vaccine-VPM1002
Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis. Tuberculosis infection can be of two kinds-latent and active. Latent tuberculosis is not contagious and do not show any symptoms since the bacterium remains inactive in the body. Latent tuberculosis can become active tuberculosis in those people who have weak immune system especially in those with HIV and in those who smoke. Active TB gets transmitted through air when people with active TB cough, sneeze, spit and speak. Tuberculosis affects mainly the lungs of a person, but it can also affect other parts of the body.
What is VPM1002?
VPM1002 is the newly developed TB vaccine which is based on the BCG vaccine which is in use as of today. It is a recombinant BCG (bacillus Calmette-Guérin) vaccine and contains genetically modified mycobacterium bovis bacteria. In this vaccine, a gene in the existing BCG vaccine has been exchanged to increase its immunogenicity. This built-in gene makes the vaccine to get easy recognition from the cells of the immune system and protects the organism against the actual infectious tuberculosis pathogens.
VPM1002 was developed at the Max Planck Institute for Infection Biology, Berlin. This vaccine has been sub-licensed to the Pune-based Serum Institute of India Limited.
Why is a new TB vaccine needed?
Search for an improved TB vaccine is more than 90 years old. Bacillus Calmette-Guerin (BCG) is the only available licensed vaccine to fight against TB, which was developed in the early 20th century. BCG was first used in 1921and has become the most widely administered vaccine in the history of the world. Though BCG is inexpensive and effective, it loses its efficacy in young people and adults and is incapable of reducing the global incidence of TB. Also, the increase in the cases of multi drug-resistant TB (MDR-TB) highlights the need for a new effective vaccine.
At what stage is the vaccine?
VPM1002 has been undergoing clinical trials since 2008. It has proved its efficacy in animal and small scale human trials. According to the scientists, the vaccine when administered reduced the bacteria 100 fold in all animals. Phase I human clinical trials was already conducted in Germany (2009) and in south Africa (2012). Phase ‘2a’ trials conducted on infants in South Africa (2013) have confirmed safety and increased immunogenicity to fight against TB. The ‘Phase 2b’ trial has been started in South Africa and will be studying 416 babies (newborns) from HIV-positive and negative mothers. This phase of trial is expected to be completed by mid-2017.
Phase III trial in infants will begin in India once the phase ‘2b’ trial ends. Apart from this trial an independent phase III trial involving 2500 adult TB patients who have been infected and cured have been planned to be conducted in India. This independent trial aims to gauge the capacity of the vaccine to protect against the recurrence rate of TB in India. The trial in India is expected to last for 2 to 4 years.
What is the advantage of this vaccine over the existing one?
VPM1002 is expected to replace the current BCG vaccine to protect the children against TB. Unlike the present vaccine, it can also guard against the drug-sensitive and drug-resistant TB. Adults may also get benefitted from this vaccine. It will also be able to protect against pulmonary and extra-pulmonary TB in all age groups. In contrast, BCG vaccine can only protect against severe forms of the disease among children and is ineffective in preventing pulmonary TB in all age groups including children. VPM1002 is superior over BCG in terms of efficiency and safety.
What is situation of TB in India?
- TB is the top most infectious disease in India and has transformed into a major public health challenge. It is estimated that TB kills 2 people in every 3 minutes and roughly 750 every day. As of 2014, nearly 2.5 million people with active TB are living in India. Out of these cases, 70,000 cases are related to MDR-TB.
- TB recurrence (reinfection and relapse) rate is also higher with atleast 2 lakh to 2.5 lakh people who have been successfully treated getting infected again annually.
- WHO’s 20th edition of Global TB Report of 2015 has placed India at top among the 22 high burden countries.
- With increasing population, diagnosing and treating the patients before it gets transmitted to others is quite a challenge.
What are the steps taken by the government to eradicate TB in India?
TB was made as a notifiable disease in 2012. This means all the private doctors, caregivers and clinics has to report every case of TB they encounter to the government.
History of TB control
The first effort to control TB began in 1962 with the National TB Programme (NTP). In order to overcome the limitations in NTP, the government launched the Revised National TB Control Programme (RNTCP) in 1993. It adopted the internationally recommended Directly Observed Treatment Short-course (DOTS) strategy for TB control in India. RNTCP was able to effectively decentralized supervision of TB via the sub-district TB Units.
RNTCP II
RNTCP II was developed to address TB/HIV, MDR-TB and extend RNTCP to private sector. It was revamped with the lessons learnt while implementing RNTCP (1993-2005).
National Strategic Plan for Tuberculosis Control, 2012–2017
In order to fulfill the vision of a “TB-free India”, the government has launched National Strategic Plan for Tuberculosis Control, 2012–2017 with defined objectives:
- To ensure early and improved diagnosis of all TB patients including drug resistant and HIV-associated TB,
- To provide access to high-quality treatment for all diagnosed cases of TB,
- To scale-up access to effective treatment for drug-resistant TB,
- To decrease the morbidity and mortality of HIV-associated TB,
- To extend RNTCP services to patients diagnosed and treated in the private sector.
Nikshay
The RNTCP has come up with an innovative and visionary electronic recording and reporting system called Nikshay. It is a new web based system for effective monitoring TB patients across the country.
