TB Vaccination Reaching New Heights

By David Njagi
Freelance Journalist - Kenya

For the last 90 years, only 11 TB vaccine candidates have reached clinical testing globally.

On a windy Monday morning in Western Kenya, Theresia Anyango and her one-year baby Jeff Otieno calmly follows a counseling session taking place at the Siaya health center.

During the next year, Anyago and her son will be regular visitors at nurse Gregory Ouma’s desk.

He is in charge of counseling recruits of the phase two Tuberculosis (TB or MTB) vaccine trials at the Kenya Medical Research Institute/Centers for Disease Control and Prevention (KEMRI/CDC) site in Siaya, Kenya.

If all falls to plan, baby Otieno will be among 4,000 infants enrolled from five African countries who are likely to open a new chapter in the search for a new TB vaccine, 90 years after the Bacillus Calmette Guérin (BCG) vaccine was discovered.

It is a scientific stride that has however been shadowed with the onset of HIV and AIDS, a trend that researchers admit has sort of slowed the discovery of an advanced TB jab.

According to Dr. Videlis Nduba, the principal investigator at KEMRI/CDC in Kisumu, the renewed push to discover a superior TB vaccine was inspired by the fact that the current one, BCG, cannot be given to HIV infected infants.

“There is a high risk of BCG causing infection in infants living with HIV and so the World Health Organisation (WHO) does not recommend administering the vaccine to HIV positive babies,” Nduba explained to OnIslam.net.

It is easy to sympathize with Nduba’s drift. For the last 90 years, only 11 TB vaccine candidates have reached clinical testing globally. Most fail to show protection and so they are disqualified from progressing to the next trial phase.

This is not good news to medical science, where WHO has set 2050 as the target for eliminating TB, while the disease causes about two million deaths annually. However, there are possibilities, researchers say.

Equipped with new technologies and a trial that is proving to be effective by boosting the immune system to protect the body from being infected with TB, Kenyan researchers are hopeful that a breakthrough is in sight.

It spans a decade long stretch from 2000, when scientists at Kenya’s KEMRI/CDC trial sites began research on the vaccine candidate Aeras 402 Crucell Adenovirus 35.

According to Nduba, the vaccine is one of most promising candidates so far, because of its ability to stimulate the body’s immune system, hence mounting a potent response against TB.

“It expresses very strong cell wall antigens that interact widely with the immune system,” explains Nduba. “These three cell wall proteins have been identified as some of the most immunogenic in the cell wall of the TB bacteria.”

High Tech Vaccines

Although there is high optimism that the research can move to large scale experimenting with recruits, the world will have to wait for another two or three years to know the results. (Image: Mycobacterium tuberculosis which causes MTB).

Last year in September we started a phase II B proof-of-concept trials, he says.

Going by his description, in phase II studies researchers experiment with immunological markers, while in phase II B the search for early efficacy, or ability to prevent disease infection, begins.

But there is another landmark that is giving the search for an advanced TB jab a new edge.

From a paper fed research to Information and Communication Technology (ICT) powered field studies, the elusive search for a vaccine appears headed for new heights.

The establishment of a simple application system that uses wireless technology and Personal Digital Assistant (PDA) system in collecting and analyzing data at the research sites has simplified vaccine trials by about 90 per cent.

According to Dominic Mutahi, the Data Systems Manager at the Siaya Health Center, which is also a trial site, the technology is proving useful in saving time to collect and process data compared to days when researchers used paper.

That possibility is breathing a new lease of life into a remote village that is still to understand the power of ICT, and how it can help bridge the TB burden in the region, estimated at 80 per cent prevalence.

“The technology reduces transcription errors because if one enters an invalid value the system fires up,” says Mutahi. “Validation checks are what makes this the best attempt in TB vaccine research.”

By using a mobile phone PDA system, researchers are also able to track progress among vaccine trial recruits as well as receive feedback hence an easier way to track participants, schedule them and manage them, says Mutahi.

The silver lining shouldn’t, however, obscure the cloud.

Although there is high optimism that the research can move to large scale experimenting with recruits, the world will have to wait for another two or three years to know the results.

“The fact that there have been no danger signals to tell us that the vaccine is risky means the product can move forward with investigation,” says Nduba. “But until we have the efficacy trials results we cannot say that the vaccine works. It is after two or three years that we will be able to establish whether it works.”

Related Links:
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TB Treatment Cost to Rise as Drug Shortage Spread
Here’s a Youthful Way to Stop the Spread of TB
Curable TB Kills in Pakistan
Tuberculosis and AIDS: Oil to the Flame
David Njagi is a Nairobi-based freelance journalist whose work has been published in Africa and the United Kingdom. He is fluent in both English and Kiswahili languages. He can be reached at danjagi@gmail.com or +254 720 480 830.

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