100 Years Later: A Single Vaccine for TB
By Lena Faust and Leigh Raithby
The last week of April marked World Immunization Week - a week to celebrate vaccines and the extraordinary progress that they have made possible in the fight against infectious diseases. Although it is important to reflect on the incredible global health accomplishments of vaccines, it should also be noted where urgent vaccine gaps remain, such as the lack of an effective vaccine for tuberculosis (TB) - an infectious disease that killed more people per year than any other prior to COVID-19. The Bacille Calmette-Guérin (BCG) vaccine, the only TB vaccine available today, turns 100 years old this year. But given the limited effectiveness of BCG, and the continued burden of TB in the world, the vaccine’s 100th anniversary is less a cause for celebration than an appalling testament to the neglect of diseases that predominantly affect the poor.
Developed in 1921, the BCG vaccine is effective only at preventing certain severe forms of TB in children and is ineffective at preventing the most common form of TB (pulmonary TB) in adults. But despite these serious limitations, it remains the only vaccine in use for TB to this day, 100 years after its introduction. This is a stark contrast to the 14 COVID-19 vaccines approved in just one year, exemplifying the continued neglect to address a disease that predominantly affects the poor.
In addition to the scientific challenges of developing a TB vaccine, another major barrier to TB vaccine development is financial. Investments in TB are lagging behind the commitment to a 2 billion USD annual target for funding TB research at the 2018 United Nations High-Level Meeting on TB. Unfortunately, these commitments are continuously going unmet, with less than half of the target amount actually being invested in TB research in 2019 (900 million USD), and only 3 countries (the Philippines, New Zealand and the UK) meeting their TB research funding targets. If there is to be any hope of an effective TB vaccine in the near future, countries must step up their investments in TB research and honour their commitments.
Amidst a global pandemic, it seems fitting that the theme of this year’s World Immunization Week is “bringing us closer.” Unfortunately however, as made evident by the deeply inequitable distribution of COVID-19 vaccines globally, we have also seen in the past year that vaccines can divide us, with wealthy countries allowing their interests to take priority over the call for global solidarity. Clearly, tuberculosis also exemplifies that rather than bringing us closer, vaccines have laid bare divides - most notably among socioeconomic fault lines. While COVID-19 has highlighted inequities in who gets access to available vaccines, TB is an example of inequity regarding for which diseases we bother to adequately invest in vaccine development at all.
Efforts to develop COVID-19 vaccines have demonstrated that scientific progress towards fighting an infectious disease can be made with remarkable speed if sufficient investment and political support are behind the efforts. When the COVID-19 pandemic ends, tuberculosis is likely to rise back to its rank of top infectious disease killer, and is likely to be even more devastating, given the disruptive impact COVID-19 has had on TB services globally. We need a new, effective TB vaccine, now. We know that the development of such a vaccine is possible - but it will require increased political will and global support.
Adapted from op-ed published in Health Affairs Blog