Q&A: What COVID-19 means for TB vaccine development

The COVID-19 pandemic has led to unprecedented innovation and collaboration in vaccine development. In less than a year, 10 COVID-19 vaccine candidates have entered phase III clinical trials. But the coronavirus has also exposed significant gaps in funding and attention given to vaccine development for other infectious diseases, including tuberculosis.

To date, the century-old bacillus Calmette-Guérin vaccine, mainly used for infants and young children, is the only licensed TB vaccine. By 2021, it will be 100 years since the BCG vaccine was first administered in humans.

Several TB vaccines are in the advanced stages of clinical development. These include M72/AS01E, deemed by experts to be one of the most promising vaccine candidates against TB today.

But late-stage trials of TB vaccines are likely to take several more years, and it could take up to a decade before they can reach those who need them the most. Manufacturing the vaccines for trials, identifying geographical trial sites, building capacity in those areas to carry out the trials, and the studies themselves take years. TB vaccine development often requires at least three years of follow-up with trial participants to know whether a vaccine works.

Underfunding is also an issue, with a little over $100 million going to TB vaccine research and development annually.

Devex asked Dr. Dereck Tait, senior medical director for the IAVI and co-chair of the Stop TB Partnership’s working group on new TB vaccines, about challenges in TB vaccine development and how COVID-19 has impacted these efforts.

This conversation has been edited for length and clarity.

We’ve seen unprecedented acceleration in COVID-19 vaccine development, but why not for TB?

I think people sort of got complacent about tuberculosis, and so there was not a lot of research and development done into this. When we realized that, actually, TB vaccines needed to be developed, it did run into problems.

There are a lot of issues both with the pathogen and with the disease itself that we don't understand, which makes developing a vaccine for TB quite difficult. The other big issue we have is that we don't have correlates of protection at the moment. … We're not even sure what we are meant to be doing to the immune system to make someone immune to developing the [TB] disease.

We do not get the funding for TB vaccines that you do for coronavirus vaccines. For one coronavirus vaccine being developed, the amount of money being thrown at that is probably more than the entire research budget for TB vaccines — and this is one coronavirus vaccine out of more than 100 in development at the moment.

The other big difference between coronavirus and TB is [that] coronavirus is a viral disease, and sometimes [it's] easier to develop vaccines against viral diseases than bacterial diseases.

Could current investments in COVID-19 vaccines and their accelerated development benefit TB vaccine development?

One of the things that we're learning from coronavirus vaccines is that you can develop them incredibly quickly. There are an enormous number of lessons to be learned from it.

Obviously, one of the things that allows them to go really quickly is the fact that they get more ... funding. But they are also showing us ... ways where we could do things quicker. In TB vaccine development, often you take something from stage A to stage B, and then there's a gap while you work out what to do in stage C where you're waiting for approvals and that sort of thing. I think a lot of that so-called white space can disappear.

What are some of those lessons that can be learned from COVID-19 vaccine development?

I think some of the big ones are things like the very close collaboration between the developers, between funders, between regulators. That everyone's on the same page and moving forward at the same speed has been one of the big things that has been remarkable to me.

When someone comes up with an idea, the funding is available, [and] the regulators are willing to talk about the regulatory pathway that they feel you should be taking. They're more than willing to accept that this needs to be accelerated.

And I think also the fact that people have been able to jump onto platforms which haven't been used before. So for example, the RNA vaccines — and there are a few RNA vaccines out there for coronavirus — there's no registered RNA vaccine at the moment. But nevertheless, despite the fact that this is sort of a ... potentially novel vaccine once it's registered, that didn't slow anything down.

Governments feel the urgency to develop a COVID-19 vaccine because of the impact of COVID-19 on the economy. How do you think the TB community could make these different stakeholders feel that urgency toward a TB vaccine?

I think people have almost got used to [TB]. So there isn't that sense of urgency.

Tuberculosis is really a disease of poverty, of people that are disadvantaged, whereas coronavirus can affect any of us, from the president of the United States down to the very disadvantaged person. And I think that gave coronavirus a big impetus.

We know that [TB] doesn't get the sort of attention it should. … We and other people have been trying to change that for a long time through advocacy efforts, but it's quite difficult to get traction on that very often and again.

People will sometimes say to me, “What do you do?” and I said I work on TB vaccines. And the responses [were] very often along the lines of, “Is TB still a problem?” And this is in South Africa, where it is actually the leading cause of death. So there's an enormous amount of ignorance out there about TB. … Most people don't actually realize the massive problem that we face.

Source: Devex