When is a pandemic NOT a pandemic?

Every March 24th is World TB Day but there’s a good chance it will get even less of a mention than ever in the media this year, and this will be for an obvious reason – the coronavirus pandemic.

TB certainly escaped the media's radar this time last year. Here in the UK, for instance, on March 24th last year we’d just gone into our first lockdown so we were totally focused on that. What's more, just two weeks earlier (on March 11th) the WHO had officially declared the coronavirus to be a global pandemic so attentions everywhere were diverted well away from TB. (And on World TB Day itself last year, the first COVID case was reported from super-remote Easter Island, so a pandemic it most certainly was…).

But here’s a conundrum to consider on March 24th this year. Isn't TB also a pandemic? Given that it kills at least 1.5 million a year, it certainly sounds like it must be...

So what actually makes a pandemic a pandemic?

The WHO’s definition of a pandemic is helpfully simple – a pandemic is the worldwide spread of a new disease - so because of this definition (being that TB is an incredibly ancient disease) tuberculosis actually can’t be defined as a pandemic however infectious it may be and however many people it may rob of life. Shortly we’ll challenge this as a general conclusion, arguing that one part of it could and should be defined as one, but before that let’s just run a few numbers in respect of this disease so that we get a taste of the true scale of mortality that this infection generates.

First, try this one: in the 19th and 20th centuries (the rough total period of the global industrial revolution) it’s reckoned that TB probably caused the premature death of around a billion human beings.

Yes, you read that right – around a billion people are believed to have died from TB (or 5 million a year). Numerically, not even the Black Death got anywhere near close to this total (estimated at somewhere between 75 and 200 million) - although it should be added that with the total population of the world much smaller back in the middle ages and the short period of that pandemic the actual rate of death was certainly much higher than TB has ever been.

Estimates of deaths from TB since the foundation of the WHO, meanwhile, have been surprisingly variable and worryingly wayward, largely reflective of the neglect awarded it in this most recent period. Despite the WHO being originally founded by the UN in 1948 to primarily address three infectious diseases (one of which was TB), we can in fact find no remotely reliable estimates of annual global deaths for TB made by the organisation until the mid-90s. And even then, only some embarrassingly ropey estimates were made which were highly uncertain (maybe 2 million deaths a year, or maybe 3 million despite effective drugs having been developed…).

We’d say that, based on the estimates that are available, it’s not at all unreasonable to argue that probably 2.5 million were dying annually of TB each year during the 1990s right up until 2006 when it was first reckoned that the tide of death may have turned. This suggests that more than 35 million died of TB between 1990 and 2005 (and since then further reports suggest that sadly another 30 million have died as well). Who knows? And who actually even seems to care that much given the story of neglect so far? The only thing we can really say with any confidence is that nearly all of these deaths were occurring among the world’s poor.

But however immense these numbers may be, they still don’t make TB a pandemic.

Does it suffer because of this in terms of the funding awarded it? We'd say that it does. The total annual budget reluctantly awarded it by world leaders at the UN in 2018 (US$13 billion a year), for instance, is miniscule compared with the eye-watering amounts of cash recently lavished on the coronavirus pandemic since January 2020. What’s even more disconcerting is that even this comparatively diminutive TB budget wasn’t being near met at the end of 2019 (they only managed to cough up US$7 billion) even before we’d heard of the coronavirus or called it a pandemic.

So how, exactly, is TB defined epidemiologically?

Well, in 1993 the World Health Assembly officially called TB out to the world as a ‘Global Emergency’. This was the first (and we think only) time that any disease had been defined as such by the WHO. And no-one’s revised this declaration since in spite of the terribly slow progress containing it. So it's still a Global Emergency...

But since 1993, this Emergency situation hasn't just persisted, it's fundamentally altered by splitting in clinical terms into two distinct parts which we are in no doubt makes for two distinct diseases. This is the case simply because of the differential diagnostics required to confirm each one and the different drugs required to treat them. How else exactly is a disease clinically defined?

The main part of the Emergency can be called ‘old style’ in that, as it was in 1993, it is susceptible to the first line drugs that in most cases successfully treat it. Diagnosis is normally pretty straightforward too – comprising a sputum test analysed with a microscope and/or an X-ray (though in far too many cases diagnosis is still made on clinical judgement only).

Meanwhile the other newer part (which actually had already emerged into clinical significance in 1991, two years before that official declaration) is resistant to at least the two strongest of the four first line drugs – and because of this a completely different layer of diagnosis is needed to confirm it and a completely different set of drugs are required to treat it (with a much lower success rate to boot).

This 'new' disease is what is known as MDR-TB (Multi-Drug Resistant), and the biggest tragedy of all that its scale has been stoked exactly by the deficient attempts at controlling the Emergency. You only get resistance to the first line drugs if you don't manage those first line drugs properly.

So how many people might MDR-TB have killed so far? We’ve seen no half-decent official cumulative estimates of this in recent years (and just how different this is to the monitoring of COVID with the global total getting adjusted daily!). But back in 2010, the last cumulative estimate we can find, the WHO already reckoned that the death total was around 1.5 million. But let's compare this estimate to the one forecast for 2050 that was made in an official report on anti-microbial resistance that the UK government commissioned in 2015 - this reckoned that by 2050 the total lives prematurely lost to MDR-TB will have amounted to a frightening 75 million.

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MDR-TB – a new disease

So do these clinical distinctions make MDR-TB a distinct disease? It’s certainly hard to see how they don’t. (We're not on our own here: one expert quipped a few years ago that the only thing that these two diseases had in common were the two letters 'T' and 'B'). And given that this second clinically distinct disease has only recently emerged and has spread to every continent, this surely makes MDR-TB a global pandemic. It has to be a pandemic because it’s new and because it’s spread worldwide, but we notice that the WHO still only carefully refers to it as a ‘crisis’ in its annual reports.

Emergency or Pandemic… does it actually really matter what we call it anyway? Maybe not except in respect of comparing response to what we see in the media daily concerning the coronavirus pandemic.

What really matters is what’s being done about it

So for World TB Day 2021 this is what we ask.

We are approaching the 28th anniversary of the TB Global Emergency being declared. During this 28 year period the global authorities’ and world leaders' response has been collectively so deficient that probably at least 60 million lives have been lost to a disease that is in most cases curable. During this 28 year period a distinct secondary pandemic has not just been allowed to spawn from this neglect but self-evidently has also been casually ignored. We are at a true crisis moment when we know that all global public health efforts have switched to the immediate coronavirus pandemic, so can we at least ask you the global authorities and the leaders of our world not to forget the commitments you made in New York in 2018 - not least because they are so miniscule compared to what you are awarding COVID-19?

Defeating TB has certainly been made far harder because of the coronavirus, that’s for sure. But let’s not forget that those targets were majorly adrift BEFORE the coronavirus emerged – and it hardly bears thinking how far off they may be now.