Asian people in the street wearing protective masks

    A century ago the Spanish flu killed millions. A similar pandemic today could be even more deadly

    15 January 2018

    One hundred years ago the fate of the First World War hung in the balance. Germany, with four times as many troops as the Allies, was preparing its biggest ever offensive against France. Yet, within just a couple of months it had lost its advantage and was so severely weakened that it was forced to negotiate an armistice, ultimately ending the war. One key cause was an outbreak of Spanish flu within the German ranks, which spread rapidly, crippling both its divisions and supply lines. Those soldiers that escaped infection faced starvation.

    This is just one example of how the 1918 Spanish flu pandemic altered the course of history. And it wasn’t just troops affected, the virus was indiscriminate. One fifth of the entire human population was infected, including British Prime Minister, David Lloyd George, US President Wilson, the French Prime Minister and the German Chancellor. In less than a year it claimed the lives of about 50 million people, four times more than those lost to the war. Today, it is now accepted that it is just a matter of time before we see another flu pandemic that is as virulent as this, or worse. Yet one century on, despite advances in science and medicine, our best defence is nothing more than luck.

    In theory, we should be better prepared today than a hundred years ago. Modern surveillance will enable us to detect pandemics far quicker, while vaccine facilities across the globe that are currently churning out seasonal flu vaccines can be co-opted to protect people against whatever strain of the virus is causing the pandemic. And for those people who become infected we now have antiviral drugs, which, if the strain is sensitive, could go some way to help reduce the death rate.

    In practice, however, today the world is much smaller and more interconnected, with the potential for a pandemic to spread easier and quicker than ever before. Instead of travelling via horse and cart or by boat across a predominantly rural global population, today’s flu can travel at the speed of a jet plane between increasingly urban populations living in larger and more densely populated cities than ever before, all within a timeframe shorter than the incubation period of the virus.

    Medical advances do mean that we are now able to identify rogue strains quickly and create vaccines. But we are still relying on vaccine production technology that uses chicken eggs – which is somewhat ironic given that birds are one of the most likely sources of a pandemic flu virus. The problem with this is that it is not only slow, taking as long as five months to produce vaccines but also inefficient as often only a few doses can be made per egg. 

    At the moment, the time issue is tolerated because seasonal flu often hits the southern hemisphere first allowing time to develop a suitable vaccine before it travels north. However, with pandemic flu the virus has the potential to travel more quickly. Even when a flu vaccine is available it doesn’t always provide protection. Each year the World Health Organisation tries to anticipate which three or four strains are most likely to dominate flu season, which is always a gamble. But even when it gets it right, too often it is let down by the archaic vaccine production methods, as demonstrated with the current outbreak of ‘Aussie flu’. This particularly nasty strain of seasonal flu gripped Australia about four months ago and is now spreading across the north. Hundreds of millions of people have received the vaccine, but unfortunately it was only about 10 per cent effective against the dominant strain in Australia.  What this will mean for the efficacy of the vaccine in the Northern Hemisphere is not yet known.

    This is not uncommon. If you look back at the effectiveness of seasonal flu vaccines over the last twelve years, at best we’ve seen 60 per cent protection. Typically, it’s less than 50 per cent, sometimes much less. One reason for this is that when eggs are used mutations can occur during vaccine production, causing the wrong proteins to be produced which don’t stimulate the appropriate antibodies. With seasonal flu, depending on your luck, that may just determine whether or not you spend several days in bed feeling horrible. But with a more aggressive pandemic flu, that kind of ineffectiveness could translate into millions of deaths.

    What has been clear for a long time now is that we need a universal flu vaccine, one that provides effective and lasting protection against all forms of influenza. Yet with a thriving $3.3 billion seasonal flu vaccine market there is little incentive to invest in one. So, while there have been some promising developments, with trials of yet another candidate universal flu vaccine beginning last autumn, research into this field is woefully underfunded and a solution still a long way off.

    What this all boils down to is that the only thing preventing a devastating pandemic right now is luck. It’s luck that another virulent strain hasn’t yet spread. In 2009, we had a close call with swine flu, which still killed at least 300,000 people, but so far the most virulent strains have tended to be difficult to pass from human-to-human. It’s luck whether or not a flu jab will protect you. And when pandemic flu does hit, the speed at which it spans the globe could depend upon whether or not a stranger in a faraway land decides to board a plane or not – also luck.

    Despite the issues with current influenza vaccines, they are the best tool we have and are important to controlling flu. Vaccination still protects many people and even in those not fully protected it may reduce the severity, so everyone should get vaccinated.  But it is clear, we need a major effort to create better and ultimately universal flu vaccines.

    Sadly with infectious disease too often we wait until we see evidence of a global threat before we treat it like one. We saw this recently, first with Ebola and then Zika. Since then steps have been taken to reduce the threats to global health security caused by vaccine market failures. But with flu it’s the opposite problem, we need to find a way to overcome market entrenchment. Until we find a way to address this and start funding research in a way that is commensurate with the scale of the threat, then the only thing preventing a repeat of 1918 is a roll of the dice.

    Seth Berkley is the CEO of Gavi, the Vaccine Alliance