three years running between 2015 and 2018. The last time that
happened was the Second World War. Despite some aspects of the
crisis being specific to the US, it isn’t the only area at risk; opioid use
has also been on the rise in places like the UK, Australia and
Canada.[74]
Unfortunately, it’s hard to track drug overdoses because it takes
especially long to certify deaths as drug-related. Preliminary
estimates for US overdose deaths in 2018 weren’t released until July
2019.[75] Although some local-level data is available sooner, it can
take a long time to build up a national picture of the crisis. ‘We’re
always looking backwards,’ said Rosalie Liccardo Pacula, a senior
economist at the RAND Corporation, which specialises in public
policy research. ‘We aren’t very good at being able to see what’s
happening immediately.’[76]
The US opioid crisis has received substantial attention in the
twenty-first century, but Hawre Jalal and colleagues at the University
of Pittsburgh suggest that the problem goes back much further. When
they looked at data between 1979 and 2016, they found that the
number of overdose deaths in the US grew exponentially during this
period, with the death rate doubling every ten years.[77] Even when
they looked at the state rather than national level, they found the
same growth pattern in many areas. The consistency of the growth
pattern was surprising given how much drug use has changed over
the decades. ‘This historical pattern of predictable growth for at least
38 years suggests that the current opioid epidemic may be a more
recent manifestation of an ongoing longer-term process,’ the
researchers noted. ‘This process may continue along this path for
several more years into the future.’ [78]
Yet drug overdose deaths only show part of the picture. They don’t
tell us about the events that led up to this point; a person’s initial
misuse of drugs may have started years earlier. This time lag
happens in most types of outbreak. When people come into contact
with an infection, there is usually a delay between being exposed and
observing the effects of that exposure. For example, during that 1976
Ebola outbreak in Yambuku, people who were exposed to the virus
often took a few days to become ill. For infections that were fatal,