Destruction of smallpox vaccine

This week, the World Health Organisation will be making a decision about whether to destroy remaining stocks of smallpox vaccine.

As I'm sure you know, smallpox was eradicated more than 3 decades ago, thanks to the success of a global vaccination campaign. Given that smallpox used to kill so many people, its eradication is in my opinion perhaps the greatest achievement of medical science ever. Even those who don't rate it quite that highly would probably put it in their top 10.

But although natural smallpox transmission is no more, stocks of the virus still exist in 2 laboratories, one in the US and one in Russia. The question is whether those stocks should be destroyed.

The argument for keeping the stocks goes something like this. We cannot be sure that smallpox will not return. Maybe some stocks of the virus are held in another laboratory somewhere, perhaps by the "bad guys", intending to use it for bioterrorism. Or maybe bad guys intent on bioterrorism could create the virus in the lab, given that the DNA sequence of the virus is known and in the public domain. We therefore need to keep our stocks of the virus to help develop treatments for smallpox, namely improved vaccines and antiviral drugs.

There is some merit in that argument. If smallpox were to return, either via accidental release of the stocks or from bioterrorism, it would be helpful if we had more effective vaccines or specific antiviral treatments. There are clearly challenges in developing such treatments when there is no human smallpox in which to test them, so keeping live virus stocks improves the options for in-vitro testing of such treatments. However, we also have animal models of related viruses, such as monkeypox, which are useful in testing new treatments. And of course we are never really going to know for sure how successful a treatment is until we have tested it on humans with smallpox infection, which we cannot do anyway.

The argument for destroying the stocks is simply that by destroying the stocks, we make it less likely that smallpox can ever return. Murphy's Law (that if anything can go wrong, it will) seems to be very widely applicable, so keeping stocks of live and potentially infectious smallpox virus seems to be taking quite a risk. Sure, the virus is held in extremely high security facilities with incredibly strict procedures, but no security is ever foolproof. Let's not forget that the last ever person to die of smallpox infection contracted the disease after it had escaped from a laboratory.

In my opinion, we should destroy the stocks. It seems highly unlikely that stocks exist outside the designated laboratories and have got into the hands of bioterrorists. Surely they would have used it by now if they had? They must know that smallpox vaccines are currently being developed, and that stockpiles are being increased. The longer they wait, the less impact a deliberate release of smallpox would have.

Maybe one day, bioterrorists will be able to recreate the smallpox virus from scratch. The technology involved in doing so is complex, and is surely beyond the reach of any terrorist organisation at the moment. That may not always be true in the future, as improving technology makes sophisticated bioengineering more accessible to those in ordinary labs. However, surely the ability of the good guys to test smallpox vaccines using synthetic DNA fragments and the like should be able to keep up, and if we wait until terrorists have the ability to synthesise the virus, we will almost certainly have better treatments.

It is also worth noting, of course, that if smallpox does return following bioterrorist action, then we will have all the virus we want with which to test new treatments. And if it doesn't, then we don't need it anyway.

It seems to me that by far the biggest risk of smallpox returning is from some accident or security breach at the existing facilities. By destroying the stocks at those facilities, we eliminate that source of risk.

Why take the chance?