Jeremy Laurance: Why I would never have a smallpox jab

Some people took David Blunkett at his word when he said that anyone who wanted a smallpox vaccination should ask their GP. A colleague told me that while she was waiting for a holiday vaccination at her local surgery last week, three people had turned up demanding smallpox jabs.

Are these people mad? First, GPs don't hold any smallpox vaccine, and are unlikely to get any. The BMA was not best pleased at the Home Secretary's daft assertion, and demanded a retraction. In the event of a terrorist attack involving the nasty bug, the task of vaccinating those at risk would fall to specially prepared teams of doctors, nurses and paramedics who have been appointed by the Government. They will seek to contain any outbreak by vaccinating contacts of a suspected case to create a ring of immunity around it – so called "ring vaccination".

That is the official strategy. But is it the right one? The Government has said that it will not be inviting the entire population of the British Isles to visit their GP to get a jab. It does not have enough vaccine, to start with. Even if it did, I would not be among those forming an orderly, or disorderly, queue. I have no intention of risking a jab for myself or for any member of my family against a disease that no longer exists.

Smallpox was wiped from the face of the earth in the late 1970s and has not, so far, returned. After the disease was declared eradicated in 1980, two stores of the virus were retained, one in the US and one in Russia, from which to create a new vaccine should the disease ever re-emerge. There has been speculation that some of the Russian stockpile may have fallen into terrorist hands following the break-up of the Soviet Union – but there is no hard evidence that this has occurred.

Let us suppose, however, that a terrorist group has acquired access to the virus. What then? In the first place, it is unlikely to be the biological weapon of first choice. Culturing the virus is difficult. As Professor John Oxford, the virologist, has put it: "If I were a mad scientist, I wouldn't choose smallpox as a terrorist weapon, I would choose anthrax. It is hardy and you can grow it in large quantities. Smallpox is difficult to grow and there are a lot of technical problems."

Even if these problems could be overcome, using it as a weapon would not be that easy. Smallpox is quite difficult to catch. It is spread through saliva droplets, so an infected terrorist walking down Oxford Street would need to cough over, sneeze at, kiss or otherwise have intimate contact with his or her victims. Evidence shows that smallpox is usually spread to household members, and is certainly much less infectious than, say, chickenpox or measles.

Even if you do catch it, all is not lost. It is true that there is no treatment and that all that medicine can offer is nursing care. But two-thirds of those who are struck by smallpox do recover.

Now, set this against the risks of the vaccine. Smallpox is one of the nastier jabs, with, according to the BMA, an incidence of severe reactions of one in 1,000 cases. Those at greatest risk are people whose immune systems are weakened as a result of cancer treatment or diseases such as HIV, and those who suffer from the skin condition eczema (the virus used in the vaccine can spread across the skin, infecting the arm and then the body).

In some cases, reactions can be fatal. A US study at the University of Michigan suggested that if 80 million people under the age of 30 were vaccinated, there would be 190 deaths. I would not fancy those odds myself until I could see the pustules on my would-be assassin's face.

So, the danger posed by the virus is not as desperate as it is sometimes painted. By far the greatest threat from a terrorist attack would be the creation of panic. How would people react in London if, say, there were an outbreak in Washington? How would they react in Birmingham if there were an outbreak in Manchester?

This may turn out to be the toughest challenge. The worst aspect of terrorism is, as we know, the terror.