People with HIV will need to seek specialist medical advice before being vaccinated against smallpox in the event of a bio-terrorist attack, according to advice from the Department of Health.
Both the UK and US governments have said that they are preparing plans for mass vaccination programmes should there be terror attacks involving smallpox. Both governments have underlined that they are not expecting an attack, merely taking precautions.
In the unlikely event of an attack and public vaccination programmes being initiated, the UK Department of Health recommend that people who are pregnant or are immunosuppressed, or have excema, should seek advice from a doctor before receiving vaccination. For people with HIV this may entail disclosing their HIV status to healthcare workers who do not provide their regular HIV or general health care.
Smallpox is caused by the variola virus, and is highly infectious with an incubation period of between seven and seventeen days. Symptoms include headache, delirium, and vomiting before the “pox” or rash emerges. Approximately a third of people infected with smallpox die, and those who survive often have tell-tale disfiguring scars
Vaccination against smallpox was introduced in the eighteenth century and by the late twentieth century the disease had been eradicated from man, with only a few samples of the virus kept in secure laboratory conditions.
The vaccine used since the 1960s contains live virus closely related to the smallpox-causing variola virus, hence there are possible health concerns to people who are immunosuppressed, including those with HIV. In the US it has been estimated that if 80 million people aged under 30 were vaccinated against smallpox, about 200 people would die as a result. In addition, in common with most other vaccines, the smallpox vaccine does not offer 100% protection against the disease. What's more, concerns have been expressed that the type of vaccine stockpiled by the UK, which works against naturally occurring human smallpox, the Lister strain, may not be as effective against so called "battlefield" strains of the disease.
Government scientists have expressed confidence in the effectiveness of the Lister strain vaccine and have been eager to point out that they are not expecting an attack, but making sure they are prepared in the event of one.
Should vaccination be started it may be that for many people, including those with HIV, that the medical risks from the vaccine, and the disclosure of HIV status to non-specialist healthcare workers could outweigh the risk of contracting the disease.
To find out more about the use of vaccines and immunisations for people with HIV click here.