Many people are facing the question of whether to vaccinate themselves and their children against pandemic influenza H1N1 (so-called swine flu) – a vaccine that will provide safe and effective protection against a debilitating and potentially fatal illness. But the question comes at a time when some experts are concerned that a vociferous anti-vaccine lobby will undermine the mass vaccination campaigns being rolled out across Europe, putting the public and individuals' health at risk.
Vaccination – priming the body's immune system to resist attack – is the best defence an individual can have against infectious diseases. It can provide effective protection from infection, and means not having to face the uncertainty of whether treatment with anti-microbial drugs will be successful. Besides protecting us individually, vaccination also has a vital public health role because once the number of people immunised against an infection reaches a critical mass, that infection can no longer spread in the community.
Alongside improvements in sanitation, nutrition, and housing, vaccination has practically eliminated infectious diseases as a cause of childhood deaths in industrialised countries. Our children no longer die or are crippled by diphtheria, tetanus, whooping cough, or polio, to name a few examples. Even in the world's poorer countries that have yet to benefit from infrastructure improvements, vaccination has eradicated smallpox, is on the verge of doing the same for polio, and has cut deaths from measles by three quarters in the past decade alone. The countless millions of lives saved by vaccination are arguably science's greatest triumph.
The anti-vaccination movement took off in the 19th century as immunisation against smallpox was encouraged and, for example in the UK was then made compulsory by parliament in the 1840s and 1850s. As a 2002 article in the BMJ showed, arguments against the use of vaccines have barely changed in 150 years – opponents cite that they cause illness, they are ineffective, vaccination campaigns are an alliance for profit between government and industry, they are a poisonous chemical cocktail, immunity after vaccination is temporary, and a healthy lifestyle is an effective alternative. Yet in the past century and a half, anti-vaccines campaigners have produced no credible scientific evidence to support their arguments.
Concerns about the Pandemrix vaccine against H1N1, which is being widely distributed across Europe and in the UK, relate to whether it might itself cause flu, whether is has been adequately tested, and the safety of its component parts. The viral components in Pandemrix, which are necessary to stimulate immunity, are dead and cannot therefore cause an infection. The vaccine has been subjected to the same rigorous testing for safety and immunogenicity as seasonal flu vaccines, which have over the past 30 years had an unimpeachable safety record.
Clinical trials of Pandemrix among thousands of volunteers, including children as young as six months and the elderly, showed the vaccine produced a protective immune response in almost all those who received it, and raised no concerns about safety. The vaccine contains an adjuvant (designed to stimulate the immune response) based upon squalene; adjuvants of this type have been used in seasonal flu vaccines in Europe for more than 10 years without safety concerns. It also contains a preservative, thiomersal, which has had a controversial history, but whose safety is now backed by a mass of scientific data.
Although a milder illness than once feared, pandemic influenza is not a negligible disease. There have been an estimated 715,000 cases of H1N1 in the UK and 245 deaths. Children under five are particularly at risk of infection and serious illness, which is the reason why the vaccine is now being made available to this age group. About 80% of under-fives hospitalised for pandemic flu in the UK have no underlying health issues.
Reports from Wales of transmission from person to person of H1N1 virus resistant to the antiviral drug oseltamivir (Tamiflu) also raise concerns that treatment of pandemic flu may become difficult, and further emphasise the point that prevention is better than cure. Given that an effective vaccine without any known adverse event profile is available to prevent a disease with known potential for serious or even fatal illness, the decision to vaccinate seems an easy one to make.