The launch yesterday of a Vaccination Awareness Campaign by the Minister for Health and Children is an indication of the concern felt by doctors and other healthcare professionals at the falling levels of childhood vaccinations.
The "mini-epidemic" of measles in north Co Dublin during recent weeks came about as a direct result of falling immunisation rates. The low vaccination uptake is particularly a problem in the socio-economically deprived areas of the capital. While the Eastern Regional Health Authority reports an average 73 per cent uptake of the Measles, Mumps and Rubella (MMR) vaccine in the region, this figure masks much lower rates in the inner city and other areas throughout Dublin.
Communicable disease experts agree that a vaccination rate of 95 per cent is the minimum required to achieve successful infectious disease prevention. There is substantial evidence from the United States to suggest that in the case of measles, a significantly high rate of uptake will lead to the elimination of the disease.
The story of worldwide vaccination over the years has been a successful one. Smallpox has been eradicated. Whooping cough and TB have declined in response to concerted immunisation campaigns. The introduction of the Hib vaccine in the early 1990s has resulted in a huge drop in the number of cases of infant meningitis.
It is measles which has set the alarm bells ringing for health authorities and which has directly led to the launch of this awareness campaign. Prior to the introduction of the measles vaccine in 1983, there were about 10,000 cases per year in Ireland. This number has declined substantially; however, the recent outbreak is a timely reminder that the embers of infection can be fanned by a slackening in immunisation efforts.
The concept of "herd immunity" is important when considering the need for constant high rates of vaccination. It refers to a critical mass of natural infection, below which the population or "herd" retains a natural immunity from the disease. When vaccination levels fall below 95 per cent for a sustained period, this natural immunity is slowly eroded until an outbreak of infection takes place. Several outbreaks close together signal the onset of an epidemic, at which point the prevalence of the disease rises significantly.
Undoubtedly, the success of past immunisation programmes breeds a level of complacency among the public. "What you cannot see does not hurt you" seems to be a common belief - many parents have never seen a child with a serious infectious disease and consequently do not prioritise immunisation within their increasingly busy lives.
What issues should a vaccination awareness campaign target? Essentially, there are two categories: doctor issues and patient issues.
Doctors need to re-focus their efforts in "selling" immunisation as an integral part of preventative healthcare. To do this, they need ongoing education on the potential risks to children of infectious diseases. A major medical conference on the theme "Confronting the Vaccination Issue" will take place in the Royal Hospital Kilmainham tomorrow, and will be aimed at doctors, nurses and other healthcare professionals.
Doctors need practical encouragement also. Improved feedback and liaison between health boards and individual GPs on children who have defaulted will be an important step in improving the situation. The rapidly expanding computerisation of GPs' offices will aid communication and recall. Dedicated immunisation clinics as well as an opportunistic vaccination strategy are other important practical aspects.
Addressing parental concerns is probably the single largest obstacle standing in the way of increased immunisation rates. The MMR vaccine has been the target of sustained media attack. It has been incorrectly associated with an increase in childhood autism and Crohn's Disease. There has also been some controversy over alleged links with allergic disease such as asthma.
It is significant that MMR rates fall consistently below those of the Diptheria, Tetanus and Pertussis (DTP) vaccine. In some health board areas there is a 10 per cent difference in uptake rates between the DTP, which is administered in three doses between two and six months and the MMR, which is given as a single shot at 12-15 months. So, although the DTP requires three separate visits to the doctor, the completion rates are higher than the single-shot MMR. This points the finger at media scaremongering over the last couple of years as a cause for this discrepancy.
An increased interest in complementary medicine may be a lesser influence on parental choices in this area. Some homeopathic practitioners offer alternatives to conventional vaccinations.
Vaccine safety is a key issue for parents. They must be constantly reassured of the effective nature of vaccine licensing and surveillance by the Irish Medicines Board. Increased publicity concerning the adverse events reporting scheme, which covers all drugs including vaccines, might not go amiss.
It is in the health interest of the entire population that childhood vaccination resume its previous importance in the healthcare choices made by Irish parents.