Millions of Australian adults are unvaccinated and it's increasing disease risk for all of us

Public attention has recently focused on improving vaccination rates in Australian infants and children. But actually the largest unvaccinated group of people recommended for immunisation are adults.

Of 4.1 million unvaccinated Australians, 92% (3.8 million) are adults, and only a small fraction are children.

Improving adult vaccination rates will reduce their risk of illness and death, and lower transmission of infection in the community.

Fewer adults than children are vaccinated

The government provides free adult vaccines for influenza (flu), pneumococcal pneumonia and shingles for people over the aged of 65 years, and selected vaccines for those with underlying medical conditions, Indigenous people older than 15 years and pregnant women.

However, our latest research shows that only 51% of older Australian adults receive all government-funded vaccinations each year, compared to 93% of Australian children, and 73% of Australian adolescents. Coverage in eligible high-risk groups is even lower: around 40% of people with medical or occupational risk factors receive their annual influenza vaccine, and only 13% of indigenous young adults with medical risk factors receive their pneumococcal vaccine. Migrants, refugees and travellers are also often at risk and under-vaccinated.

Non-immunised children form a very small proportion of under-vaccinated Australians, yet public health efforts focus on coercive measures and financial penalties to improve immunisation rates in infants. Unvaccinated adults have been ignored.

Adults suffer from and spread diseases

Adults contribute substantially to ongoing epidemics of vaccine-preventable diseases. Most cases of whooping cough, for example, occur in adults. About half of all cases of measles that occur in Australia are in those aged 19 years or over.

In addition to poor adult vaccination rates contributing to the high cost of managing preventable infections, adults are often the starting point for epidemics because they have the highest rate of infections and so transmit infection more. Better vaccination rates in adults will reduce both cost and risk.

Health workers can be a vector for infection and trigger outbreaks among vulnerable patients. The highest risk institutions are hospitals, childcare centres and aged care facilities.

Health care and other institutions facilitate intense infection transmission and explosive outbreaks, where vulnerable patients, elderly residents or children may become ill and even die. The purpose of staff vaccination in these settings is not only individual protection, but protection of patients or children.

Staff have an ethical duty of care to reduce their own risk of infection and the risk they may pose to vulnerable others. Workers themselves may be at increasing risk, since hospitals and aged care facilities have an ageing workforce with associated underlying chronic health conditions.

The case for mandatory flu vaccination

Uptake rates of staff influenza vaccination continue to be low. Rates of vaccination in day care centre workers are less than 50%, and variably low in aged care workers and health workers.

When hospitals in the USA introduced mandatory influenza vaccination for health care staff, the response was variable, with legal challenges in New York.

There have been some great success stories lately from Melbourne, where hospitals have been able to get rates up to 80%. However, these hospitals have committed resources and personnel to implement intensive campaigns. Such vaccination campaigns based on voluntary or educational interventions will increase vaccination rates to 70-80%, but campaigns must be sustained and don’t achieve rates higher than this.

The groundwork for the introduction of mandatory influenza vaccination has been laid by many states and territories in Australia. For example, NSW introduced legislation in 2007 that required health care workers to demonstrate evidence of protection against a range of vaccine preventable diseases. The policy change was surprisingly well received and accepted by hospital staff.

Other states have similar recommendations for health care workers, but vary in the vaccines included and/or staff targeted. However, in all instances to date the influenza vaccine continues to be highly recommended but not required.

Mandatory vaccination still remains a controversial strategy that pits staff autonomy against patient safety. Coercive measures do work, but raise ethical issues. Further, some argue that the evidence of patient benefit for influenza is overstated.

Poor uptake of adult vaccination is due to many factors, including difficulty of access, lack of vaccination records, low perceived level of risk from vaccine-preventable diseases, lack of faith in vaccines for adults and value judgements about older people.

A range of strategies can improve vaccination rates, including a whole of life immunisation register, which helps doctors keep track of their patient’s vaccine history, eliminating financial barriers to vaccination, recording indigenous status and medical risk factors of patients, recommending vaccination to patients and providing reminders.

To improve immunisation in any occupational setting, it is important to commit resources, design health promotion programs, and provide culturally sensitive education on the risk of influenza and the overall benefits of vaccination.

It is also important to remove barriers and use regulation. For example, hospitals have patient infection outcomes linked to accreditation, but not staff vaccination. There are no such requirements for child care or aged care facilities. We could consider linking vaccination rates of staff to regulation of these institutions. We also need to ensure there are no other barriers to getting staff vaccinated.

C Raina MacIntyre receives funding from NHMRC, ARC, and has received in-kind or grant support for research from Pfizer, Merck, GSK and CSL/Sequirus.

Holly Seale has received funding from NHMRC and the ARC and has received funding from Sanofi Pasteur, GSK and CSL/Sequirus. She is affiliated with the Influenza Specialist Group.

Rob Menzies has served on an expert committee for, and received research funds from Seqirus.