Research into vaccination rates shows older Australians are well protected against the flu but less so against pneumococcal disease, and whooping cough is a chink in the armour.
New figures released by the Australian Institute of Health and Welfare (AIHW) show three-quarters of Australians aged 65 years and older had a flu shot in 2009.
Just over half (55 per cent) were also vaccinated against pneumococcal disease.
Older Australians are at increased risk of serious complications or death if they contract these circulating diseases, and federal government programs offer them free vaccinations.
"The vaccination coverage for both seasonal influenza and pneumococcal disease in 2009 was similar to previous years," said Mark Cooper-Stanbury from the AIHW.
The report also showed just over 11 per cent of Australian adults received a whooping cough vaccination during the year, below the level that was expected.
"This is a concern given recent reports of increasing incidence of whooping cough in adults," Mr Cooper-Stanbury said.
"Somewhat encouraging is that uptake was substantially higher, at around 45 per cent, among healthcare providers and parents and carers of infants aged less than 12 months, but there is still scope for improvement."
The whooping cough vaccine is generally recommended for adults who have close contact with children and those planning to start a family.
The vaccine is one of the inoculations administered during childhood, and the study took in only people who had an additional jab as adults.
The AIHW report also looked at vaccinations for swine flu, and it confirmed the results of earlier research into the take-up of the matched a(H1N1) vaccine.
About 19 per cent of the adult population, or three million Australians, had received the swine flu vaccine by December 2009.
"Uptake for the H1N1 vaccine was higher among at-risk groups, particularly healthcare providers and childcare workers (26 per cent)," Mr Cooper-Stanbury said.
The AIHW surveyed more than 10,000 adult Australians to compile adult vaccination rates for 2009. The results will be officially released on Thursday.
It also found 96 per cent of people in the 65-plus target group who were vaccinated against seasonal flu and pneumococcal disease received their vaccinations free under federal government programs.