Vaccine Preventable Disease (VPD) surveillance studies and reports
These projects involve diseases for which vaccines are available.
A review entitled Vaccine Preventable Diseases and Vaccination Coverage in Australia, 1993-1998 [report] was published. This contained details of sickness and deaths from VPDs during the 8 years between 1993 and 1998. Information has been gathered from the 3 national sources (notifications of diseases, admissions to hospital and deaths). Diseases include diphtheria, Haemophilus influenzae type b (Hib) disease, measles, mumps, pertussis, poliomyelitis, rubella, tetanus, hepatitis A and B, invasive pneumococcal disease and varicella. Changes in the immunisation schedule between 1993 and 1998 are also documented, and details of immunisation coverage (obtained from the Australian Childhood Immunisation Register) are also included.
A further review entitled Vaccine Preventable Diseases and Vaccination Coverage in Australia, 1999-2000 has been published as a 'Communicable Diseases Intelligence' supplement. It concentrates on notification and hospitalisation data for VPDs for 1999 and 2000, but includes comparative data from 1993 onwards. It is available here.
Measles
A strategy to monitor the occurrence of measles was designed in collaboration
with the Communicable Diseases Network of Australia and New Zealand (CDNANZ)
and the Public Health Laboratory Network (PHLN).
Reference 36.
In the national Measles Control Campaign, carried out in 1998, 96% of the 1.78 million schoolchildren were vaccinated against measles. After the Campaign 94% of children aged 5-12 years were immune to measles, compared with 84% before the Campaign. Most parents were satisfied with the school campaign. Levels of protection also rose after the Campaign in preschoolers (82% to 89% protected).
A full report of the evaluation is available here as an html or pdf file, and a published version is available in the Bulletin of the World Health Organization 2001 Volume 79, No.9 (September): 882-888. Reference 80 . Since the Campaign, Australia has experienced a very low incidence of measles, with most cases in adults, so a booster injection of MMR (measles-mumps-rubella vaccine) is now being offered to young adults.
Hepatitis A
Occurrences and deaths from hepatitis A between 1952 and 1977 have been studied. Notifications declined from a peak of 123 per 100 000 in 1961 to 3 per 100 000 in 1989. The 1990s saw low baseline disease rates, with peaks in 1991, 1996 and 1997. Reference 38. Hospitalisation and serosurvey data are being used to "model" this disease, in consultation with the United Kingdom's Communicable Disease Surveillance Centre.
Hepatitis B
Hepatitis B infection in families of recent immigrants has been studied. Both horizontal and vertical spread of infection in families was documented using molecular epidemiology techniques. One child had vaccine escape mutant infection. This study was carried out in collaboration with the Department of Infectious Diseases at the University of Sydney. Reference 12.
Varicella (chicken pox)
As part of an international study using molecular epidemiology, it was found that the strain of varicella-zoster virus circulating in Australia is similar to the one in the USA, but dissimilar to the Japanese strain and to the vaccine strain. Reference 25.
A serological study of antibodies to varicella-zoster virus in Darwin showed a much higher prevalence than is usually found in tropical areas. Reference 78.
Chickenpox during pregnancy or in the first month of life can cause serious problems in infants. Congenital and neonatal varicella in Australia was studied as one of the research projects of the Australian Paediatric Surveillance Unit . A small but constant occurrence was demonstrated over the 3 years of this study, providing background information against which to assess the effect of varicella vaccine, licensed in Australia in 2000. Reference 55.
Rubella
After the Measles Control Campaign a serosurvey was carried out. This showed that immunity to rubella in 1-18 year olds had risen from 83% to 91%. The Campaign had rectified a serious gap in rubella immunity in children aged 10-12 years, who had received on MM (measles-mumps) vaccine in infancy, and had not reached the age for the MMR (measles-mumps-rubella) vaccine scheduled (at that time) for children in grades 6 and 7.
The Campaign did not help those aged 19-49. In this group 97% of females but only 85% of males were protected, reflecting the previous vaccination program for teenage girls. This group is being targeted in the current catch-up program.
The occurrence of rubella and congenital rubella has been studied since 1993, using data from the National Notifiable Diseases Surveillance System (NNDSS) and the Australian Paediatric Surveillance System (APSU). Despite widespread vaccination rubella has continued in the community, particularly in men and boys. Between 1993 and 2001 inclusive, 21 infants born in Australia with the congenital rubella syndrome were reported (5 in each of the years 1993-1996, one in 1997, and none in 1998, 1999, 2000 or 2001). Reference 40.
Respiratory syncytial virus (RSV)
A preliminary epidemiological study of RSV infection in NSW documented the age distribution, seasonality and morbidity, using data from LabVISE, the NSW Inpatient Statistics Collection and the Australian Bureau of Statistics Cause of Death Register. Reference 60.
Recent trends and future preventive strategies for diphtheria were also studied. Reference 70.