Results, continued
Vaccine preventable diseases
Introduction
This section summarises the national notification surveillance data for laboratory-confirmed influenza and notifiable diseases targeted by the National Immunisation Program (NIP) in 2007. These include diphtheria, Haemophilus influenzae type b infection, measles, mumps, pertussis, invasive pneumococcal disease, poliomyelitis, rubella, tetanus and varicella (chickenpox, shingles and unspecified). Data on hepatitis B and invasive meningococcal disease, which are also targeted by the NIP, can be found in this report under 'Bloodborne diseases' and 'Other bacterial infections' respectively. Other vaccine preventable diseases (VPDs) presented in this report include hepatitis A under 'Gastrointestinal' and Q fever under 'Zoonoses'.
As of 1 July 2007, vaccines for human papilloma virus (HPV) and rotavirus were added to the funded NIP Schedule. In the lead up to this decision, the vaccines for HPV and rotavirus were registered by the Therapeutic Goods Administration and became available in the private market throughout Australia in 2006. In October 2006, the Northern Territory commenced a funded rotavirus immunisation program for infants born on or after 1 August 2006.
In 2007, the National HPV Vaccination Program was implemented for 12–13-year-old females, with a catch-up program for 13–26-year-old females. Currently there is no routine national surveillance system for monitoring HPV genotype infections in the general female population.
From 1 July 2007, all Australian children born on or after 1 May 2007 became eligible to receive a rotavirus vaccine. The rotavirus immunisation program aims to reduce the large social and economic burden of this disease in Australia where it is responsible for as many as 10,000 (50%) of all childhood hospital admissions for diarrhoea each year.38 Two rotavirus vaccines are currently licensed for use in Australia: Rotarix® (GlaxoSmithKline), a monovalent vaccine containing 1 strain of live attenuated human rotavirus which protects against non-G1 serotypes; and Rotateq® (CSL Biotherapies/Merck & Co Inc), a pentavalent vaccine containing rotavirus reassortants of human serotypes G1, G2, G3, G4, and P1. Both vaccines have been demonstrated in large-scale phase 3 trials worldwide to be safe and highly effective in the prevention of severe diarrhoea and hospitalisation due to rotavirus infections. Immunisation is recommended in the routine schedule as 2 doses at 2 and 4 months of age using the Rotarix® vaccine or 3 doses at 2, 4 and 6 months using the Rotateq® vaccine.13
Rotavirus is currently not on the National Notifiable Disease List.2 Although data were provided to the NNDSS by Western Australia and Queensland in 2007, it has not been analysed as part of this report. More details of rotavirus surveillance in Australia are provided in the Australian Rotavirus Surveillance Program annual report, 2007/2008.38
In 2007, there were 25,348 notifications of VPDs (17% of total notifications). This is 14% more than the 22,240 notifications of VPDs reported in 2006. Laboratory confirmed influenza was the most commonly notified VPD (10,403, 41% of all VPD notifications). The number of notifications and notification rates for VPDs in Australia are shown in Tables 5 and 6.
Diphtheria
There were no cases of diphtheria reported to NNDSS in 2007. The last case of diphtheria reported in Australia was a case of cutaneous diphtheria in 2001, which was the only case reported since 1992. Immunity to diphtheria measured in a national serosurvey in the late 1990s in Australia, showed high levels in people aged less than 30 years and declining immunity with increasing age.39 As there is now little opportunity to acquire natural immunity or to boost declining immunity with subclinical infection, it is therefore important for Australians to retain high levels of immunity through high vaccination coverage. This is particularly important to protect Australians against diphtheria when travelling in the 21 countries where the disease is still prevalent.40
Haemophilus influenzae type b disease
There were 17 notifications of Haemophilus influenzae type b (Hib) disease in 2007, a rate of 0.1 cases per 100,000 population. This was 5 less cases than reported in 2006. Eleven cases (65% of total) were in children aged less than 5 years and seven were infants aged less than 1 year. There were 8 cases in males and 9 cases in females, (male to female ratio 0.9:1), unlike 2006 when the ratio was 0.5:1 (Figure 31).
Figure 31: Notifications of Haemophilus influenzae type b infection, Australia, 2007, by age group and sex
Indigenous status was recorded for 16 of the 17 cases; seven were Indigenous and nine were non-Indigenous. The Hib notification rate was 1.4 cases per 100,000 in Indigenous people and 0.05 cases per 100,000 in non-Indigenous people—a ratio of 28:1. Between 2002 and 2006, Hib notification rates in Indigenous people have been between 6.2 and 18.8 times the rates in non-Indigenous people, except in 2002 when the Indigenous rate was 26 times that of the non-Indigenous rate (Figure 32).
Figure 32: Notification rate for Haemophilus influenzae type b infection, Australia, 2002 to 2007 by indigenous status
Cases under the age of 15 years were eligible for Hib vaccination in infancy. Of the 12 cases aged less than 15 years in 2007, five were unvaccinated, one partially vaccinated for age and three were fully vaccinated for age. Vaccination status for 3 cases was unknown or not supplied. One of the fully vaccinated cases aged 3 years had received 3 validated doses of vaccine and met the case definition for vaccine failure.
After nearly 20 years of Hib vaccination, Australia now has one of the lowest rates of Hib in the world.41 A recent study on the trends of invasive Hib in Australia between 1995 and 2005 concluded that almost 60% of invasive Hib cases in children are preventable.42
Influenza
The Australian 2007 influenza season was the highest season seen since influenza became nationally notifiable in 2001 (Figure 33). Notifications were 3.1 times the 5-year weekly rolling mean and peaked in August. As influenza only became nationally notifiable in 2001, a 5-year rolling mean cannot be calculated for years prior to 2006. There were 10,403 reports of laboratory-confirmed influenza in 2007, a rate of 49.5 cases per 100,000 population. Queensland notifications accounted for 44% of all influenza cases in Australia notified to NNDSS (Figure 34). Media coverage following the deaths of children due to influenza may have increased the rate of presentations for health care and testing for influenza in children and thus laboratory diagnosis and notification.43
Figure 33: Notifications of laboratory confirmed influenza, Australia, 2007, by week of diagnosis
Figure 34: Notifications of laboratory confirmed influenza, Australia, 2007, by state or territory and week of diagnosis
The highest notification rates occurred in the Australian Capital Territory with 115 cases per 100,000 population, followed by Queensland (110 cases per 100,000 population), the Northern Territory (85 cases per 100,000 population) and Tasmania (84 cases per 100,000 population) (Table 6).
There were 2,240 notifications in children aged less than 5 years (22% of all notifications). As in previous years, influenza notification rates were markedly higher in children under 5 years (notification rate of 168 cases per 100,000 population) compared with older age groups (43 cases per 100,000 population) (Figure 35). The rate was highest in those under 1 year of age (271 cases per 100,000 population). The overall male to female ratio was 1:1.03.
Figure 35: Notification rate for laboratory-confirmed influenza, Australia, 2007, by age group and sex
In 2007, 9,901 (95%) influenza notifications in NNDSS had viral type data. Of cases including type data, 90% (8,942) were influenza A, 9% (914) were influenza B and 0.5% (45) were mixed infections. A breakdown of influenza notification by virus type and jurisdiction is shown in Table 17.
Table 17: Notification of laboratory confirmed influenza, Australia, 2007, by state or territory and type
Influenza type |
State or territory | Aust | |||||||
|---|---|---|---|---|---|---|---|---|---|
| ACT | NSW | NT | Qld | SA | Tas | Vic | WA | ||
| Influenza A | 346 |
1,487 |
179 |
4,384 |
262 |
388 |
1,266 |
630 |
8,942 |
| Influenza B | 44 |
180 |
3 |
200 |
18 |
27 |
309 |
133 |
914 |
| Influenza A&B | 0 |
43 |
0 |
0 |
0 |
0 |
2 |
0 |
45 |
| Influenza type unknown | 0 |
208 |
1 |
6 |
0 |
0 |
12 |
275 |
502 |
| Total | 390 |
1,918 |
183 |
4,590 |
280 |
415 |
1,589 |
1,038 |
10,403 |
Of 1,406 influenza virus isolates analysed at the WHO Collaborating Centre for Reference and Research on Influenza (WHOCC) in 2007, 826 (58.7%) were A(H3N2) strains, 483 (34.4%) were A(H1N1) strains and 97 (6.9%) were influenza B. The WHOCC reported that early testing showed a difference in the proportion of H1 and H3 strains across jurisdictions. Western Australian and Victorian isolates were mainly type A(H3) while Queensland and New South Wales isolates were a mixture of type A(H1) and A(H3).43
Antigenic analysis of the Australian 2007 strains showed a genetic drift away from the 2007 vaccine strains for both A(H1) and A(H3).
Circulating strains were:
- A(H1): A/New Caledonia/20/99-like and drift strain A/Solomon Islands/3/2006-like;
- A(H3): A/Wisconsin/67/2005-like and newly emergent variant A/Brisbane/10/2007-like; and
- B: B/Malaysia/2506/2004-like (21% – Victoria lineage) and B/Florida/7/2004-like (79% – Yamagata lineage).
- The 2007 vaccine included:
- A//New Caledonia/20/99(H1N1) – like strain.
- A/Wisconsin/67/2005(H3N2) – like strain.
- B/Malaysia/2506/2004 – like strain.
Invasive pneumococcal disease
There were 1,474 notifications of invasive pneumococcal disease (IPD) in Australia in 2007, a rate of 7.0 cases per 100,000 population. This was a small increase from the 1,445 cases reported in 2006 (7.0 cases per 100,000 population). An increase in notification rate between 2006 and 2007 was seen in the Australian Capital Territory (34 cases, 10.0 cases per 100,000 population), the Northern Territory (66 cases, 30.7 cases per 100,000 population) and Queensland (322 cases, 7.7 cases per 100,000 population). The lowest notification rate in 2007 was seen in Victoria (278 cases, 5.3 cases per 100,000 population).
In 2007, males accounted for 827 of the 1,474 notified cases of IPD. In all age groups there were more male than female cases, resulting in a male to female ratio of 1.3:1. Figure 36 shows that the highest rates of IPD in 2007 were among the elderly aged 85 years or over (34.3 cases per 100,000 population) and in children aged 1 year (33.4 cases per 100,000 population).
Figure 36: Notification rate for invasive pneumococcal disease, Australia, 2007, by age group and sex
Additional data were collected on cases of invasive pneumococcal disease in all Australian jurisdictions during 2007. Details can be found in the invasive pneumococcal disease annual report published in the next edition of CDI.
Measles
There were 12 cases of measles notified to NNDSS in 2007 representing a rate of 0.1 cases per 100,000 population. This was a significant reduction compared with the 125 cases notified in 2006 (0.6 cases per 100,000 population) associated with a large multi-state outbreak (Figure 37). Figure 38 shows that since national surveillance began in 1991, the measles annual rate for Australia has only been lower in 2005 (0.05 cases per 100,000 population).
Figure 37: Measles notifications, Australia, 2002 to 2007, by month of diagnosis
Figure 38: Trends in measles notification rates, Australia, 2002 to 2007, by age group
In 2007, notifications were reported from New South Wales (4), Queensland (4), Victoria (2), South Australia (1), and Western Australia (1).
In 2007, there was a substantial decrease in the notification rate in all age groups compared with 2006 (Figure 38). There was 1 case in an 11 month-old infant, three in children aged between one and 4 years, one in the 5–14 years age group, four in the 15–24 years age group and three in the 25–34 years age group. Of the 12 cases, five (42%) were not vaccinated, one (8%) was partially vaccinated for age and the vaccination status for the remaining 6 cases (50%) was either unknown, missing or coded as not applicable. Overseas acquired measles infection accounted for seven (58%) of the 12 cases in 2007, four of which were not vaccinated, 1 case was partially vaccinated and in 2 cases the vaccination status was either unknown or not stated. The NIP recommends that children are vaccinated for measles with the combined measles, mumps, rubella vaccine (MMR), at 12 months and 4 years of age.13 Data on serogroup type was available for 2 cases and was identified as D4 and D5 respectively. The majority of the measles cases in 2007 (8; 67%) were male.
Mumps
In 2007, there were 579 notifications of mumps (2.8 cases per 100,000 population), a twofold increase on the 275 notifications of mumps (1.2 cases per 100,000 population), reported in 2006 and a ratio of 3.8 compared with the 5-year mean. Cases were reported from all jurisdictions, with the majority (323) from New South Wales but also including large numbers from Western Australia (106 cases), the Northern Territory (58 cases) and Queensland (46 cases). However, the highest mumps notification rate was in the Northern Territory with 27 cases per 100,000 population, followed by Western Australia and New South Wales, each with 5 cases per 100,000 population.
Indigenous status was recorded for 396 of the 579 cases and of these, 126 (32%) were reported as Indigenous and 270 as non-Indigenous. The relatively large proportion of the total number of mumps cases in 2007 identified as Indigenous was a significant increase from the absence of Indigenous cases in 2006 and the 5-year mean of 1.2 Indigenous cases.
Of the Western Australian and Northern Territory cases in 2007, 75% (80 cases) and 78% (45 cases) respectively were identified as Indigenous and were associated with outbreaks in the Kimberley region of Western Australia and Indigenous communities in the Northern Territory (Map 6).
Map 6: Notification rates for mumps, Australia, 2007, by Statistical Division of residence and Statistical Subdivision for the Northern Territory
A clinical audit of immunisation status in a remote Indigenous community in the Northern Territory affected by the mumps outbreak identified low vaccination coverage rates in those over 20 years of age. More than 50% of mumps cases in the 10–49 year age range showed no record of vaccination (although this is based on case notes and may not have been complete for individual patients).44 Ten of the cases reported in the Northern Territory occurred in students at a boarding school. Public health investigation at the time noted that these cases likely received an early dose of the MMR vaccine at 9–10 months of age, which was consistent with historical recommendations in the Northern Territory and now no longer apply.45 The current NIP Schedule recommends 2 doses of MMR given at 12 months and 4 years of age, unless there is a contraindication. The efficacy following immunisation at less than 12 months of age may be reduced compared with those immunised at 12 months of age due to circulating maternal antibodies. The Australian Immunisation Handbook recommends that when MMR is given under 12 months of age, this dose should be repeated at 12 months of age or 4 weeks after the first dose, whichever is later.13
The Kimberley outbreak, in which genotype J was identified, began in early July and peaked by the end of 2007. This outbreak had epidemiological links to cases in the Northern Territory (personal communication, Gary Dowse, Communicable Disease Control, Directorate, Western Australia Department of Health).
The number of mumps notifications in Australia has been increasing since 2004 (Figure 39). This increase in mumps notifications has meant that the rates in Australia in 2005, 2006 and 2007 (Figure 40) have exceeded the 1 case per 100,000 population threshold for disease elimination and are indicative of endemic mumps transmission in Australia.41
Figure 39: Notifications of mumps, Australia, 2002 to 2007, by month of diagnosis
Figure 40: Notification rate for mumps, Australia, 2007, by age group
In 2007, there were cases of mumps in all age groups with the highest notification rates in the 25–29 years age group (11.4 cases per 100,000 population) while rates in young children aged less than 5 years remained low (0.8 per 100,000 population, or 11 cases) (Figure 41). In 2007, the majority of cases (325; 56%) were male.
Figure 41: Trends in notification rates for mumps, Australia, 2002 to 2007, by age group
Trends in notification rates by age group for mumps (Figure 40) show a sharp increase in the rates for the 25–34 and 15–24 years age groups, and a small decline in the less than 1 year age group compared with 2006.
Information on vaccination status was available for 330 cases (57%) of which the majority (60% or 197 cases) were not vaccinated, 7% (24 cases) were partially vaccinated for age and 33% (109 cases) were fully vaccinated for age. The high rate of mumps in the 25–34 years age group represents a susceptible cohort of individuals who may not have been immunised. In fact, 57% of those who were not vaccinated were in this age group. Of those with known vaccination status, males were 1.5 times less likely to be vaccinated than females. Mumps vaccine was made available in Australia in 1980 for use at 12–15 months of age and was combined with measles vaccine in 1982. Therefore, no childhood doses of mumps vaccine were available to most individuals in the 25–34 years age group (birth years 1973–1982). This cohort was also not targeted in the Measles Control Campaign in 1998 where the 2nd dose of MMR was offered to primary school aged children (5–12 years).
Pertussis
Pertussis is the most common vaccine preventable illness in Australia, with periodic epidemics occurring at intervals of three to 5 years on a background of endemic circulation. Rates are normally higher in late winter and spring, however from 2004 onward, non-seasonal activity remained elevated compared with previous years (Figure 42).
Figure 42: Notifications of pertussis, Australia, 2002 to 2007 by month of diagnosis
In 2007, 5,323 cases of pertussis were notified to NNDSS representing a rate of 25.3 cases per 100,000 population. This was lower compared with that reported in 2006 (10,996 cases; 53.1 cases per 100,000 population). The decrease in rate of pertussis notifications in Australia from 2006 to 2007 may be in part due to errors in diagnosis using serology identified in 2006. In October 2006, PanBio Ltd announced a major revision in the cut-off level for their pertussis serology tests. The original kits were withdrawn from the market towards the end of 2006 and a revised version released in October 2006. A decrease in notifications was observed in the last months of 2006.
Notification rates in 2007 increased with age, with the highest notification rate in the 65–69 years age group (45.9 cases per 100,000 population; Figure 43). There were more cases among females (3,079; 57.8%) than males (2,232; 42.0%), with 12 cases not having sex specified. The highest rates among females were in the 60–64 years age group (48.4 per 100,000 population) and the highest rates in males were in the 65–69 years age group (45.8 per 100,000 population). There were no recorded deaths for pertussis in 2007.
Figure 43: Notification rate for pertussis, Australia, 2007, by age and sex
Trends in the pertussis notification rate in different age groups are shown in Figure 44. In 2007, pertussis notification rates declined in all age groups compared with 2006 with the exception of the 1–4 and the 5–9 years age groups, both of which experienced a small increase. In particular, the decline seen in the 10–19 years age group following the introduction, of adolescent (15–17 years olds) vaccination to the NIP in January 2004, continued in 2007. In 2007, 82% of pertussis cases were aged 20 years or over, compared with 50% in 2000.
Figure 44: Trends in the notification rates of pertussis, Australia, 2002 to 2007, by age group
Notification rates for pertussis varied considerably by residential location (Map 7).
Map 7: Notification rates for pertussis, Australia, 2007, by Statistical Division of residence and Statistical Subdivision for the Northern Territory
The highest rates were reported from the Darwin region of the Northern Territory, central northern New South Wales, parts of Victoria and the southern areas of South Australia, with rates in these locations being higher than the national rate. By jurisdiction, the highest rates were in Queensland (36.7 cases per 100,000 population) and New South Wales (30.0 cases per 100,000 population).
Poliomyelitis
In 2007, Australia had its first case of acute flaccid paralysis (AFP) due to wild poliovirus in 30 years. Although a major clinical presentation of the poliovirus infection, AFP occurs in less than 1% of poliovirus infections. The imported case of polio occurred in a 22-year-old male student arriving from Pakistan in July 2007. The poliovirus was detected by the National Poliovirus Reference Laboratory (NPRL) for Australia, which along with the Australian Paediatric Surveillance Unit (APSU), co-ordinates surveillance for AFP. This imported case highlights the importance of continued high quality AFP surveillance in Australia and the maintenance of high levels of polio vaccine coverage despite our current polio-free status.
The WHO target for AFP surveillance in a polio non-endemic country is 1 case of AFP per 100,000 children aged less than 15 years. In Australia in 2007, a total of 27 eligible AFP cases were notified to the NPRL via the APSU between 1 January and 31 December, of which 26 had sufficient information for classification. The 2007 non-polio AFP rate, based on the 26 cases as classified by the Polio Expert Committee (PEC), was 0.65 per 100,000 children aged less than 15 years and hence below the performance indicator set by the WHO. Details of the 2007 notifications, including the imported case, are provided in the 2007 annual report of the Australian NPRL.46
Since the removal of oral polio vaccine from the immunisation schedule and its replacement with inactivated polio vaccine in November 2005, poliovirus should no longer be isolated from clinical specimens in Australia without overseas travel.
The imported polio case in 2007 highlighted the need for a comprehensive, coordinated and consistent response to such events with any poliovirus isolated in Australia fully investigated to determine the source of the virus and to prevent any local transmission. As a certified polio-free country, Australia is required by the WHO to have an action plan for responding rapidly to importations of wild poliovirus. The Acute Flaccid Paralysis and Poliomyelitis Outbreak Response Plan for Australia (Polio Response Plan) was initiated in late 2006 by the Department of Health and Ageing in consultation with CDNA and PEC, and refined following the experience gained during the control of the imported case in July 2007. This plan, based on a risk management approach to biological emergencies, is designed as a high level national response outlining potential scenarios for occurrence of a case of poliovirus infection in Australia, the importance of surveillance and notification procedures and to guide key stakeholders involved in detection, investigation and containment of a potential poliovirus infection in Australia. The Polio Response Plan was endorsed by Australian Health Protection Committee at their meeting in December 2008 and satisfies the WHO requirement that all member states have an action plan for rapid response to outbreaks of poliovirus.
Renewed efforts in 2007 to eradicate polio worldwide saw an overall global decrease of 35% in case numbers between 2006 and 2007, including a significant 81% decrease in the number of wild poliovirus type 1 (WPV1) cases during this time. However, the risk of importation of WPV remains, with 1,304 confirmed cases reported globally to the WHO, the majority (92%) of which occurred in the 4 polio endemic countries of Nigeria, India, Pakistan and Afghanistan where the transmission of wild poliovirus continues.47
Rubella
In 2007, there were 36 notifications of rubella (0.2 cases per 100,000 population), a decrease compared with the 59 notifications in 2006. Cases were reported from Queensland (14), New South Wales (8), Victoria (7), Western Australia (4), the Australian Capital Territory (2) and South Australia (1).
Small case numbers were reported across the age groups between 0 and 69, except for the 5–9 years age group where no cases were reported. The majority (61%) occurred in cases aged between 20 and 39 years, with the next highest (14%) occurring in cases aged between 0 and 4.9 years (Figure 45). The mean age was 27.7 years.
Figure 45: Notification rate for rubella, Australia, 2007, by age group and sex
The overall male to female ratio of notified cases in 2007 was 0.8:1, with 16 males and 20 females. This contrasts with 2006 and some previous years (1999, 2002 and 2003) when there was an overall predominance of males notified.
Information on vaccination status was available for 16 of the 36 cases of which six were fully vaccinated for age, three were partially vaccinated and the majority (7) were not vaccinated. Vaccination status in the remaining 20 cases was either unknown or missing.
In Australia, populations at risk of rubella include young males who did not receive the rubella immunisation in school based programs,48 migrant women who did not receive rubella vaccines in their countries of birth,49,50 and Indigenous women with inadequate immunity.51 In 2007, of the 7 male cases where information on vaccination status was reported, five were not vaccinated (3 of which were between 20 and 30 years of age and 2 between 0 and 4 years of age) and two were partially vaccinated. Of the 9 female cases in 2007 with vaccination status reported, seven were fully or partially vaccinated and two were not vaccinated (both of which were between 25 and 44 years of age). None of the rubella cases in 2007 was identified as Indigenous.
Figure 46 shows trends in rubella notification rates in different age groups, with a slight increase in rates in the 1–4 years age group in 2007 compared with 2006, but otherwise continuing at the low levels seen since 2003.
Figure 46: Trends in notification rates of rubella, Australia, 2002 to 2007, by age group
There were 2 cases of congenital rubella reported in 2007, one of which was fatal. The cases were reported from New South Wales and Victoria. While this is an increase compared with 2006 when there were no cases reported, and compared with the 5-year mean of 1.4 cases, it is consistent with notifications in earlier years including 2002 (2 cases), 2003 (3 cases), 2004 and 2005 (1 case each year). Altogether there were 16 cases of rubella notified in women of child bearing age (15–49 years) representing 80% of the total number of female cases in 2007.
Brotherton et al (2007)41 suggest that the achievement and confirmation of the elimination of locally acquired rubella circulation may require targeted immunisation of migrants from countries with low levels of rubella vaccination and the establishment of rubella genotyping in Australia.
Tetanus
In 2007, there were 3 notifications of tetanus. One case occurred in an unimmunised 93-year-old male from Tasmania and resulted in his death. The other 2 cases were a male aged 76 years of unknown vaccination status and an unimmunised female aged 79 years.
Varicella infections
In November 2005, the varicella vaccine was added to the NIP Schedule as a single dose due at 18 months (for children born on or after 1 May 2004), or as a catch-up dose at 10–13 years of age. In 2006, CDNA agreed to make varicella infections notifiable in Australian jurisdictions. Three categories of varicella infection are notifiable: chickenpox, shingles and varicella infection (unspecified).
By the end of 2007, 6 jurisdictions were sending data to NNDSS, with NSW having decided in 2006 not to make varicella infections notifiable. The legal processes to make varicella notifiable in Victoria were still underway.
In 2007, there were 7,496 varicella notifications from the 6 notifying jurisdictions, with 1,651 (22%) reported as chickenpox, 1,547 (21%) as shingles and 4,298 (57%) as unspecified varicella infection.
Varicella zoster infection (chickenpox)
In 2007, there were 1,651 notifications of chickenpox reported from 6 jurisdictions, a rate of 18.5 cases per 100,000 population. The highest rates were reported from the Northern Territory (91.7 cases per 100,000 population; 197 cases) and South Australia (46.2 cases per 100,000 population; 732 cases).
A total of 1,145 cases (69.4 %) occurred in children aged less than 10 years. The highest rates were in the 0–4 years age group (107.5 cases per 100,000 population; 613 cases) and within this age group children aged 4 years had the highest notification rate (175.9 cases per 100,000 population; 196 cases; Figure 47).
Figure 47: Notification rate for chickenpox, Australia,* 2007, by age group and sex
* Excluding New South Wales and Victoria.
Of all notifications, there were slightly more male than female cases notified, with 881 males (53.4%) compared with 768 females (46.5%). Two cases did not have the sex specified.
Indigenous status was recorded for 85% of notifications, with the majority (1,224; 74.1%) being reported as non-Indigenous. A total of 172 notifications (10.4%) were Indigenous, with 255 (15.5%) being reported as not stated or blank.
Ninety-two cases (5.6%) were recorded as fully vaccinated for age; three partially; and 458 unvaccinated. There was no vaccination status information on the remainder of the notified cases (1,098), and no recorded deaths from chickenpox in 2007.
Varicella zoster infection (shingles)
There were 1,547 notifications of shingles reported to NNDSS in 2007 from 6 jurisdictions, a rate of 17.3 cases per 100,000 population. The highest rates were in the Northern Territory (41.4 cases per 100,000 population, 89 cases) and South Australia (37.1 cases per 100,000 population, 587 cases).
There were more female cases (852; 55.1%) than males (695; 44.9%). The highest rates were in the over 85 years age group (50.6 cases per 100,000 population; 69 cases; Figure 48). There was 1 recorded death for cases of shingles.
Figure 48: Notification rate for shingles, Australia,* 2007, by age group and sex
* Excluding New South Wales and Victoria.
Indigenous status was recorded for 80.8% of notifications, with the majority (1,186; 76.7%) being reported as non-Indigenous. A total of 64 (4.1%) notifications were Indigenous, with 297 (19.2%) being reported as not stated or blank.
Varicella zoster infection (unspecified)
There were 4,298 cases of varicella infections (unspecified) based on laboratory diagnosis from 6 jurisdictions in 2007, a rate of 48.2 cases per 100,000 population. The highest rates were reported from Queensland (73.5 cases per 100,000 population; 3,072 cases), Western Australia (31.3 cases per 100,000 population; 659 cases) and the Australian Capital Territory (30.3 cases per 100,000 population; 102 cases).
There were more notifications in females (2,333; 54.3%) than males (1,957; 45.5%), with 2 deaths occurring due to unspecified varicella zoster infection. The age distribution of unspecified varicella infections is shown in Figure 49.
Figure 49: Notification rate for varicella zoster infection (unspecified), Australia,* 2007, by age group and sex
* Excluding New South Wales and Victoria.
Indigenous status was recorded for 27.0% of notifications, with the majority (1,099; 25.6%) being reported as non-Indigenous. A total of 65 notifications (1.5%) were Indigenous, with 3,134 (73.0%) being reported as not stated or blank.
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Communicable Diseases Surveillance
This issue - Vol 33 No 2, June 2009
NNDSS Annual report 2007
Communicable Diseases Intelligence