The Communicable Disease Branch works closely with public heath units in the prevention, surveillance and control of preventable communicable diseases. Key activities include the promotion and provision of immunisation services, the surveillance of notifiable diseases, and the investigation and control of outbreaks.
Immunisation remains the backbone of communicable disease control. Most preschool immunisations (>85%), are provided by general practitioners and a small proportion are provided by community health and councils in NSW. Public health units and community health services provide high school based vaccination clinics. In 2013, NSW Health continued to facilitate high immunisation rates among children and adults through activities including:
Table 1. Proportion of Aboriginal children and all children fully immunised in NSW for three age groups, for the years 2012 and 2013
Source: Australian Childhood Immunisation Register
Note: from December 2013, the definition of fully immunised includes pneumococcal vaccine, which could account for a slight decrease in coverage at 12 months of age.
Table 2. Proportion of eligible students in Years 7 and 9 who received human papillomavirus (HPV), hepatitis B (Hep B), diphtheria-tetanus-pertussis (dTpa) and varicella (Vz) vaccine at school, NSW, 2012 and 2013.
Source: NSW School Immunisation Program
*HPV 2nd and 3rd dose data are preliminary as catch up vaccination will continue into 2014
**The large decrease in hepatitis B coverage between 2012 and 2013 was expected and reflects a cohort of children that previously received hepatitis B vaccination in infancy. 2013 was the final year of the school catch up program.
***Varicella vaccine is provided for students who do not have a history of chickenpox infection or vaccination.
NA: not applicable
In 2013 there were:
Long term trend in notifications are seen in the charts below.
Note: Surveillance for vaccine preventable diseases occurs through notification to public health units of patients with these infections by doctors, hospitals, laboratories and child care operators. This information allows public health units to initiate control measures and monitor the success of the vaccination program. There may be variation in the likelihood of notification of some vaccine preventable conditions. For example, the vast majority of patients diagnosed with invasive Haemophilus influenzae type b and meningococcal disease and measles are likely notified to public health unit, however, only patients with laboratory confirmed mumps and rubella and invasive pneumococcal disease require notification meaning that people diagnosed by clinical symptoms only will not be notified. Many pertussis infections are likely to be undiagnosed.
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Long term trend in notifications are seen in the chart below.
Note: Notifications of hepatitis B and hepatitis C provide only very limited information that can be used for assessing the epidemiological patterns of these infections. This is because many infections are asymptomatic, and so people who are infected may never be diagnosed, or only diagnosed many years after infection. Single positive tests do not reliably indicate the time of infection, and apart from the small number of people who have evidence of a previous recent negative test, it is difficult to identify acute infections. Variations in notifications may reflect changes in testing patterns rather than changes in the incidence of infection.
In 2013, NSW Health:
The HSP commenced on 9 May 2013 and by 31 December 2013 more than 100 doctors inexperienced in HIV had been supported. The program was well received with most doctors indicating they found the support valuable. The HSP is continuing to evolve as Local Health Districts share experiences on models of implementation and resources and tools are developed. A formal evaluation of the HSP will commence in 2014.
Note: sexually transmissible infections are often asymptomatic, and so people who are infected may never be diagnosed. Variations in notifications may reflect changes in testing patterns rather than changes in the incidence of infection.
In 2013, Health Protection NSW piloted a system to collect enhanced data on notifications of gonorrhoea to provide better information on the Aboriginal status and risk exposure of people diagnosed with gonorrhoea in NSW. Subject to the outcomes of the evaluation, new follow up procedures will be implemented.
Note: Surveillance of enteric infections depends on notifications of outbreaks by clinicians, or laboratory confirmation of specific organisms, which are likely to reflect only a small proportion of all enteric infections.
NSW Health continues to work closely with the NSW Food Authority to investigate reports of potential food borne infection.
In early 2013 a Salmonella Online Survey (SOS) was trialled to:
More than 300 people were invited to participate via a letter including a link to an online survey. A response rate of 22% was achieved. The survey responses frequently revealed foods or meals that were a likely source of the salmonellosis so advice could be given on safer alternatives, e.g. informing a case that smoothies containing raw egg are a particularly risky practice for salmonellosis. An evaluation found the SOS to be both a useful and acceptable form of public health follow up for salmonellosis cases and HPNSW aims to refine the methodology of the SOS and trial it again in 2014.
Although most enterovirus infections cause mild or no symptoms, they are also associated with a wide range of clinical diseases from hand-foot-and-mouth (HFM) disease to aseptic meningitis and acute flaccid paralysis. Transmission of enteroviruses, which includes the poliomyelitis virus, may occur directly via the faecal-oral route, contaminated environmental sources, or respiratory droplet transmission. Enterovirus infections (apart from poliomyelitis) are not notifiable in NSW.
In early March 2013, paediatricians from the Northern Beaches area of Sydney alerted the Northern Sydney Local Health District Public Health Unit to an increase in the number of young children presenting with severe neurological manifestations of enterovirus infection. The Sydney Children’s Hospital Randwick confirmed
human enterovirus 71 (EV71) in some of these cases and suspected infection in others.
Human enterovirus 71 (or EV71) is a major cause of HFM disease worldwide, and in the last 15 years has caused large outbreaks in South East Asia associated with severe neurological disease and deaths. Large outbreaks have been rare in Australia but have been reported from Victoria, Western Australia, and in Sydney in 2000-01.
NSW Health alerted clinicians and issued alerts to the community locally and statewide. The Sydney Children’s Hospital Network circulated advice to clinical staff on the diagnosis and management of patients with suspected neurological complications of enterovirus infection. Enhanced surveillance for current and recent cases of severe enterovirus infections in young children was implemented at both of Sydney’s Children’s Hospitals, and through the public hospital real-time emergency department surveillance system (PHREDSS) which demonstrated a gradual community spread of the infection to other parts of Sydney and outside Sydney. More than 100 suspected cases were identified, which were found to be due to either EV71 or one of a number of other enteroviruses. The outbreak peaked in March and had declined by June 2013. While the enhanced hospital case surveillance was stopped in June, emergency department surveillance through PHREDSS continued.
In November 2013 paediatricians at Children’s Hospital Westmead reported an increase in presentations of very young infants with fever, rash, and irritability. Testing showed that the infants were infected with
parechovirus genotype 3, which has been recognised as causing similar outbreaks amongst infants in Europe, North America and Asia, but had not previously been recognised in Australia. In collaboration with public health units and clinical staff in the three tertiary paediatric hospitals active surveillance was established and alerts were disseminated to paediatricians and emergency departments. Overall, in the period from October 2013 to February 2014, 183 cases were confirmed in infants, from all parts of the state. PHREDSS surveillance was found to be a sensitive tool to track the outbreak, and the indicator (admission of infants presenting with fever/unspecified) continues to be monitored.
Note: Notifications of laboratory legionnaires disease and tuberculosis are likely to approximate diagnoses, however only a tiny proportion of influenza cases are ever diagnosed and notified.
Note: Only laboratory confirmed diagnosed vector borne infections are notified in NSW. Many arbovirus infections are likely to remain undiagnosed.
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In 2013 there:
Note: Only laboratory confirmed diagnosed of zoonoses are notified in NSW, and mild cases may remain undiagnosed.