Sarah Neill (Public Health Officer Training Program, NSW Ministry of Health)Dr Grant Hill-Cawthorne (Clinical Advisor and Lecturer, Marie Bashir Institute for Infectious Diseases and Biosecurity and School of Public Health, University of Sydney)
Middle Eastern Respiratory Syndrome (MERS) is an emerging infectious disease of significant public health importance. The MERS coronavirus (MERS-CoV) is a new species in the Coronaviridae family, a family of viruses that also includes the causes of the common cold and Severe Acute Respiratory Syndrome (SARS).
MERS-CoV is most commonly occurring throughout the Middle East and Arabian Peninsula, where it was first identified in 2012. As an emerging virus, many of the epidemiological features are not yet fully understood which poses a great challenge and an opportunity to the public health and research community.
MERS-CoV is a zoonotic virus, which means that the virus originated in and was transmitted to humans by an animal source. As the human population expands, so does our interaction with animals and the natural environment, which has also resulted in an increase in emerging zoonotic diseases. Many viruses which have historically only been detected in animals are now being increasingly transmitted to humans. An infected animal may have no signs or symptom of illness, whereas the same virus may cause severe illness and death in infected humans.
The first outbreak of MERS-CoV infections occurred in April 2012 in Jordan . The index patient presented to a Jordan hospital suffering from severe acute respiratory illness, from which they later died. Healthcare workers treating the patient also came down with a similar illness. At the time the aetiology of this illness was not known, but was retrospectively identified as MERS-CoV after the virus emerged in Saudi Arabia and Qatar.
In September 2012, the World Health Organization (WHO) officially reported the emergence of a novel coronavirus (named MERS-CoV) and released the first case definition. This was followed by the implementation of active surveillance systems within healthcare services in the affected region.
As of 1 May 2015, the WHO had received notification of 1,111 laboratory confirmed cases of infection with MERS-CoV, including at least 422 related deaths (case fatality rate 38%). To date, over 80% of cases have occurred in the Kingdom of Saudi Arabia. Cases have also been detected in other Middle Eastern Countries, as well as Europe, Asia and the Americas. No cases have been detected in Australia. All cases of MERS have had a history of residence in, or travel to the Middle East, or contact with travellers returning from this area.
Figure 1 illustrates the details of the epidemic. Following initial identification, case numbers rose slowly until a significant increase was noted in April 2014. At this same time, clusters of disease were noted in healthcare facilities, suggesting that lax infection control measures in the healthcare setting were the most likely contributor for the rise. An audit of patient data in June 2014 revealed a significant number of deaths which had not previously been reported which were retrospectively added to case number reports. A surge of cases in February 2015 has been attributed to a rise in transmission in health care settings in Saudi Arabia.
Figure 1. Epidemic curve of 979 confirmed and 18 probable MERS CoV cases by confirmation status, as at 1 April 2015*
Text Alternative: As at 1 April 2015, there were 979 confirmed and 18 probable MERS CoV infections. Following initial identification of MERS CoV in March 2012, case numbers rose slowly until a significant increase was seen in April 2014. Case numbers then declined before a smaller peak followed in February 2015.
* Note: An additional 132 confirmed cases (84+48) are not included in the epicurve because individual onset dates are not available.
Four distinct epidemiological patterns associated with MERS cases have been identified:
Since September 2012, the WHO has periodically released updated case definitions as new information becomes available. The most recent case definition was released in July 2014:
A person with a laboratory confirmation of MERS-CoV infection, irrespective of signs and symptoms.
MERS is most commonly affecting older males, living or travelling in the Middle Eastern region. Most hospitalised cases have had chronic pre-existing co-morbidities, which indicates that those with weakened immune systems, older people and those with existing chronic conditions are more susceptible to contracting the virus or are more likely to be symptomatic.
Coughing, fever, shortness of breath and in some cases, muscle pain, vomiting and diarrhoea.
Rapid onset severe pneumonia/respiratory illness, organ failure (typically renal failure) and death.
The transmission routes and original source of the virus are not yet fully understood, and epidemiological research continues in this field.
Early research indicates that the virus most likely originated in the Egyptian Tomb Bat. However, dromedary camels are suspected to be the natural reservoir which is infecting humans. Human and camel genetic sequence data demonstrate a link between the virus found in camels and that found in humans. Primary cases which acquire infection after exposure to camels appear to develop more serious illness, so implementing infection control measures to limit primary transmission is a key priority in affected areas.
There have been no instances of sustained community transmission, which is likely contributing to the relative containment of the virus in the Middle Eastern region. However, clusters of human-to-human transmission have been reported mostly in the healthcare setting, and of the total case numbers, 20% have been healthcare workers . It appears that the virus does not transmit easily between people unless there is close physical contact, and for this reason, strict infection control measures are recommended, particularly when caring for patients with acute respiratory illness symptoms. The WHO has advised for the implementation of universal infection control measures, and transmission based precautions when in contact with suspected or confirmed cases.
There is currently no vaccine available for the prevention of infection and there is no anti-viral treatment available for those diagnosed with the virus. Until there is further evidence available, treatment remains mostly supportive and based on the patient’s own clinical condition.
Preventative measures are vital to prevent the initial transmission of the virus, particularly in affected regions. Recommendations include:
MERS is a notifiable disease in NSW. WHO have recommended for all member states to notify WHO and immediately undertake investigation of any new cases. Both NSW Health and the Australian Department of Health webpages are frequently updated as new information becomes available.
Dennis Meijer, Senior Policy Analyst and Sue Campbell-Lloyd AM, Manager, Immunisation Unit, Health Protection NSW
Data from the Australian Childhood Immunisation Register (ACIR) indicates that Aboriginal children have historically been vaccinated at lower rates, and experienced greater delays in vaccination, than non-Aboriginal children. As a result, Aboriginal children are at increased risk of morbidity and mortality associated with vaccine preventable diseases. The impacts of these gaps in vaccine uptake and timeliness are seen in notifiable diseases data where Aboriginal children have higher rates of vaccine preventable conditions such as Haemophilus influenzae type b, invasive meningococcal disease, whooping cough, invasive pneumococcal disease and rotavirus infection. NSW Health is implementing a number of strategies to improve immunisation coverage for Aboriginal children and here we provide a short overview of the NSW Aboriginal Immunisation Health Care Worker (AIHCW) Program.
AIHCWs were initially employed in 2010 in Local Health Districts (LHDs) to develop local strategies to improve the timely vaccination of Aboriginal children and reduce the coverage gap with non-Aboriginal children. The 3-year pilot program commenced in 2011/2012. Funding was allocated to LHDs based on estimates of their resident Aboriginal child population sourced from the Australian Bureau of Statistics (ABS).
To support implementation and evaluation of the program:
The primary focus of the program is on timeliness of vaccination for Aboriginal children in the first year of life. Vaccine coverage indicators were chosen to assess timeliness of the scheduled vaccine program milestones of 6 months of age (completion of the primary infant course), 12 months of age (measles and meningococcal vaccination) and 4 years of age (scheduled completion of the childhood schedule), and so were measured by the number of vaccinations reported to the ACIR within 3 months of those vaccine milestones being due.
A range of communication materials were developed to promote immunisation for Aboriginal people as part of the “Save the Date to Vaccinate” campaign. These materials were distributed throughout NSW to support LHD activities at local community events (see photos).
The employment of AIHCWs has enabled LHDs to undertake a range of targeted interventions to improve the timely vaccination of Aboriginal children. These include:
Data at the program milestones at 9 months of age (up to 3 months after the 6 month vaccines are due), 15 months of age (up to 3 months after the 12 month vaccines are due) and 51 months of age (up to 3 months after the 4 year old vaccines are due) indicate that vaccination coverage for Aboriginal children improved significantly between 2008 and 2013 as demonstrated in the graphs below. For vaccination coverage measured at 9 months of age, coverage for Aboriginal children had been fairly constant, and around 8% lower than for non-Aboriginal children between 2008 – 2012, whereas in 2013 with the AIHW program almost fully implemented the coverage gap narrowed to 4.4% (Figure 1), and exceeded 80% for the first time.
Figure 1: Percentage of Aboriginal and non-Aboriginal children fully vaccinated with vaccines due by 6 months of age by the time they are 9 months old, NSW, 2008 - 2013
Text alternative for Figure 1
For vaccination coverage measured at 15 months of age, between 2008 – 2012 less than 80% of Aboriginal children were reported as being fully immunised. In 2013 this increased to 82.5%.
Figure 2: Percentage of Aboriginal and non-Aboriginal children fully vaccinated with vaccines due by 12 months of age by the time they are 15 months old, NSW, 2008 – 2013
Text alternative for Figure 2
Figure 3: Percentage of Aboriginal and non-Aboriginal children fully vaccinated with vaccines due by 4 years of age by the time they are 51 months old, NSW, 2008 - 2013
Text alternative for Figure 3
For children at 51 months of age coverage in both Aboriginal and non-Aboriginal children has been increasing over time, due to a range of programs in place to improve uptake at this milestone. Figure 3 shows that the gap in coverage has narrowed from 12.7% in 2009 to 1.6% in 2013.
These promising trends are also seen at the routinely reported milestones of 12 months of age, 2 years and 5 years of age where the gap between Aboriginal and non-Aboriginal children has narrowed, and in fact at 2 years and 5 years of age in 2014 Aboriginal children had higher coverage than non-Aboriginal children.
As a result of the promising results, the program has been extended to help sustain these improvements. NCIRS will be conducting a formal evaluation of the program to document program activities and to describe internal and external stakeholder perceptions of program effectiveness to inform ongoing implementation.
Staff from Hunter New England LHD and the NSW Ministry of Health attend the Aboriginal Rugby League Knock Out in Raymond Terrace, October 2014 to promote immunisation for Aboriginal people
Staff from Illawarra Shoalhaven Local Health District attend a local community event to promote immunisation
Poster and brochure developed for Aboriginal parents as part of NSW Health’s “Save the Date to Vaccinate” campaign
The AIHCW Program has proven to be an effective public health intervention to improve vaccination coverage rates and timeliness for Aboriginal children. One challenge has been the recruitment and retention of staff during the program development phase and this should be facilitated by the decision to allocate recurrent funding to the program. It is also an opportunity to review the program to ensure that the KPIs, funding arrangements and reporting processes are appropriate going forward. Importantly, the program complements other NSW Health strategies, including the ‘Save the Date’ immunisation awareness campaign and the new child care legislative requirements.