Delivering a Healthy WA
Disease WAtch

March 2012, Volume 16, Issue 1

Full issue

Ongoing pertussis epidemic in Western Australia

Western Australia is in the midst of a pertussis (whooping cough) epidemic that commenced in mid-2011.  It follows the period from 2005–2010, in which WA had the lowest pertussis notification rates in Australia.

During the same period, other states and territories experienced relatively sustained epidemic activity, in contrast to the generally recognised pattern of 3–4 yearly epidemics. Hence, with its last epidemic year in 2004, WA has been well overdue for a pertussis epidemic, as was recognised in a previous Disease WAtch article. 1

Figure 1 shows that both nationally—and to a lesser extent in WA—there has been a stepwise increase in pertussis notification rates over the past few years, despite high vaccine coverage in young children. This suggests a re-setting of baseline levels of activity in the community, with relatively more disease observed in older children and adults. Similar patterns have been observed in other developed countries. The reasons for this are thought to include waning vaccine-induced immunity; better awareness of the disease; increased testing, including greater availability of more sensitive PCR diagnostic tests; improved reporting and surveillance; and changes in the organism itself. It is also thought that acellular pertussis vaccine, introduced in Australia in 1999, may not confer as long-lasting immunity as that provided by the whole cell vaccines used previously.

Figure 1 – Pertussis notification rates for Western Australia and Australia, 1991–2011

Line graph showing a large rise in number of notifications in WA and Australia, in the last few years.

There was a record 4015 pertussis notifications in Western Australia during 2011, almost double the number recorded in the 2004 epidemic year. The latest epidemic began noticeably in July 2011.  From then notifications increased steeply to a monthly peak of 766 cases in November 2011, as shown in Figure 2. Notifications stabilised around this high level through to January 2012, with hopeful signs of a decline in February (data for February were incomplete at the time of writing).

Figure 2 – Number of pertussis notifications in WA by month, January 2010–February 2012*

Column graph showing that the rise in pertussis numbers has been particularly acute between July 2011 to Jan 2012.

*Note: Data for February 2012 were incomplete at the time of writing

Figure 3 shows the number of cases and notification rate by age for all cases of pertussis notified in WA in 2011. The highest notification rates were in children of primary school age, with the lowest rates in teenagers and young adults, probably reflecting the benefits of the Year 7 booster dose of pertussis vaccine. Notification rates then increased again in older adults, being highest in those aged 35–44 years. Within the primary school age range, risk increased stepwise from age 5 through to age 11 years, indicating progressive waning of protection following the pre-school booster dose of pertussis vaccine, generally given at age 4 years.

Pertussis in school-aged children and adults poses a risk to infants who live in the same households, and who are most vulnerable to the complications of pertussis. Hospitalisation rates for pertussis are highest in children under 1 year of age, especially those younger than 6 months who have not completed their primary course of pertussis vaccination. In recent years, around 50% of children under 1 year of age who have been diagnosed with pertussis have been hospitalised—amounting to 56 cases in 2011. The rate of hospitalisation declines to almost nil in children aged 2 years and above. One death from pertussis was reported in each of 2008, 2009, 2010 and 2011 in WA; all were children aged 2 months or younger. 

Figure 3 – Number and rate of pertussis notifications in WA by age group, 2011

Column graph showing the highest notification rates were in children of primary school age, with the lowest rates in teenagers and young adults, probably reflecting the benefits of the Year 7 booster dose of pertussis vaccine.

Conclusion

Despite relatively high vaccination coverage, pertussis notification rates have increased both nationally and in WA in recent years. An epidemic of pertussis commenced around July 2011 in WA, and is ongoing, with the number and rate of notifications far exceeding levels recorded previously.  Whilst notification rates are currently highest in primary school aged children, attributed to waning of vaccine-induced immunity, the impact of the disease remains greatest in infants under 1 year of age, with about 50% of these cases requiring hospitalisation.

Vaccination remains the most effective intervention to reduce the burden of pertussis, notwithstanding the fact that it provides imperfect protection. In addition to the routine childhood schedule, as a consequence of increasing rates in older age groups, the Australian National Health and Medical Research Council recommends that a booster dose of diphtheria-tetanus-pertussis vaccine (dTpa)  be offered to the following adult groups2:

  • parents planning a pregnancy, or both parents as soon as possible after delivery of an infant
  • other household members and carers, including grandparents
  • those working with young children, such as child-care workers
  • health care workers
  • any adult expressing an interest in receiving a diphtheria-tetanus booster.

Adult pertussis vaccines must be provided by private prescription, although the WA Department of Health is funding the vaccine for parents, grand-parents and other household carers of babies less than 6 months of age in order to protect newborns during the current epidemic. This program will be reviewed at the end of June 2012.

As indicated in the box below, the clinical and public health management of pertussis is directed toward early identification and treatment of cases; exclusion of infectious individuals from settings where they may transmit disease, in particular to vulnerable infants; and targeted vaccination and antibiotic prophylaxis for exposed infants and household, healthcare and childcare contacts who may expose vulnerable infants.3,4

Summary of clinical and public health management for cases of pertussis

(For further details, see: Pertussis information for GPs and other healthcare providers3 and/or National guidelines for the public health management of pertussis.4

Case management

  1. Verify diagnosis: PCR on a nasopharyngeal (aspirate or swab) specimen preferred in cases presenting within 21 days of onset. Dry nose or throat swabs are acceptable. Serum IgA testing (acute and convalescent) is an option, particularly for late presenting cases.
  2. Antibiotic treatment: Commence prior to result if reasonable suspicion that patient has pertussis, and if less than 21 days since onset of cough. Clarithromycin, azithromycin, erythromycin or trimethoprim/sulfamethoxazole are recommended. For dosage see Therapeutic guidelines: antibiotic.5
  3. Exclusion: From work, school, childcare and other settings with young children for 21 days following cough onset or until 5 days of treatment has been completed.
  4. Notify: Communicable Disease Control Directorate (Perth metropolitan area) or your rural Public Health Unit of confirmed cases. Public Health Units will assist with contact management if appropriate.

Contact management:

  1. Ensure that other children in a household or childcare setting are up-to-date with recommended pertussis vaccines.
  2. Antibiotic prophylaxis is recommended only for high-risk contacts or in high-risk settings, including: households and child-care settings with young children who have not had 3 doses of pertussis vaccine; women in their last month of pregnancy; and infants, staff and parents in maternity wards and neonatal nurseries. Prophylaxis is not recommended in settings such as primary schools, high schools, tertiary education facilities or work-places.
  3. Exclusion: Only for child contacts who attend childcare or pre-school and who have received less than 3 doses of pertussis vaccine, for 14 days after last exposure to the case, or until they have completed 5 days of an appropriate antibiotic.

References

1. Communicable Disease Control Directorate. Disease update: pertussis in Western Australia. Disease WAtch. 2010; 14: 2-5

2. National Health and Medical Research Council. Australian immunisation handbook, 9th ed. Canberra: Australian Government Department of Health and Ageing, 2008.

3. Communicable Disease Control Directorate. Pertussis—information for GPs and other healthcare providers on clinical and public health management. March 2010.

4. Department of Health, WA. National guidelines for the public health management of pertussis. OD 0129/08, 2008.

5. Antibiotic Expert Group. Therapeutic guidelines: antibiotic. Version 14. Melbourne: Therapeutic Guidelines Limited, 2010.

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Influenza Update

With the influenza season fast approaching, it is time to consider who needs to be protected against influenza.

The composition of influenza vaccines for Australia this year is the same as last year, with the components being:

  • A (H1N1): an A/California/7/2009 (H1N1) - like strain
  • A (H3N2): an A/Perth/16/2009 (H3N2) - like strain
  • B: a B/Brisbane/60/2008 - like strain

It is important to impress on patients the need to get the vaccine every year, because virus strains change frequently and immunological evidence indicates that immunity following vaccination does not provide long-term protection.

Recommended groups for immunisation

Under the National Immunisation Program (external site) (NIP) influenza vaccination is provided free for:

The WA paediatric influenza vaccination program

The WA Paediatric Influenza Vaccination Program will continue in 2012.

Children from 6 months up to their fifth birthday (not already eligible to receive influenza vaccine under the NIP) are eligible for State-procured influenza vaccine. The Communicable Disease Control Directorate strongly encourages providers to discuss the benefits and risks of influenza vaccination with parents of young children.

Please note that in 2012 Fluvax is not approved by the TGA for use in children under the age of 5 years and should only be used in children aged 5 to 9 years based on a careful consideration of the potential benefits and risks in the individual child. See further safety information (external site).

Vaccination for pregnant women

This year, greater emphasis is being given to protecting pregnant women against influenza. The Royal Australian and New Zealand College of Obstetricians and Gynecologists and the National Health and Medical Research Council has recommended that all women be offered influenza vaccination during pregnancy.

Experience with prior annual seasonal influenza epidemics and the pandemic in 2009 has clearly demonstrated that pregnant women are at increased risk of morbidity and mortality from influenza.

It is important that pregnant women are vaccinated against influenza because:

  • influenza vaccination of pregnant women reduces maternal hospitalisations.
  • influenza vaccination of pregnant women reduces illness in the newborn.  Pregnant women who are vaccinated against influenza make antibodies which cross the placenta and help protect the baby for the first 6 months of life (when they are too young to receive the vaccine themselves).

Vaccinating new mothers reduces the risk of influenza virus transmission from her to the newborn after delivery.

The influenza vaccine is safe for pregnant women. The influenza vaccine is an inactivated vaccine so does not cross the placenta.  There is no evidence of congenital defects or adverse effects on the foetus of women who are vaccinated against influenza in pregnancy.

Influenza vaccine can be given in any trimester of pregnancy. 

The 2012 influenza campaign will be launched in late March and will be similar to last year’s campaign including the “Fluey” logo.

Communications material will be provided by the Department of Health and Ageing through a direct mail out to health professionals including general and specialist practitioners, key primary and tertiary care organisations and other immunisation providers. 

Pneumococcal (23vPPV) Vaccine Update

The Therapeutic Goods Administration (TGA) has completed a review on the increase in adverse events notification following revaccination with pneumovax 23vPPV.  The Australian Technical Advisory Group on Immunisation (ATAGI) has also reviewed the role of 23vPPV within the National Immunisation Program (NIP).

The TGA has determined that the adverse events were not due to a batch-related problem. It found the increased number of reports were likely due to known high rates of injection site reactions after a repeat dose of 23vPPV, increased rates of revaccination following the introduction of free 23vPPV through the NIP in 2005 and an increase in reporting following publicity of the batch recall.

ATAGI has concluded that the benefits of a first dose of 23vPPV outweigh the risks of severe adverse reactions. For second doses, the greatest benefit in comparison to risk appears to be for older adults with a higher risk of invasive pneumococcal disease (IPD), who are revaccinated with 23vPPV more than 5 years after their first dose.

The findings of both of these reviews have led to new recommendations relating to the revaccination of adults with 23vPPV.  These are, that:

  • adults aged 65 years and over are at higher risk of contracting pneumococcal disease than the rest of the population, with the majority of deaths from this disease occurring in this age group.
  • a dose of 23vPPV should be given to adults at 65 years of age. Every effort should be made to provide a dose to anyone over 65 years old who has not previously received a dose of 23vPPV.
  • a repeat dose (a single revaccination) of 23vPPV is no longer routinely recommended for this population group.

A repeat dose of 23vPPV is recommended only for those adults aged 65 years and over who have a condition that predisposes them to a higher risk of IPD than other adults in this cohort. This repeat dose is to be given 5 years or more after the first dose to smokers and those with the following predisposing conditions:

  • asplenia, either functional (including sickle-cell disease) or anatomical
  • conditions associated with increased risk of IPD due to impaired immunity
  • chronic illness associated with increased risk of IPD
  • CSF leak.

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Where to go for the right public health advice

The Department of Health provides a wide range of public health services so it is important to know where to go for the right advice.

Local public health staff, working at 9 Public Health Units throughout the state,  can assist you from 8.30am to 5pm, Monday to Friday, with issues relating to:

  • disease notification
  • contact tracing for specific diseases
  • the public health management of specific infectious diseases such as pertussis, meningococcal disease and hepatitis A
  • immunisation, including:
    • vaccines used for different age cohorts
    • ordering of vaccines
    • cold chain breaches
    • authority to order Rabies vaccine and immunoglobulin
    • authorisation for non-standard vaccines such as IPOL and hepatitis B
  • vaccines for high-risk groups such as hepatitis B contacts
  • education and staff training.

Contact details for local Public Health Units

Public Health Unit Telephone Fax

North Metropolitan (Perth)

9380 7700

9380 7719

South Metropolitan (Perth)

9431 0200

9431 0223

Great Southern (Albany)

9842 7500

9842 2643

Southwest (Bunbury)

9781 2350

9781 2382

Kimberley (Broome)

9194 1630

9194 1633

Midwest (Geraldton)

9956 1985

9956 1991

Goldfields (Kalgoorlie)

9080 8200

9080 8201

Wheatbelt (Northam)

9622 4320

9622 4342

Pilbara (Port Hedland)

9158 9222

9158 9253

For advice on catch-up immunisation, contact the Central Immunisation Clinic by telephoning 9321 1312 between 8.30am and 4.30 pm, Monday to Friday.

For advice on issues relating to refugee health or tuberculosis contact the Anita Clayton Centre /Humanitarian Entrant Health Service on 9222 8500.

For urgent notifications and public health advice on communicable disease issues after hours (5pm to 8.30am) telephone the Department of Health duty officer on 9328 0553.

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Year 7 school-based immunisation program

The Western Australian school-based vaccination program provides Year 7 students with free vaccinations against hepatitis B, diphtheria, tetanus, pertussis, varicella-zoster and human papilloma virus.

Vaccinations are administered in metropolitan schools by the Department of Health’s Child and Adolescent Community Health Services and some local government authorities, and in regional and remote schools by regional population health units. Since 1 July 2011, GPs in Western Australia have been able to order vaccines used in the Year 7 school immunisation program, without prior approval from the Communicable Disease Control Directorate, for vaccinating children who may have missed vaccine doses in school.

Data from the Year 7 program have been entered into a Statewide, web-based database since 2009. Below is a summary of the vaccine coverage in 2011 and some frequently asked questions regarding the program for GPs.

In 2011, more than 27,000 Western Australian Year 7 students received at least 1 vaccine as part of the program and 87.5%, 77.4%, 67.4% and 29.7% completed their adolescent vaccination(s) against dTpa, HPV (females only), HBV and VZV respectively. Uptake of all doses is depicted below.

Column graph showing the percentage of uptake of vaccines for free vaccinations against hepatitis B, diphtheria, tetanus, pertussis, varicella-zoster and human papilloma virus amongst year 7 students.

The apparent low uptake of HBV and VZV vaccines is due to the fact that many children do not require vaccination against these infections in Year 7 because they had already been vaccinated as an infant or have natural immunity to the disease.

Frequently asked questions for general practice

What is the Year 7 immunisation program?

The Year 7 immunisation program is a Commonwealth-funded school-based program which requires all states and territories to deliver the vaccine in schools. Vaccines used in the delivery of this program must be reported back to the Commonwealth. We are aware that students miss their vaccination for a variety of reasons and given that these vaccines are important in protecting the student, we now make them available to GPs for Year 7 catch up.

Where can children access the Year 7 vaccinations?

The Year 7 immunisation program is offered to the birth cohort of Year 7 students every year (e.g. for 2012, Year 7 students are born between 1 July 1999 and 30 June 2000). General practices should offer these vaccinations only when a Year 7 student did not access it through the school program. This may have been because they were absent from school the day the vaccinations were given.

What vaccinations are offered to children in the Year 7 school immunisation program?

Vaccine Brand Supplied Disease Prevented

Hep B

H-B-Vax II (Adult)

Hepatitis B

dTpa

Adacel

Diphtheria, Tetanus, Pertussis

VZV

Varilrix

Varicella (chickenpox)

HPV (females only)

Gardasil

Human Papilloma Virus (HPV)

What is the current Year 7 school immunisation program schedule?

School Term Vaccine Dose

Term 1

Hep B

HPV

Dose 1

Dose 1

Term 2

Varicella

HPV (Dose 2)

 

Dose 2

Term 3

Hep B (Dose 2)

dTpa

Dose 2

Term 4

HPV (Dose 3)

Dose 3

What paper work needs to be completed by general practices after the Year 7 school vaccination program vaccinations have been administered?

The sustained affordability of this arrangement is dependent on GPs ensuring that the vaccines are used only in the eligible cohort.  School-based vaccinations should be given by the school-based team in the first instance. After administering vaccines obtained for use in the Year 7 School Vaccination Program, GPs should fax a completed Report of Government-Procured Vaccines used in General Practice for Adolescents and Adults to the Communicable Disease Control Directorate on 9388 4877. Forms are available on the Department of Health website  (Health Promotion code: HP12088)

How can practice staff determine if a child has been vaccinated at school?

  1. Practice staff can ask the parents which vaccines their child has received.
  2. The parents of children vaccinated at school are sent a note advising which vaccine/s their child has received.
  3. If a child is absent from school on the day of vaccination, the parents will be sent a letter from the school. The parents should bring this letter to the general practice when seeking catch-up vaccinations.
  4. If practice members are still unsure what to give, they should telephone the Central Immunisation Clinic on 9321 1312. The clinic can advise which vaccines the child has received at school.

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Young people target of 2012 chlamydia campaign

More than 12,000 Western Australians are expected to contract chlamydia this year.

WA Health’s 2012 chlamydia campaign aims to increase testing for this sexually transmitted infection among 16 to 29 year olds—the age group for which incidence of infection is consistently highest. It also aims to raise awareness of safe sex practices among this demographic.

Medical practitioners are urged to offer opportunistic chlamydia testing to all people in this age bracket who present at their practices.

Tracing the sexual contacts of people with chlamydia is important in limiting the spread of chlamydia in the community and for preventing re-infection of patients by asymptomatic partners.

w:       couldihaveit.com.au (external site)

Free online professional development for doctors and practice nurses  

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Health accolade for online program

The online chlamydia testing program received the ‘Excellence in Prevention, Promotion and Early Intervention Award’ at the WA Health Awards in November last year. 

Chlamydia is the most commonly notified disease in Australia and 84% of notifications in Western Australia in 2010 occurred in people aged under 30 years.

The online testing program was developed to increase young people’s access to chlamydia testing by allowing participants to be tested for chlamydia without visiting a doctor.

Launched in February 2010, the program is funded by the Communicable Disease Control Directorate and supported by the B2 Clinic at Fremantle Hospital.

Program participants complete an online risk self-assessment which generates a downloadable laboratory request form. They then present to a Pathwest laboratory with the form and submit a urine sample or self-obtained lower vaginal swab for chlamydia testing.

Participants also receive education, referral for treatment and the opportunity to complete an online satisfaction survey.  More than half (56%) of the 675 pathology forms downloaded resulted in a test and chlamydia was detected in 18% of those tested.

The majority of tests were undertaken for males (55%) and people younger than 30 years (71%). All participants with a positive test result underwent appropriate clinical management. Half were treated within 7 days of specimen collection. Participant satisfaction with the program was high with 98% saying they would recommend the service to a friend.

The online program demonstrates that internet-based screening for chlamydia is an effective means of increasing access to testing among young people at risk of STIs and is a valuable addition to opportunistic, clinic-based strategies.

See  couldihaveit.com.au (external site) for more information.

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Guidelines for managing STIs – now available for your iPad

WA Health’s Guidelines for Managing Sexually Transmitted Infections, better known as the “Silver Book”, can now be downloaded to your iPad.

The guidelines can be downloaded at silverbook.health.wa.gov.au and include links to updated versions of three desktop resources that assist health professionals with specimen collection, STI testing and STI management. 

Note, the Quick Guide to STI Testing has been amended to say that a sexually active Aboriginal young person aged under 35 years should be tested for chlamydia and gonorrhoea. Previously, the recommendation was for testing to be done on sexually active women 25 years or younger.

Print versions of the updated supplementary resources have been distributed to all general practitioners and other health care providers.  Further copies can be obtained by telephoning the Sexual Health and Blood-borne Virus Program on 9388 4841.

* Adapted from the New South Wales STI Programs Unit’s resources.

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Free hepatitis vaccines for at-risk groups

The WA Department of Health provides free hepatitis A and hepatitis B vaccines to patients newly notified with hepatitis C.

On receipt of a new hepatitis C notification, the Department of Health posts a letter and vaccine order form to the notifying medical practitioner. The practitioner should discuss the risks and benefits of vaccination with the patient and, if the patient agrees to vaccination, determine the appropriate schedule—standard or accelerated.

Completed order forms should be returned by fax to the Department of Health.

View Department of Health guidelines for this vaccine program.

Further information can be obtained by telephoning the Sexual Health and and Blood-borne Virus Program’s medical adviser, Dr Donna Mak on 9388 4828 Monday, Tuesday or Thursday.

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