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Response of Australian veterinarians to the announcement of aHendra virus vaccine becoming available

D Mendez,a* P Büttnera,b and R Spearea,b

Design   A cross-sectional study of private veterinarians providing

equine services in Queensland.

Results   The study revealed that a majority of veterinarians would

support the introduction of a Hendra virus (HeV) vaccine. Moreover,

almost half of the respondents intended to make vaccination a

prerequisite to horse patient presentation. However, participants

also responded that a vaccine would not reduce the risk sufficiently

to cease or downgrade their HeV management plan and infection

control measures.

Conclusion   When devising promoting and marketing cam-

paigns, government agencies and manufacturers should consider

private veterinarians’ intentions as a significant driver for the

uptake of the HeV vaccine.

Keywords   biosecurity; Hendra virus; infection control; vaccines;

veterinarians

Abbreviations   ARIA, Accessibility/Remoteness Index of Aus-

tralia; EVA, Equine Veterinarians Association; HeV, Hendra virus;

QLD, Queensland

 Aust Vet J  2013;91:328–331 doi: 10.1111/avj.12092

Since the emergence of Hendra virus (HeV) in Queensland

(QLD), Australia, in 1994, there have been 38 outbreaks that

have resulted in the death of 81 horses, 7 human infections and

4 human deaths.1–7 Horses become infected when the virus spills over

from pteropid bats and humans become infected when exposed to the

bodily fluids of an infected horse.1,8 Recently, a dog was found to be

infected by HeV without showing any clinical signs.9 HeV has low 

infectivity in horses and humans, but a high mortality rate in both

species (75% and 57%, respectively).1 Consequently, HeV is consid-

ered a high occupational risk for all people coming into contact with

potentially infected horses. Veterinarians are particularly vulner-

able and have been encouraged to upgrade their infection control

standards to effectively mitigate HeV-related occupational risks for

themselves, their staff and clients. However, the legal ramifications of inadequately managing this new zoonotic risk have proven too threat-

ening for some private veterinarians who have chosen to cease equine

practice.10

The announcement of a HeV vaccine for horses becoming avail-

able meant that equine HeV infections, and consequently human

HeV infections, could soon be preventable.11,12 The marketing of 

this vaccine to veterinarians and horse owners should therefore be

straightforward, because HeV risks to both horse and human health

would greatly decrease if vaccination coverage was sufficiently high.

However,would this engender a relaxing or cancellation of HeV man-

agement plans and related infection control in private practices in

QLD? Would accessibility to a vaccine be sufficient to encourage

 veterinarians back into providing equine services?

In 2011, as part of a two-part cross-sectional study of private veteri-

narians registered in QLD, we asked how the introduction of a HeV

 vaccine would affect their practice.Here we present the results for this

subset of the study and the hypothetical implications on the uptake of 

the vaccine by private veterinarians.

Materials and methods

With the approval of the James Cook University Human Ethics Com-

mittee (Ethics Approval No. H3687), we conducted a postal survey of 

all veterinarians working in private practice and registered in QLD,

between June and September 2011. Participants were eligible to fill in

the HeV risk management specific questionnaire if they had provided

equine veterinary services at least once in the previous 12 months.

Participants were asked multiple choice and open-ended questions

that had been validated within the target population. The question-

naire was designed to further investigate issues brought to light by aseries of in-depth interviews carried out with private veterinarians

in QLD in 2010.10 The questionnaire was revised twice after being

administered to two different groups of three known QLD equine

practitioners who provided feedback on the relevance of the questions

asked. Prospective respondents were sent three rounds of reminders

2–3 weeks apart. One of the multiple choice questions asked what

participants would do if a HeV vaccine for horses was available.

Statistical analysis

Quantitative data were analysed using SPSS for Windows, version 19

(IBM SPSS, Chicago, IL, USA). Categorical data were described using

percentages. Numerical data were described using mean and standarddeviation (SD). Comparisons between participants who responded

‘yes’ to the hypothetical HeV vaccine questions and those who

responded ‘no’ with respect to geographic location and Accessibility/

Remoteness Index of Australia (ARIA) classification were conducted

using Fisher’s exact tests and exact Chi-square tests for trend. The

assumptions of these tests were met. Multivariable logistic regression

analyses were conducted to assess the effects of geographical location,

as well as ARIA classification, on the responses to three hypothetical

questions related to the availability of a HeV vaccine. The results of 

these six multivariable analyses were adjusted for confounding. All

demographic characteristics of the respondents, as well as those of 

*Corresponding author.aAnton Breinl Centre for Public Health and Tropical Medicine, James Cook University,

 Townsville 4810, Queensland, Australia;  Diana.Mendez@jcu.edu.aub Tropical Health Solutions P ty Ltd, Townsville, Queensland, Australia

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their practices, were checked for potential confounding factors. A

characteristic was identified as a confounder if it changed the estimate

in the model by more than 5%.

Results and Discussion

Of the 1604 eligible private veterinarians registered in QLD, a total of 204 (12.7%) self-selected as having treated at least one horse in the

previous 12 months and returned the questionnaire for the present

study. As the total number of equine veterinarians in QLD was

unknown,the response rate could not be calculated. However, in 2010

the QLD branch of the Equine Veterinarians Association (EVA)

counted 219 members (Bruce Pott, pers. comm.). Although, not all

equine veterinarians are member of the EVA, the 204 respondents

may represent in fact a high proportion of the total number of equine

 veterinarians in QLD. Among these 204 respondents, 51.5% (105)

were female, a higher percentage than reported previously (20%),

which may be related to the overall increase in female representation

in the veterinary profession in more recent times.13,14 Overall,

57% (116) of respondents were aged 40 years or younger, the majority 79.0% (154) worked in mixed practices and 88.7% (180) worked

full-time. The mean (±  SD) number of hours worked per week was

46.9  ±  13.2 (range 5–90). One-third (34.3%) resided in the Brisbane

and Moreton statistical districts. According to the ARIA classifica-

tion,15 the majority of participants were from highly accessible to

accessible areas (73.5%). Most participants (76.1%) provided equine

 veterinary services on at least a weekly basis to a range of equine

premises and more than half (64.1%) had dealt with at least one

potential case of HeV (Table 1).

A high proportion of veterinarians (153/191, 80.1%; 13 did not answer

the questions related to HeV vaccine) would still consider HeV a high

risk in equine practice even if a vaccine was to become available. Thismay be because of the unknown level of vaccination coverage. Also,

horses have been shown to shed the virus up to 3 days before devel-

oping clinical signs, so HeV would continue to be a high risk prior to

the development of an immune response.16 None of the participants

intended to terminate their HeV risk management plans. However,

only 76.5% reported to have such plan in place (Table 1). This is a

higher percentage (68%) than was reported by Workplace Health and

Safety QLD in 2010, a possible indication that more veterinarians

are implementing the necessary infection control changes to better

mitigate the risks of HeV.17 Only 16 (8.4%) respondents would be

less concerned about implementing infection control. These results

demonstrate that even with the availability of the HeV vaccine, veteri-

narians would still use a cautionary approach when dealing withhorses and very few would relax their infection control measures.

In 2010, audits conducted by Workplace Health and Safety Queens-

land reported that HeV management in equine practices was still not

optimal. However, there has not been a human case recorded since

September 2009,1 which may reflect an improvement in veterinarians’

attitudes towards infection control in general and HeV risk manage-

ment in particular. Finally, 88 (46.1%) respondents would require

horses that were presented for examination to be vaccinated. A HeV

 vaccine would therefore be well received by the veterinarians who

could become the main advocates of vaccination uptake by horse

owners.

Table 1.   Demographic and professional characteristics of 204 partici-

pants and their veterinary practices*

Characteristic Frequencies(relative

frequencies)

SexFemale 105 (51.5%)

Male 99 (49.5%)

Age

≤40 years 116 (56.9%)

>40 years 88 (43.1%)

Geographic distribution

Residing in Brisbane or Moreton 70 (34.3%)

Not residing in Brisbane or Moreton 134 (65.7%)

ARIA categoriesa

Highly accessible–Accessible 150 (73.5%)

Moderately accessible 31 (15.2%)

Remote–Very remote 23 (11.3%)

Education

With veterinary degree from:

QLD university 158 (78.2%)

Australian university (not QLD) 25 (12.4%)

Overseas 19 (9.4%)

Professional profile/role in practice

Role in the practice

Principal 75 (37.7%)

Partner/Associate 20 (10.1%)

Employee 103 (51.8%)

Placement 1 (0.5%)

Full-time practising 180 (88.7%)

Part-time practising 24 (11.3%)

Practice type

Large animals only 32 (16.4%)

Mixed 154 (79.0%)

Other (specialised clinics) 9 (4.6%)

Frequency of veterinary services provided to horses

Daily–weekly 153 (76.1%)

Monthly 26 (12.9%)

Yearly or on call/after hours 21 (10.5%)

Recently ceased equine practice 1 (0.5%)

HeV experience

Had dealt with a potential case of HeV 127 (64.1%)

Had not dealt with potential case of HeV 77 (35.9%)

HeV preparedness

Had a HeV management plan 156 (76.5%)

Did not have a HeV management plan 29 (14.2%)

Didn’t know 7 (3.4%)

*Not all participants answered all questions.aAccessibility/Remoteness Index of Australia (ARIA) categories aredefined by a range of ARIA index scores based on the road distancefrom the closest service centres.HeV, Hendra virus; QLD, Queensland.

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There were no significant differences in participants’ responses across

all professional profiles and demographic characteristics, except when

it came to geographic distribution, for which there appeared to be a

trend showing that veterinarians in south-east QLD and those in areaswith good accessibility to services may not have the same approach to

a HeV vaccine as other veterinarians (Table 2). This may be because

their HeV risk perceptions aredifferentor that they canforesee uptake

of the HeV vaccine by their clients to be different. The latter is an

important factor for private veterinarians who, unlike medical prac-

titioners for human health, run private businesses driven by the end-

users. Although the sample size was limiting in this study, this trend

should be further investigated, because it may help the government

and manufacturers to better target their promotion and marketing

strategies of the HeV vaccine.

We also asked veterinarians who had recently ceased equine practice

because of HeV-related risks if access to a HeV vaccine would make

them overturn their decision. Only one participant reported to have

recently ceased equine practice (Table 1). Our study may not have

captured those who had recently ceased equine practice or those who

only saw horses on an irregular basis, as they may have thought the

survey did not apply to them. It is therefore difficult from these results

to corroborate thetrend we reported previously or to evaluate if access

to a HeV vaccine would reverse this trend.10

Conclusions

Although the introduction of a HeV vaccine would arguably reduce

the risk to animal and human health, veterinarians did not perceive

equine immunisation as a panacea against HeV and did not intend to

decrease protective strategies when dealing with horses. In addition,

many were prepared to require horse owners to vaccinate their horses

as a condition for them to be presented, so veterinarians could bestrongdrivers fora high uptake of the HeV vaccine.This factor should

be considered when government and vaccine manufacturers are

looking at developing promotion and marketing strategies for the

HeV vaccine.

Acknowledgments

Ourthanks to SusanReillyfor assisting with data entry.Thisstudywas

carried out with the approval of James Cook University Human Ethics

Committee permit no.H3687 and was financially supported by Anton

Breinl Centre Wildlife Services Fund.

References

1. Department of Agriculture, Fisheries and Forestry. Hendra virus.   http://

daff.qld.gov.au . Accessed July 2012.

2. Murray K, Selleck P, Hooper P et al. A morbillivirus that caused fatal disease in

horses and humans. Science 1995;268:94–97.

3. Murray K, Rogers R, Selvey L et al. A novel morbillivirus pneumonia of horses

and its transmission to humans. Emerg Infect Dis  1995;1:31–33.

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6. Hanna JN,McBrideW, Brookes DL et al. Hendravirus infectionin a veterinarian.

Med J Aust  2006;185:562–564.

Table 2. Geographic distribution characteristics of 204 participants and their veterinary practices stratified by response to hypothetical vaccination

questions*

Geographic distributioncharacteristics

If a HeV vaccine for horses wasavailable, would you still consider

HeV a high risk for equine practice?

If a HeV vaccine for horses wasavailable, would you require all horses

you examine to be vaccinated?

If a HeV vaccine for horses was available,would you be less concerned about

implementing infection control?

Yes (n  =  153) No (n =  38) P value Yes (n =  88) No (n  =  103) P value Yes (n =  16) No (n  =  175) P value

SE-QLD vs rest of QLD 0.037a 0.069a 0.098a

0.015b 0.014e 0.035f 

Residing in Brisbaneor Moreton

48 (31.4%) 19 (50.0%) 37 (42.0%) 30 (29.1%) 9 (56.3%) 58 (33.1%)

All other statisticaldivisions

105 (68.6%) 19 (50.0%) 51 (58.0%) 73 (70.9%) 7 (43.8%) 117 (66.9%)

ARIA categories 0.030c

0.031d0.440c

0.272e0.204c

0.250f 

Highly accessible 60 (39.2%) 21 (55.3%) 42 (47.7%) 39 (37.9%) 8 (50.0%) 73 (41.7%)

Accessible 46 (30.1%) 14 (36.8%) 24 (27.3%) 36 (35.0%) 7 (43.8%) 53 (30.3%)

Moderately

accessible

27 (17.6%) 1 (2.6%) 12 (13.6%) 16 (15.5%) 0 28 (16.0%)

Remote 13 (8.5%) 0 6 (6.8%) 7 (6.8%) 1 (6.3%) 12 (6.9%)

Very remote 7 (4.6%) 2 (5.3%) 4 (4.5%) 5 (4.9%) 0 9 (5.1%)

*Not all participants answered all questions. Results are from bivariate and multivariable analyses.aP value relates to Fisher’s exact test results;  bresult of multivariable regression analysis adjusted for the confounding effect of working hours perweek;  cresult of exact Chi-square test for trend;  dresult of multivariable regression analysis adjusted for the confounding effect of sex and age of respondent; eresult of multivariable regression analysis adjusted for the confounding effect of sex and number of full-time veterinarians workingin practice of respondent;  f result of multivariable regression analysis adjusted for the confounding effect of country where Bachelor degree wascompleted and working hours per week.

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7. Perkins N. Independent review of Hendra virus cases at Redlands and Proserpine

in July and August 2008. http://www.tropicalhealthsolutions.com/HeVreports.

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9. Symons R. Re: canine case of Hendra virus and Hendra virus vaccine. Aust Vet J 

2011;89(10):N24.

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veterinarians, Queensland, Australia. Emerg Infect Dis 2012;18:83–85.11. Pallister J, Middleton D, Wang F et al. A recombinant Hendra virus G

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Accessed July 2012.

13. Heath TJ. Australian veterinarians who work with horses: an analysis. Aust Vet 

2004;82:340–345.

14. Heath TJ. Number, distribution and concentration of Australian veterinarians

in 2006, compared with 1981, 1991 and 2001. Aust Vet J  2008;86:283–289.

15. Australian Institute of Health and Welfare. Rural, regional and remote health: a

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17. Workplace Health and Safety Queensland, Dept of Justice and Attorney-General, Queensland Government.   Summary report: outcomes of an audit of 

Hendra virus risk management in the veterinary industry . PN1 Version 1. Last

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(Accepted for publication 17 March 2013)

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