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Objectives: To investigate the attitudes of general practitioners (GPs) to varicella disease and varicella vaccine.
Methods: A cross-sectional questionnaire was mailed to GPs in Fairfield (located in the south-western suburbs of Sydney, NSW, Australia) to identify attitudes about varicella vaccine, previous experience with varicella disease and the likelihood of prescribing varicella vaccine.
Results: Of 239 questionnaires issued, 160 were returned (67%). The majority (72%) of respondents agreed that varicella vaccine should become part of the immunization schedule. However 12% of GPs did not support vaccination for varicella as they considered it to be a benign self-limiting disease. Respondents who had experience with varicella complications were significantly more likely to recommend universal vaccination (OR 3.36; 95% confidence interval (CI) 1.38−8.19) whereas those respondents who were concerned about side effects of the vaccine were less likely to recommend universal vaccination (OR 0.31; CI 0.15−0.63).
Conclusions: The majority of GPs are receptive to varicella vaccination becoming part of the immunization schedule. Experience with varicella complications is associated with recommending universal varicella vaccination. General practitioners in this cohort do not consider varicella to be a benign disease, but they are concerned about possible unknown side effects of the vaccine. Public health measures for introducing universal vaccination need to address these concerns.
Varicella (chickenpox) is a common contagious disease of childhood, caused by primary infection with Varicella zoster virus (VZV). An estimated 240 000 cases of VZV infection occur annually in Australia1. Of these, most are mild and self-limiting; however, serious life-threatening complications can occur, particularly in adults and immunocompromised individuals2.
Although it is part of the routine vaccination schedules in Canada and the USA, varicella vaccine in Australia is an additional, optional vaccine. As such, it requires initiation by either parent or general practitioner (GP) and, therefore, prior knowledge of its availability, efficacy and safety. The cost to parents is approximately A$60−A$70, not reclaimable on Medicare. Its use results in an extra injection being required after 12 months of age. The vaccine was licensed in the USA in 1995 and in Australia in 2000.
In Australia, the vast majority of vaccines are administered within GP surgeries and GPs still constitute an important source of information and guidance to the primary care givers of children3. Their attitudes, therefore, have a significant influence in the uptake of an extra, non-scheduled vaccination such as varicella. The purpose of the present study was to investigate the attitudes of GPs to varicella, the disease and its vaccine, and in doing so to identify possible barriers to the uptake of vaccination within the community. The study was carried out in Fairfield (population 191 000), a low socio-economic area in south-western Sydney with a large ethnic population4. Fairfield has characteristically low vaccination rates, with 81% of preschool children being fully vaccinated (Health Insurance Commission Immunisation statement, pers. comm., May 2001).
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All 239 GPs known to the Fairfield Division of General Practice (FDGP) were mailed an eight-item questionnaire in March 2001. This questionnaire was contained on both sides of an A4 sheet of paper. It was divided into three parts. The first consisted of five simple demographic questions regarding their practice. The second asked about their experience of varicella disease and, from a list of seven complications of varicella, asked them to circle any they had witnessed. A separate question asked if any of their patients with varicella had been admitted to hospital. The third part consisted of a list of eight statements about varicella disease and vaccination (Table 2) with a Likert scale of five responses, from ‘strongly agree’ to ‘strongly disagree’. There was a ‘no comment’ option, and below this was a space for other comments.
A pilot study was performed on a group of four GP trainees. Alterations were made to the questionnaire, resulting in the final format, which was timed to take 5 min to complete.
The questionnaire was accompanied by a covering letter explaining the purpose of the study and offering an incentive of entering a prize draw for a bottle of wine for responses returned. The survey had the support of the Fairfield Immunisation Taskforce and the FDGP and was sent out with the newsletter of the Division.
A second mail-out was carried out to all initial non-respondents 3 weeks after the first. Two weeks after this all remaining non-respondents who had fax machines were faxed copies of the questionnaires. Information was obtained from the FDGP in order that the characteristics of respondents and non-respondents could be compared.
Data was analysed using spss software (version 7.0; spss, Chicago, IL, USA) for descriptive statistics and Epi Info (version 6.04b; Centers for Disease Control and Prevention, Atlanta, GA, USA) to calculate odds ratios (OR). For multivariate analysis, Likert responses were reduced to dichotomous variables: ‘completely agree’/‘agree’ versus any other response (including ‘no comment’ responses). Confounding variables, such as whether the respondent was a solo practitioner or not, or how many children were seen in a day, were included in the analysis.
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Of the 239 GPs contacted, 160 questionnaires were returned, giving a response rate of 67%. Table 1 outlines the demographic characteristics of the respondents and the complications of varicella disease witnessed by the respondents. There were no significant differences between respondents and non-respondents with regard to whether they were men or women, or whether they were in solo practice or not.
Table 1. Demographic characteristics of respondents
|Characteristic||n = 160 (%)|
|Solo Practitioner||76 (46)|
|No of children seen per day|
|Who administers vaccine|
|Both Doctor and Nurse||5 (3)|
|Ever Prescribed vaccine||127 (79)|
|Stocks vaccine||29 (18)|
|Complication witnessed of varicella (≥1)||46 (29)|
|Acute Cerebellar Ataxia||6 (4)|
|Necrotising Fascitis||2 (1.3)|
|Admitted patient to hospital with varicella||43 (27)|
From the Likert responses to statements about varicella vaccine, 72% of respondents agreed that varicella should be part of the immunization schedule, whereas only 12% agreed that there was no need to vaccinate against varicella as it was a benign, self-limiting disease (Table 2). Fifty-eight per cent of respondents had no concern that universal vaccination would lead to more serious disease in adults, whereas 62% of respondents disagreed that universal vaccination would lead to an increase in Herpes zoster in later life. Respondents were concerned about possible unknown side effects of the vaccine (36%) and its long-term immunity (44%). Important objections to varicella immunizaton were the administration of another injection (28%) and the cost to parents (77%).
Table 2. Agreement with statements about varicella vaccine
|Statement||Agree/Strongly agree No. (%)||Neither agree nor disagree No. (%)||Disagree/Strongly disagree No. (%)||No comment No. (%)|
|Varicella vaccine should be part of the immunization schedule||115 (72)||28 (18)||13 (8)||4 (2)|
|There is no need to vaccinate against varicella as it is a benign, self-limiting disease||19 (12)||14 (9)||122 (76)||5 (3)|
|Vaccination will lead to more serious disease in adults||27 (17)||29 (18)||92 (58)||12 (7)|
|Vaccination will lead to an increase in Herpes zoster in later life||15 (9)||29 (18)||99 (63)||17 (10)|
|I am concerned about possible, unknown side effects of the vaccine||57 (36)||55 (34)||35 (22)||13 (8)|
|Vaccine immunity may not be life-long||71 (44)||42 (26)||29 (18)||18 (12)|
|Another needle will act as a deterrent to uptake of the vaccine||45 (28)||33 (20)||65 (41)||17 (11)|
|Cost-to-parent is a deterrent to uptake of the vaccine||123 (77)||15 (9)||14 (9)||8 (5)|
Factors that were associated with agreement with the statement that ‘varicella vaccine should become part of the immunization schedule’ are outlined in Table 3. Factors that reached statistical significance were the following: experience with prescribing the vaccine (OR 3.76; 95% CI 1.69−8.37), witnessing pneumonia (OR 3.78; 95% CI 1.25−11.4) or any complication of varicella (OR 3.36; 95% CI 1.38−8.19). All respondents who had witnessed encephalitis as a complication of varicella (n = 15) recommended universal vaccination.
Table 3. Characteristics associated with recommending universal varicella vaccination
|Characteristic||OR (95% CI)|
|Witnessing any complication of varicella disease||3.36 (1.38−8.19)|
|Witnessing pneumonia as a complication of varicella disease||3.78 (1.25−11.4)|
|Ever prescribed varicella vaccine||3.76 (1.69−8.37)|
|Agreement with concerns about possible, unknown side effects of varicella vaccine||0.31 (0.15−0.63)|
|Agreement with concerns that vaccine immunity may not be life-long||0.60 (0.3−1.21)|
|Agreement with concerns that vaccination will lead to an increase in Herpes zoster in later life||1.08 (0.33−3.6)|
|Agreement with concerns that vaccination will cause more serious varicella disease in adults||0.92 (0.37−2.27)|
|Agreement that cost-to-parent is a deterrent to vaccination||1.54 (0.70−3.38)|
|Agreement that another needle is a deterrent to vaccination||0.79 (0.33−1.49)|
|Practitioner stocking the vaccine||0.83 (0.36−1.92)|
|Doctor administering the vaccine||1.71 (0.53−5.56)|
|Solo practitioner||1.00 (0.50−2.01)|
Conversely, those who were concerned with possible, unknown side effects of the vaccine (36% of respondents) were less likely to recommend universal vaccination (OR 0.31; 95% CI 0.15−0.63). Forty-four per cent of respondents were concerned about the long-term efficacy of the vaccine. However, this did not impact in a statistically significant way on whether they would recommend universal vaccination.
Confounding variables such as whether the respondent was a solo practitioner, or the number of children seen per day had no effect on the associations listed.
Other possible negative outcomes of varicella vaccination, such as an increase in Herpes zoster in later life following vaccination, or more serious disease in adults, did not deter the majority GPs from recommending universal vaccination.
The ‘cost-to-parent’ of the vaccine and an ‘extra needle’ were cited as deterrents to the uptake of varicella vaccine by 77% and 28% of respondents, respectively. However there was no statistically significant association between these concerns and recommending universal vaccination.
Agreement with recommending universal vaccine was not associated with demographic factors, such as whether the respondent was a solo practitioner, the number of children seen, who administers the vaccine, or whether the respondent stocks the vaccine or not.
Fifteen per cent of respondents (n = 25) made a comment at the end of the questionnaire. These comments were wide-ranging. The most common were concerns raised regarding the long-term efficacy of the vaccine (6/25).
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The results of the present study show that GPs included in this survey are strong proponents for varicella vaccination. Recommending universal vaccination was particularly influenced by personal experience of complications, such as encephalitis and pneumonia.
Although respondents were concerned about possible, unknown side effects of the vaccine (36%), and of the long-term efficacy of the vaccine (44%), on the whole they would still recommend universal vaccination. Negative outcomes such as more serious disease in adults and an increase in Herpes zoster in later life after vaccination were not significantly associated with not recommending universal vaccination.
These results are in contrast to the findings of a similar study surveying Paediatricians in the USA (Newman et al.)5. In the USA study, universal vaccination was recommended by only 44% of respondents. As with the present study, personal experience of complications, particularly encephalitis, was strongly associated with recommending universal vaccine.
Regarding the possible side effects of the vaccine, few serious adverse events have been observed6. The debate continues concerning life-long immunity conferred by varicella vaccine and the possibility of contracting varicella disease in adult life if vaccine-induced immunity wanes, also whether this cohort will be at risk of either more frequent or more severe zoster than persons with naturally acquired varicella immunity7,8. At present, the evidence based on 20 years experience with the vaccine indicates that vaccine-induced immunity persists9, and that vacinees are less likely to develop zoster than are age-matched controls who had natural immunity10.
In Australia, varicella vaccination is optional, has to be paid for and results in another injection. The present study demonstrated that these factors are a concern for GPs. This aligns with previous studies on the subject3. In Australia, varicella vaccine is likely to become part of the immunization schedule within the next 2 years11. In addition, it is planned to vaccinate all 12-year-old children11. Initially the vaccine will be given as a separate injection at 18 months of age.
The other major deterrent to vaccination identified was the ‘cost-to-parents’. Once varicella becomes part of the immunization schedule, this will cease to be a factor.
The response rate of 67% may have introduced a possible source of bias in the present study; however, we were not able to find significant differences between respondents and non-respondents.
The present study was carried out in a small area of south-western Sydney which may affect its generalizability. However as a low socio-economic area with characteristically low immunization rates, it represents the type of area that must be targeted once universal immunization is established.
In summary, GPs in the Fairfield area are receptive to the recommendation for universal varicella vaccination. They do not think that it is a benign disease, and if they do have concerns these are confined to possible side effects of the vaccine and its long-term efficacy.
Public health initiatives for introduction of the vaccine should focus on dealing with these concerns. Results from the present study have been presented at the recent Public Health Association Conference and to the Australian Immunization Task Force.