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Compulsory and non-compulsory immunizations: Contraindications perceived by medical practitioners

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Page 1: Compulsory and non-compulsory immunizations: Contraindications perceived by medical practitioners

Papers Compulsory and non-compulsory immunizations: contraindications perceived by medical practitioners

C a r l a Z o t t i * , P a o l a S i l v a p l a n a , S a v i n a D i t o m m a s o , R o b e r t o R u s s o a n d A n g e l a M o i r a g h i R u g g e n i n i

A total of 284 9eneralpractitioners (GPs), paediatricians and doctors of public vaccination centres (DPVC) were interviewed to investioate their willingness to immunize children with compulsory (diphtheria-tetanus, oral polio) and non-compulsory (measles, pertussis) vaccines in the presence of 19 different medical histories. We observed a reluctance to immunize in the case of false contraindications, a lack of information mainly about non-compulsory immunizations, and doubts about the real contraindications to polio, measles and pertussis vaccines. The frequency of correct answers to the question posed was significantly hioher in the 9roup with less than 20 years of experience, and the DPVCs proved better informed about immunization. However, the crucial role played by the GPs and paediatricians' advice can prejudice the correct use of active immunization.

Keywards: Contraindications; vaccination; perceptions of medical practitioners

I N T R O D U C T I O N

The need to increase the use of measles and pertussis immunization in Italy is a subject of great interest to health officials, and it is thus important to evaluate physicians' perceptions of contraindications to immunization.

A study to evaluate practitioners' opinions about the main contraindications to measles immunization was carried out in England in 19851 . The results showed that the distinction between contraindications to measles and pertussis vaccines was not clear, in particular in relation to their composition or to their use in immunosuppressed subjects. A second, similar study was carried out in 1986 in the Health District of Nottingham 2, where 278 GPs were asked to complete a questionnaire in order to evaluate their opinions and knowledge about measles immunization. A similar questionnaire with the same purpose had been distributed one year earlier in the same district to health visitors and clinical nurses 3.

The national health service in Italy is structured in local health units, covering from 30 to 150000 people. Each local health unit has one or more doctors of public vaccination centres (DPVC) as members of the public health service and a maternal and child health service; these are responsible for vaccinations.

In Italy vaccinations are differentiated as compulsory or voluntary. Diphtheria, polio and tetanus vaccinations are mandatory for everybody; tuberculosis and typhoid

Dipartimento di Igiene e Medicina di Comunita. (Department of Hygiene and Community Medicine), Via Santena 5bis, 10126 Torino, Italy. *To whom correspondence should be addressed. (Received 8 January 1991; revised 14 February 1992; accepted 14 February 1992)

0264-410)(/92/110742-05 © 1992 Butterwo~h~-Ieinemann Ltd

742 Vaccine, Vol. 10, Issue 11, 1992

vaccinations are mandatory for selected groups; pertussis, measles and rubella are voluntary vaccinations recommended by the Ministry of Health.

All public health services administer the compulsory vaccinations, while only some of them offer the voluntary vaccinations. Measles, pertussis and rubella vaccinations are often administered by general practitioners and paediatricians, but these recommended vaccinations are not always registered at the local health units. Epidemiological studies indicate that 15% of Italian children received vaccinations for measles and pertussis in 19864; in the Piedmont region data collected during the recent (1989-1991) measles vaccination campaign indicated that 36% of children under 9 had already been vaccinated. A study of kindergartens in 19885 indicated that 15% of children were vaccinated for pertussis.

In Italy, non-compulsory vaccinations are usually given on the advice of the general practitioner or paediatrician, which will also affect the scheduling of the compulsory vaccinations. It is therefore important to investigate the opinions of physicians on vaccinations, both compulsory (diphtheria-tetanus (DT) and oral polio vaccine (OPV)) and non-compulsory (measles, pertussis ).

M E T H O D

A total of 220 general practitioners (GPs), 30 paediatricians and 50 DPVCs from ten local health units in Piedmont (300 physicians in all) were asked to complete a questionnaire during a compulsory refresher course. They represented almost all the medical staff in these local health units, though a real randomization was not performed. In the city of Turin (the largest city in

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Immunization: perceived contraindications: C. Zotti et al.

Graduat ion (year ) . . . . . . . . . .

number of p a t i e n t s . . . . . . . . . .

sex [ ] [ ] U.S,S.L. # . . . . . . . . . . .

Doc to r of Pub l i c Vacc ina t i on Cent re

General P r a c t i t i o n e r

P e d i a t r i c i a n

F451

F451

Main area of a c t i v i t y u r b a n

r u r a l

both

[ ] [ ]

[ ]

1 ACUTERESPRATORY ILLNESS WI'R-IOUTFEYER 2 FEBRILE ILLNESS 3 ASTHMA 4 ECZEMA $ ALLERGIC TO HEN$' EGGS 6 SENSITlYE TO NEOMYCIN 7 RECEIYNG IIvMJNOSUPPRESSI~IGTREATMENT $ RECEIYI~IGORALSTEROIDS 9 HJ.Y. POSITWEBABY 10 DIARRHOEA 11 CHRONIC DIARRHOEA 12 EYOLYING NEU ROLOG ICAL DISEASE 13 FEBRILE CONYULSION S 14 NEUROLOGICAL DEFICIT 15 EPILEPSY OR FAMILY EPILEPSY 16 CHILD DELIYERED PREMATURELY 17 CHRONIC LUNG DISEASE 111 CHRON IC HEART DISEASE 19 MOI'HER OF CHILD IS PREGNANT

DT = Diphteda-Tetanus vaccine M = Measles vaccine OPV = Oral Polio vaccine P = Pertussis vaccine

DT WOULD 3PY M P

VACCINE TO BE GIVEN

W OULD N OT POST PONE NOT KI4 OWN

DT OP¥'M P )T OP¥ M P DT OP¥ M P

Figure 1 Questionnaire submitted to medical practitioners

Piedmont) the questionnaire was submitted individually by a trained interviewer to 100 paediatricians randomized among the 163 of the national health service.

The first half of the questionnaire concerned experience," number of patients, specialization and activity area (urban or rural). The second half listed 19 possible contraindications to DT, OPV, measles and pertussis immunization (Figure 1 ). The respondents were required to mark whether they 'would' or 'would not' give the vaccine, would 'postpone it' or 'do not know'. Only one answer for each contraindication was considered correct, as shown in Table 1. World Health Organization guidelines were followed in order to assign 'correct' or 'incorrect' values to contraindications listed for each vaccine 6-9. Recently WHO directions have been adopted in Italy by the circular 'Public Health Guidelines 'a° .

The ratio of correct answers given to the maximum possible number of correct answers (19 replies multiplied by the number of respondents ) was calculated. Statistical

analysis was performed with the Z 2 test and the multiple logistic analysis.

R E S U L T S

Of the 284 questionnaires returned, 131 were from 220 GPs, 111 from paediatricians (100 from oral interviews and 11 from 30 paediatricians asked to complete the questionnaire) and 42 from 50 DPVCs.

The distribution according to experience was: 5 % with more than 40 years' experience, 19.8% between 21 and 40 years, 38.1% between 10 and 20 years, 37.1% less than 10 years. Fifty per cent of respondents worked in urban areas, 19.4% in rural areas and 30.9% in local health units covering both urban and rural areas. Of GPs and paediatricians, 30.5% had fewer than 500 patients, 34.7% between 501 and 1000 patients and 34.7% more than 1000 patients.

A significant difference (p < 0.01) was observed between the percentages of correct answers regarding

Vaccine, Vol. 10, Issue 11, 1992 743

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Immunization: perceived contraindications: C. Zotti et al.

Table 1 Correct answers about each vaccine in presence of 19 contraindications

Vaccine to be given a

Contraindications DT P OPV M

(1) Acute respiratory illness without fever Would Would Would Would (2) Febrile illness Postpone it Postpone it Postpone it Postpone it (3) Asthma Would Would Would Would (4) Eczema Would Would Would Would (5) Allergic to hens' eggs Would Would Would Would (6) Sensitive to neomycin Would Would Would Would not (7) Receiving immunosuppressing treatment Postpone it Postpone it Postpone it Postpone it (8) Receiving oral steroids Postpone it Postpone it Postpone it Postpone it (9) HIV-positive baby Would Would Wouldnot Would not

(10) Diarrhoea Would Would Postpone it Would (11) Chronic diarrhoea Would Would Would not Would (12) Evolving neurological disease Would Would not Would Would (13) Febrile convulsions Would Would not Would Would (14) Neurological deficit Would Postpone it Would Would (15) Epilepsy or family epilepsy Would Would not Would Would (16) Child delivered prematurely Would Would Would Would (17) Chronic lung disease Would Would Would Would (18) Chronic heart disease Would Would Would Would (19) Mother of child is pregnant Would Would Would Would

aDT, Diphtheria-tetanus; P, pertussis; OPV, oral polio vaccine; M, measles

Table 2 Percentage of correct answers in relationship with specialization, experience and number of patients of interviewees

Specialization b ( % )

Vaccine a PED GPs DPVC

Experience (%)

< 20 years

Numbers of patients (%)

>20 years < 1000 > 1000

DT 70.8 64.9 75.4 71.4 P 57.6 52 69.2 59.2 OPV 67 61.9 73.6 67.5 M 58.1 52.2 63.2 57.7

60 69.6 63.8 47.9 56.5 50.8 57.6 65.7 60.5 51.5 55.9 53.5

"DT, Diphtheria-tetanus; P, pertussis; OPV, oral polio vaccine; M, measles. bPED, paediatricians; GPs, general practitioners; DPVC, doctors of Public Vaccination Service

compulsory immunizations and those regarding non- compulsory immunizations (67 and 56.5 %, respectively ).

The distribution of correct answers in relation to specialization shows the highest values in the group of DPVCs, followed by paediatricians and GPs in a decreasing trend (p < 0.01 ) (Table 2). All of the groups interviewed were better informed about DT vaccine than about OPV, and all of them were poorly informed about measles and pertussis immunization.

The frequency of correct answers was significantly higher (p < 0.01 ) in the group with less than 20 years of experience (Table 2). When the number of patients was taken into consideration, the frequency of correct answers in the group with more than 1000 patients was lower ( Table 2).

To evaluate the aossible confounding effect of variables such as specialization, experience and number of patients, multiple logistic analysis was used: the dependent variable 'answer' correct or incorrect) was related to the independent variables 'specialization', 'experience', 'numbers of patients' in a dichotomous form. DPVC specialization was not considered because DPVCs are public health service operators and they have no patients. Regression coefficients showed that correct answers are preferentially given by paediatricians and physicians with less than 20 years of experience. The number of patients was not a factor consistently influencing a correct answer.

Considering one contraindication at a time for each vaccine, the lowest percentages of correct answers ( < 5 0 % ) were for DT at eontraindications (1) and (9),

for OPV at (1), (9), (11) and (12), for measles immunization at (1), (5), (6), (9), (10), (12) and (13), and for pertussis immunization at (1), (9), (13), (14) and (15) (Table 3).

D I S C U S S I O N

For the only general contraindication to all vaccines, acute febrile illness (2), more than 80% of respondents answered correctly. Also for false contraindications such as asthma (3), eczema (4), premature baby (16), chronic lung disease (17), chronic heart disease (18) and mother of child pregnant (19), the respondents generally gave appropriate answers.

The higher frequency of correct answers regarding compulsory vaccinations as opposed to non-compulsory immunizations can be explained by their having been in use for a longer time.

The higher frequency of the correct answers given by DPVCs is explained by daily activity in local health unit vaccination centres and experience acquired. The increasing trend of information from GPs to paedia- tricians is explained by the characteristics of paediatricians' patients (children under 12 years). It is more difficult to explain why GPs and paediatricians know less about pertussis vaccination than about measles vaccination, while DPVCs are better informed about pertussis than about measles. One possibility is that pertussis vaccine (in Diphtheria-Tetanus-Pertussis vaccine) was and is mainly used in public health structures, while measles

744 Vaccine, Vol. 10, Issue 11, 1992

Page 4: Compulsory and non-compulsory immunizations: Contraindications perceived by medical practitioners

Table 3 Percentage of correct answers about DT, OPV, measles and pertussis vaccine

Vaccine a to be given (% correct answers)

Contraindications DT OPV M P

(1) Acute respiratory illness 16.2 14.4 12.2 12.9 without fever

(2) Febrile illness 88.5 89.2 89,2 86.3 (3) Asthma 71.6 71.9 61.9 58.3 (4) Eczema 72.3 66.5 62.2 64.4 (5) Allergic to hens' eggs 73.0 68.3 18.7 60.8 (6) Sensitive to neomycin 59.4 56.5 30.6 51.4 (7) Receiving immunosuppressing 52.9 54.3 51.8 52.2

treatment (8) Receiving oral steroids 66.5 71.6 68.3 66.2 (9) HIV-positive baby 38.5 39.2 38.5 30.6

(10) Diarrhoea 57.6 80.6 47.1 51.8 (11) Chronic diarrhoea 81.7 36.7 74,8 76.3 (12) Evolving neurological disease 57.9 39.1 28.1 58.3 (13) Febrile convulsions 65.8 61.9 45.3 44.2 (14) Neurological deficit 84.9 79.9 71.9 2.9 (15) Epilepsy or family epilepsy 79.1 75.2 55.8 44.2 (16) Child delivered prematurely 61.5 61.5 61.5 55.4 (17) Chronic lung disease 90.3 91.7 85.3 82.7 (18) Chronic heart disease 92.1 91.4 89.2 87.1 (19) Mother of child is pregnant 92.8 85.3 74,6 86.0

aDT, Diphtheria-pertussis; OPV, oral polio vaccine; M, measles; P, pertussis

vaccine is used more frequently by paediatricians or GPs. The correlation between experience and correct

answers shows that the respondents with less than 20 years' experience are better informed; it is likely that medical training is at present more directed towards infectious disease prevention than in the past.

Half of the questions raised doubts in the respondents. The opinions expressed about some contraindications suggest that the brevity of the questions posed and of the answers required may have caused some mis- understanding. A detailed elaboration of individual questions was omitted to keep the questionnaire within a single page, even though it might have clarified some of the questions (particularly (7), (8), (9) and (11 )). For example, live virus vaccine should not be given to individuals receiving long-term immunosuppressive therapy, such as corticosteroids at high doses (e.g. prednisone 2 mg kg- 1 day- 1 for longer than l week), irradiation, antimetabolites and alkylating agents. In this case it is recommended that the vaccination schedule be postponed for at least 3 months after therapy. In the case of corticosteroid therapy for less than 2 weeks, only OPV and measles vaccine are postponed, or OPV is substituted with IPV, while DT and pertussis vaccine can be administered. In questions ( 7 ) and (8), dose and duration of immunosuppressive treatment was not specified; we considered as correct those answers suggesting postpone- ment of all four vaccinations.

In the situation 'HIV-positive baby' (9) the answers were mixed, with a high frequency of doubts ('do not know' from 27 to 29.5%); the DPVCs gave correct answers with the highest frequency. According to WHO guidelines, HIV-positive individuals (asymptomatic or symptomatic) may receive live virus vaccines, because the risk of measles for such children is greater than any vaccine-associated risk. IPV may be given at the discretion of the responsible clinician as an alternative to OPV, particularly in the case of symptomatic

Immunization: perceived contraindications: C. Zotti et al.

individuals. In Italy, until 1990, the trend was not to give live vaccines, assuming that all HIV positives had immunodeficiency (Circolare 14/03/1987, Ministry of Health). The possibility of giving live vaccines in HIV- positive patients is not excluded in more recent Public Health Guidelines. In question (9) the correct answer was to give only DT and pertussis vaccine.

Surprisingly, 28.1% of the respondents answered 'would' for OPV in the presence of chronic diarrhoea (11 ); nevertheless the question did not define exactly the duration of illness. The use of IPV instead of OPV is suggested in cases of diarrhoea, which would require postponement of immunization for 6 months.

Correct answers to (12) and (15) were decided according to WHO guidelines: vaccines containing pertussis antigens should not be given to children with evolving neurological diseases (e.g. uncontrolled epilepsy, infantile spasm, progressive encephalopathy). In the case of neurological deficit (14) the evolution of symptoms should be evaluated and pertussis vaccination postponed. In the presence of neurological illness (contraindications (12), (13), (14) and (15)) paedia- tricians showed little concern about immunization, especially in the case of compulsory vaccines; all three groups of respondents agreed in giving immunization in the case of neurological deficit and family or childhood history of epilepsy. The contraindication (14) (neuro- logical deficit) in the case of pertussis vaccine was answered correctly by only 1.8% of paediatricians and 4.8% of DPVCs; the prevailing answers were 'would' (59%) or 'would not' (24.8%) while WHO advises postponing it, if there is any doubt about the evolution of disease. As the question did not specify the progression of illness, we cannot consider the answers 'would' or 'would not' completely wrong.

Extreme caution was shown in the case of evolving neurological disease (infantile spasm, progressive encephalopathy, uncontrolled epilepsy): 37.4% 'would not' for OPV and 50% for measles vaccine. The answer 'do not know' (mean 12.4% ) shows high uncertainty; it shows also that the respondents do not take into consideration the frequency of measles complications as opposed to the almost complete absence of complications from OPV.

Acute respiratory illness without fever (cold or cough) was treated with caution by all those interviewed (especially GPs) and more than 70% of them said they would postpone the vaccination. This unjustified caution can only cause delay in the vaccination schedule.

The answers to the contraindications (5) and (6) show uncertainty about the manufacture of vaccines and their composition; the sensitivity to neomycin is a contra- indication only for measles vaccine and the allergy to egg proteins is a contraindication for influenza and yellow fever vaccines (their viruses are grown on hens' egg tissues). A high frequency of 'do not know' in the case of sensitivity to neomycin and of 'would not' for measles vaccine in the presence of allergy to egg proteins was given also by DPVCs.

In conclusion, we observed an unexplainable reluc- tance to immunize in the case of respiratory disease without fever, a lack of information about composition of vaccines (mainly non-compulsory vaccines) and doubts about the real contraindications for polio, measles and pertussis vaccines. Even though doctors of public vaccination centres are better informed about vaccines,

Vaccine, Vol. 10, Issue 11, 1992 745

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Immunizat ion: perceived contraindicat ions: C. Zott i et al.

it must be considered that babies are immunized by the local health unit vaccination service generally according to the paediatrician's or general practitioner's advice; the crucial role played by these two groups proves that superficial information can prejudice the correct use of active immunization.

REFERENCES

1 Pugh, E.J. and Hawker, R. Measles immunization: Professional knowledge and intention to vaccinate. Community Med. 1986, 8, 340

2 Wilkinson, J.R, Measles immunization. Contraindications perceived

by General Practitioners in one Health District. Public Health 1986, 100, 144

3 Wilkinson, J.R. Measles immunization. Contraindications as interpreted by Health Visitors and Clinic Nurses, Public Health 1985, 98, 198

4 Salmaso, S. Immunization coverage in Italy. Buff. WHO 1984, 62, 585 5 Zotti, C., Sciacovelli, A., Simolo, D., Maiello, A. and Moiraghi

Ruggenini, A. Epidemiologia della pertosse: indagine nelle scuole materne della citt& di Torino. Bo//./st. Sierot. Milan. 1988, 67(3), 210

6 WHO. Indications and contraindications for vaccines used in EPI. Wkly Epidem. Rec. 1979, 59, 13

7 WHO. EPI Global Advisory Group. Wkly Epidem. Rec. 1987, 62, 5 8 WHO. ICP/EPI 019-2374G, August 1988, annex 5, p. 43 9 WHO. Immunization practice (A Guide for Health Workers who Give

Vaccines). Oxford University Press, Oxford, 1989 10 Italian Ministry of Health. Public Health Guidelines, Ministry of

Health, 1991, Circolare no. 9

746 Vaccine, Vol. 10, Issue 11, 1992