- Email: [email protected]
MYTHICAL CONTRAINDICATIONS TO VACCINATION
994
provided is 0’636-0-810—ie, the true somewhere in that interval. All probably proportion (sensitivity) these proportions (or odds) are vulnerable to this uncertainty and the results of calculations based on them are correspondingly uncertain. For instance, the predictive value of positive test (PV +) in Simel’s fig 2 is 0-89, the true PV + could be as low as 0-76, if chance were turning up the worst estimates. PV- is similarly interval for the estimate
is
vulnerable to estimation variation. Dr Mdller-Petersen (p 348) also uses proportions estimated from clinical samples. His nomogram requires for its operation an estimated proportion and a "likelihood ratio", which is the ratio of two proportions and thus is subject to two doses of sampling variation. All three communications contain well-established bayesian logic and accurate arithmetic but none mention the sample variation that attends all attempts to estimate, from clinical observations, disease prevalence, test sensitivity and specificity, predictive values, and so on. I do not share Balla’s view that valid estimates are "generally available". The prevalence and symptoms of many common diseases are changing all the time. For instance, what is the prevalence of positive streptococcal throat cultures, in this laboratory, among these children, in this month, in a particular community? What proportion of children with positive throat cultures have fever, headache, cough, or rash? These proportions are constantly changing and they vary across communities, seasons demographic conditions (family size), and so on. The use of precise and unqualified proportions (probabilities) makes the bayesian calculations look scientific, but the nuts and bolts that go into them are not that dependable. Los Lunas Hospital and Training School, Los Lunas, New Mexico 87031, USA
GEORGE W. BROWN
MYTHICAL CONTRAINDICATIONS TO VACCINATION
SIR,-Dr Nicoll (March 23, p 679) proposed that mythical contraindications, perpetuated by both parents and providers, are a
major cause of poor vaccine uptake. We would like to provide some figures to support this view. We assessed the frequency of failure of vaccine uptake and reasons for this in 96 children aged between 18 and 35 months attending Sydenham Children’s Hospital during two weeks of February, 1985. Reasons for failure of vaccine uptake could be classified as "parental choice" or "on medical advice", in accordance with current Department of Health and Social Security guidelines. The frequency of "mythical" reasons given by both parents and providers is high (table). FREQUENCY
OF AND REASONS FOR FAILURE OF VACCINE UPTAKE IN
96 CHILDREN
22 parents of the 54 children who had not received one or more vaccines were prepared to complete the programme. 21 would have agreed to start the programme while the child was in hospital, had a service been available. Paediatricians can thus take advantage of having a captive hospital population to help their community colleagues to contend with the problem of failure to take up immunisation. Department of Paediatrics, Guy’s Hospital, London SE1 9RT
ALISON WALKER LESLEY REES
Commentary from Westminster The Government Acts to Prohibit Surrogacy
Arrangements THE Government has set out its
reasons
in detail for
legislating quickly to outlaw commercial surrogacy in Britain. The Surrogacy Arrangements Bill, having had its Second Reading in the Commons, will be law before the summer recess.
The Social Services Secretary, Mr Norman Fowler, in the debate that the Bill did not set out to deal with all the issues raised by the Warnock Report, which would be the subject of comprehensive legislation to be introduced at a later stage to Parliament. But the Government felt a need to act quickly against surrogacy for money because of public concern expressed following the "Baby Cotton" case last January. Consultations after the Warnock report’s publication showed that 90% of organisations and individuals who responded were in favour of prohibiting commercial surrogacy, including churches, women’s organisations, and professional bodies such as the Royal College of Gynaecologists and Obstetricians, the Royal College of General Practitioners, and the Royal College of Nursing. All agreed that the presence of commercial agencies in surrogacy arrangements would lead to the exploitation of women. "Frankly," Mr Fowler commented, "I believe that it is simply unacceptable to sell children, whether before or after birth." On the other hand, it would be wrong, he said, to prosecute a woman who offered herself as a surrogate mother, because of the possibility of passing on the taint of criminality to the child, and because it was just as likely that the woman herselfwould be exploited. If the Government had postponed legislating on surrogacy until the rest of its proposals on the many other issues arising from Warnock were ready, Mr Fowler added, there would be more births to surrogate mothers which would take place "in a legal limbo". There could be cases in which a baby, born deformed, say, was disowned by all involved, and an early Bill would prevent this. The Government proposals forbid the advertising of surrogacy services by agencies, surrogate mothers, or commissioning parents. Initiating or taking part in negotiations towards surrogacy, or compiling information with a view to doing so, were also forbidden by the Bill. If an organisation were to receive payment for a surrogacy arrangement, or a person were to take part in the management and control of a commercial surrogacy arrangement, an offence would have been committed in both cases. Commercial agency activities will carry a fine of up to 2000 or three months’ imprisonment, or both. Advertising will carry only a fine of up to 2000. The permission of the Director of Public Prosecutions will be needed before proceedings are taken. The Government did not want to penalise the infertile couple who might be driven by their plight to making a surrogacy arrangement, nor was there a wish to penalise a surrogate mother who genuinely considers herself to be helping another woman unable to carry a child, Mr Fowler stated. The major commercial surrogacy agency which had been operating in Britain had now stopped operations here. Local authorities would soon receive official guidelines on what to do if an infant were born within their jurisdiction as a result of a surrogacy arrangement, since the Government realised that there were several such pregnancies still in train. "An authority that knows that a
explained
provided is 0’636-0-810—ie, the true somewhere in that interval. All probably proportion (sensitivity) these proportions (or odds) are vulnerable to this uncertainty and the results of calculations based on them are correspondingly uncertain. For instance, the predictive value of positive test (PV +) in Simel’s fig 2 is 0-89, the true PV + could be as low as 0-76, if chance were turning up the worst estimates. PV- is similarly interval for the estimate
is
vulnerable to estimation variation. Dr Mdller-Petersen (p 348) also uses proportions estimated from clinical samples. His nomogram requires for its operation an estimated proportion and a "likelihood ratio", which is the ratio of two proportions and thus is subject to two doses of sampling variation. All three communications contain well-established bayesian logic and accurate arithmetic but none mention the sample variation that attends all attempts to estimate, from clinical observations, disease prevalence, test sensitivity and specificity, predictive values, and so on. I do not share Balla’s view that valid estimates are "generally available". The prevalence and symptoms of many common diseases are changing all the time. For instance, what is the prevalence of positive streptococcal throat cultures, in this laboratory, among these children, in this month, in a particular community? What proportion of children with positive throat cultures have fever, headache, cough, or rash? These proportions are constantly changing and they vary across communities, seasons demographic conditions (family size), and so on. The use of precise and unqualified proportions (probabilities) makes the bayesian calculations look scientific, but the nuts and bolts that go into them are not that dependable. Los Lunas Hospital and Training School, Los Lunas, New Mexico 87031, USA
GEORGE W. BROWN
MYTHICAL CONTRAINDICATIONS TO VACCINATION
SIR,-Dr Nicoll (March 23, p 679) proposed that mythical contraindications, perpetuated by both parents and providers, are a
major cause of poor vaccine uptake. We would like to provide some figures to support this view. We assessed the frequency of failure of vaccine uptake and reasons for this in 96 children aged between 18 and 35 months attending Sydenham Children’s Hospital during two weeks of February, 1985. Reasons for failure of vaccine uptake could be classified as "parental choice" or "on medical advice", in accordance with current Department of Health and Social Security guidelines. The frequency of "mythical" reasons given by both parents and providers is high (table). FREQUENCY
OF AND REASONS FOR FAILURE OF VACCINE UPTAKE IN
96 CHILDREN
22 parents of the 54 children who had not received one or more vaccines were prepared to complete the programme. 21 would have agreed to start the programme while the child was in hospital, had a service been available. Paediatricians can thus take advantage of having a captive hospital population to help their community colleagues to contend with the problem of failure to take up immunisation. Department of Paediatrics, Guy’s Hospital, London SE1 9RT
ALISON WALKER LESLEY REES
Commentary from Westminster The Government Acts to Prohibit Surrogacy
Arrangements THE Government has set out its
reasons
in detail for
legislating quickly to outlaw commercial surrogacy in Britain. The Surrogacy Arrangements Bill, having had its Second Reading in the Commons, will be law before the summer recess.
The Social Services Secretary, Mr Norman Fowler, in the debate that the Bill did not set out to deal with all the issues raised by the Warnock Report, which would be the subject of comprehensive legislation to be introduced at a later stage to Parliament. But the Government felt a need to act quickly against surrogacy for money because of public concern expressed following the "Baby Cotton" case last January. Consultations after the Warnock report’s publication showed that 90% of organisations and individuals who responded were in favour of prohibiting commercial surrogacy, including churches, women’s organisations, and professional bodies such as the Royal College of Gynaecologists and Obstetricians, the Royal College of General Practitioners, and the Royal College of Nursing. All agreed that the presence of commercial agencies in surrogacy arrangements would lead to the exploitation of women. "Frankly," Mr Fowler commented, "I believe that it is simply unacceptable to sell children, whether before or after birth." On the other hand, it would be wrong, he said, to prosecute a woman who offered herself as a surrogate mother, because of the possibility of passing on the taint of criminality to the child, and because it was just as likely that the woman herselfwould be exploited. If the Government had postponed legislating on surrogacy until the rest of its proposals on the many other issues arising from Warnock were ready, Mr Fowler added, there would be more births to surrogate mothers which would take place "in a legal limbo". There could be cases in which a baby, born deformed, say, was disowned by all involved, and an early Bill would prevent this. The Government proposals forbid the advertising of surrogacy services by agencies, surrogate mothers, or commissioning parents. Initiating or taking part in negotiations towards surrogacy, or compiling information with a view to doing so, were also forbidden by the Bill. If an organisation were to receive payment for a surrogacy arrangement, or a person were to take part in the management and control of a commercial surrogacy arrangement, an offence would have been committed in both cases. Commercial agency activities will carry a fine of up to 2000 or three months’ imprisonment, or both. Advertising will carry only a fine of up to 2000. The permission of the Director of Public Prosecutions will be needed before proceedings are taken. The Government did not want to penalise the infertile couple who might be driven by their plight to making a surrogacy arrangement, nor was there a wish to penalise a surrogate mother who genuinely considers herself to be helping another woman unable to carry a child, Mr Fowler stated. The major commercial surrogacy agency which had been operating in Britain had now stopped operations here. Local authorities would soon receive official guidelines on what to do if an infant were born within their jurisdiction as a result of a surrogacy arrangement, since the Government realised that there were several such pregnancies still in train. "An authority that knows that a
explained