Benefits and risks of pertussis vaccine

Respiratory sequelae of whooping cough. Swansea Research Unit of the Royal College of General Practitioners

Eight hundred and thirteen children who had had whooping cough when under 5 years of age in the 1977-9 epidemic were compared with a control group roughly four and a half years later, each child being matched by age and sex and from the same class in school. The index group showed long term respiratory sequelae of whooping cough--namely, deterioration in lung function, increase in respiratory symptoms, and increased admission to hospital for both upper and lower respiratory conditions. Asthma was significantly more common in the index group, suggesting that asthma was being regarded as a contraindication to pertussis vaccination. Only 3.5% of the asthmatic children in the index group had been vaccinated as against 29.1% of the controls.

Screening for Down's syndrome using serum alpha fetoprotein: a retrospective study indicating caution

A report was made on the outcome of a four year retrospective study in 27 064 pregnancies, of the clinical efficiency, sensitivity, and specificity of a screening programme for Down's syndrome based on reported strategies related to the measurement of maternal serum alpha fetoprotein. This study identified 27 pregnancies affected by Down's syndrome with a median multiple of the median maternal serum alpha fetoprotein concentration of 0.82. This figure is considerably higher than that obtained from previous reports on this subject. With an age related multiple of the median maternal serum alpha fetoprotein strategy, 30.8% of Down's affected pregnancies were identified as well as 11.6% of unaffected pregnancies. Perhaps a United Kingdom collaborative study should begin to investigate the reasons for such wide population variance in the reports for the median multiple of the median for Down's affected pregnancies. Until such studies are carried out, screening for Down's syndrome based on low maternal serum alpha fetoprotein concentration is premature.

Pertussis: herd immunity and vaccination coverage in St Lucia

In a single complete epidemic in St Lucia, an island too small to support constant clinical pertussis, the pertussis case rates in small communities (villages and small towns) with differing levels of vaccination coverage of young children were compared. The association between greater vaccination coverage and greater herd immunity was clear, despite the imperfect protection given to individuals. An analysis in terms of population dynamics is evidence against the theory that endemic subclinical pertussis maintains transmission in a highly vaccinated population. We suggest that with a homogeneous vaccination coverage of 80% of 2-year-old children pertussis might be eradicated from the island, and that this is a practicable experiment.

Pertussis: should we immunise neurologically disabled and developmentally delayed children?

A total of 400 children with neurological disorders were studied to ascertain whether they had been immunised against pertussis, the reasons for non-immunisation, and the "validity" of these reasons, as judged by interpretation of the recommendations of the Department of Health and Social Security. The results for this group were compared with those for a group of 400 aged matched controls. The study group had a significantly lower rate of immunisation than controls (p less than 0.01); rates for both groups fell sharply after 1975. A total of 192 study patients and 186 controls were not immunised. Those children with cerebral palsy had the lowest rate of immunisation (19%) and the highest number of valid reasons for non-immunisation (63%). Paediatricians apparently advised against immunisation in 61 (32%) of the index group but in only four (2%) of the controls. The risk of serious neurological handicap after pertussis immunisation is small and there is little evidence to support the view that underlying neurological disease predisposes a child to increased risk. The advice currently given by paediatricians may need to be reconsidered.