Vaccine programmes and policies.

Management of an effective national vaccine strategy necessitates careful planning. In the face of budgetary constraints and the likely development of many new vaccines over the next few years, a rational choice of which vaccines to use and how best to use them will depend on first class disease surveillance, economic analysis of cost effectiveness and mathematical modelling to ensure optimal vaccine delivery. Effective immunisation programmes require strategic planning that integrates the outputs of these parameters with available health facilities with the least possible disruption. At the present time, the greatest threat to vaccination is resistance to continuing vaccination in the face of declining prevalence of many infectious diseases and heightened fears over vaccine safety. Re-assurance of the public that vaccines are safe demands effective detection of vaccine-related side-effects and rigorous investigation of any safety concerns.

The Introduction of Group C Conjugate Meningococcal Vaccine into the UK.

Throughout the 1990s, the incidence of meningococcal disease was higher in England and Wales than in most other European countries (1). In addition to the high incidence, the pattern of disease changed, with shifts to more cases caused by serogroup C strains, and more cases occurring in older teenagers, among whom the case fatality rate is higher than in any other age group (2,3). Not surprisingly, market research undertaken by the UK Health Education Authority consistently showed that meningococcal disease is the most feared disease by parents of young children (unpublished reports based on British Market Research Bureau surveys). By 1999, serogroup C accounted for 41% of laboratory confirmed cases; 49% were serogroup B (3).

The introduction of Haemophilus influenzae type b immunization into the United Kingdom: practical steps to assure success.

Haemophilus influenzae type b (Hib) vaccine was introduced into the routine childhood immunization program in the UK in October, 1992. The implementation was coordinated on a national basis, taking account of market research of the information needs of both the public and health professionals. Vaccine distribution arrangements were linked to the scheduling of children for immunization, which was implemented through a national computerized system of calling children for immunization. All children commencing immunization were called for three doses of Hib vaccine. Children < 1 year of age were called back for three doses of vaccine; children >1 but <4 years were called for one dose. No boosters were given. National coverage from the outset of the campaign exceeded 90%; it is now 95% and the incidence of invasive Hib infection has declined by >95%. Some of the lessons learned from the UK introduction may be of relevance to other countries presently considering the implementation of Hib immunization into their routine immunization programs.

Polio eradication: surveillance implications for the United Kingdom.

The requirements for certification of elimination of wild virus poliomyelitis will pose particular problems for some industrialized countries, such as the United Kingdom, where there has been no case detected for at least a decade. Systems of surveillance of poliomyelitis have been reviewed and potential weaknesses identified. When oral polio vaccine is routinely used, the rate of vaccine-associated cases provides an indication of the likelihood that if they occurred, wild virus cases would be detected. Acute flaccid paralysis surveillance was done for 3 years, but rates were lower than reported elsewhere and were accepted for certification purposes. Alternative techniques, such as surveillance of polioviruses, either in clinical samples or from the environment, may be developed in such countries. The ability to identify enteroviruses and to distinguish between wild and vaccine strains of polioviruses will give assurance that silent transmission of wild viruses is unlikely.

The effect of rings on microbial load of health care workers' hands.

BACKGROUND: The hands of health care workers (HCWs) serve as a major route for transmission of nosocomial infection. Although handwashing is known to reduce cross-transmission of infection, the influence of rings on the efficacy of handwashing and the carriage of bacteria on the hands has not been well established. METHODS: In this study, 50 HCWs with rings were paired by unit with 50 HCWs without rings. Cultures were obtained by use of a timed-friction rinse before and after a timed handwashing. Standard laboratory procedures were followed for identification of the bacteria. RESULT: When colony counts before handwashing are taken into consideration, a significant difference is seen after handwashing between the two groups (R2 = 0.56). The regression model showed that the slope was significantly steeper (p < 0.0014) for the group with rings. This effect is more apparent when the colony count on hands is greater than 1000 colony forming units before handwashing. CONCLUSIONS: A standardized, timed handwashing procedure was effective in decreasing the bioload of HCWs' hands. The effect of rings on the bioload was significant in this study.

Measles vaccination and Guillain-Barré syndrome.

BACKGROUND: Guillain-Barré syndrome (GBS) has been associated with several infectious agents, and the possibility that the disorder may be caused by vaccination has been raised. We compared the numbers of cases of GBS observed immediately after mass measles vaccination campaigns with the numbers that would be expected from baseline rates, to assess whether there is a causal relation between measles vaccination and GBS. METHODS: We analysed data on 2296 cases of GBS reported to the Poliomyelitis Eradication Surveillance System of the Pan American Health Organization as cases of suspected poliomyelitis. These cases occurred among 73 million immunised children aged 9 months to 15 years in Argentina, Brazil, Chile, and Colombia, between January, 1990, and December, 1994. These children were targeted for mass measles vaccination campaigns (each lasting 1 month) in 1992 and 1993. The frequency of GBS cases observed during the vaccination campaigns or the next 42 days (the latent period) was compared with that during the rest of the study period, with the assumption of a Poisson distribution. FINDINGS: The average annual incidence of GBS was 0.62 per 100000 children aged 1-14 years. The number of cases that would be expected within any 72-day period would therefore be 92. The average observed number of cases during latent periods after measles vaccination was 97. The probability that 97 or more cases would occur during a period with an expected number of 92 was 0.31. INTERPRETATION: The average annual rates of GBS by age-group for the 5 years analysed were consistent with previous data; thus we are confident that the surveillance system is sufficiently sensitive. There was no statistically significant association between measles vaccination and GBS. If there is any causal relation, the number of GBS cases due to measles vaccination was so small that data from the vaccination of more than 70 million children were not sufficient to detect a rise in the number of observed GBS cases beyond the expected number.

Surveillance of poliomyelitis in the United Kingdom.

Routine surveillance of poliomyelitis is undertaken through statutory notification, laboratory reporting, and examination of death certificates where poliomyelitis is mentioned. All health districts report weekly and include zero reporting of poliomyelitis in their returns. UK weekly reports on poliomyelitis are forwarded to WHO Europe. There have been no wild virus cases for over a decade. Since August 1991, there has been active surveillance of acute flaccid paralysis (AFP) in children under 16 years. All Consultant Paediatricians are contacted monthly through the British Paediatric Surveillance Unit and asked for reports of any cases of AFP. These are then investigated further. The study protocol specifies the investigations that are required for AFP cases, including stool samples for virology. AFP rates from this surveillance, approximately one per hundred thousand children under 16 years, provide a valuable guide for industrialised countries; consideration is being given to extending this scheme into the adult population. In 1992, a 44-year-old man died after sudden onset of AFP. Histology suggested poliomyelitis, and intensive investigations were undertaken to establish a diagnosis. The role of AFP surveillance and investigation of suspected cases are discussed in the light of the need to establish that poliomyelitis has been eliminated.

Brain revascularisation in hypertension.

Neurological symptoms in hypertensive subjects may be a reflection of intracranial vascular disease and not just a consequence of hypertension. Two hypertensive children with renovascular disease, neurological symptoms, and severe cerebral arterial disease were treated by extracranial-intracranial arterial bypass surgery with improvement of symptoms and easier control of blood pressure. Where revascularisation surgery is appropriate, this should be undertaken before neurological complications arise.