Carrier priming to improve pneumococcal disease control and reduce the international program's cost in children.

Pneumococcal conjugate vaccine (PCV) has the potential to interact with other vaccines containing diphtheria toxin-like antigens (such as those found in the DTP vaccine) upon sequential administration. This is attributed to the similarity of the diphtheria toxoid antigen to the carrier protein used to make PCV, (known as cross reactive material [CRM]) to diphtheria toxin 197 or CRM197. The interaction could lead to enhanced immunogenicity of PCV as a result of a phenomenon called carrier priming, whereby DTP is given some weeks before the first dose of PCV. This phenomenon could be implemented in the immunisation schedule in developing countries and among vulnerable populations to enhance the immunogenicity of PCV, reduce the number of doses required, and produce a more cost-effective immunisation program in developing countries

Use of Vaccine Trials to Estimate Burden of Disease

Vaccine trials, the most informative way of determining the efficacy of a vaccine, can also provide valuable information about the burden of disease. The burden of Haemophilus influenzae type b (Hib)remains a major barrier to the use of Hib vaccines, especially in Asia. Recent studies in Indonesia and Bangladesh have used vaccine-trial designs, with known effective vaccines, to estimate the vaccinepreventable burden of Hib disease in those communities. New vaccines against pneumonia and diarrhoeal diseases are usually directed at only one of various causes of the syndrome. In the case of pneumonia, it is very difficult to determine the aetiology in most cases, so the vaccine trial offers a means of determining the burden of vaccine-preventable diseases. This is particularly important for pneumococcal vaccines as serotype replacement may reduce the effectiveness of the vaccines in the field. This approach would underestimate disease burden if vaccines were found to have an impact on syndromes other than those against which they are directed, and might lead to errors in estimation if there were erroneous assumptions about the efficacy of the vaccine against the condition under investigation

Beyond good intentions: lessons on equipment donation from an African hospital.

OBJECTIVE: In 2000, a referral hospital in the Gambia accepted a donation of oxygen concentrators to help maintain oxygen supplies. The concentrators broke down and were put into storage. A case study was done to find the reasons for the problem and to draw lessons to help improve both oxygen supplies and the success of future equipment donations. METHODS: A technical assessment of the concentrators was carried out by a biomedical engineer with relevant expertise. Semi-structured interviews were undertaken with key informants, and content analysis and inductive approaches were applied to construct the history of the episode and the reasons for the failure. FINDINGS: Interviews confirmed the importance of technical problems with the equipment. They also revealed that the donation process was flawed, and that the hospital did not have the expertise to assess or maintain the equipment. Technical assessment showed that all units had the wrong voltage and frequency, leading to overheating and breakdown. Subsequently a hospital donations committee was established to oversee the donations process. On-site biomedical engineering expertise was arranged with a nongovernmental organization (NGO) partner. CONCLUSION: Appropriate donations of medical equipment, including oxygen concentrators, can be of benefit to hospitals in resource-poor settings, but recipients and donors need to actively manage donations to ensure that the donations are beneficial. Success requires planning, technical expertise and local participation. Partners with relevant skills and resources may also be needed. In 2002, WHO produced guidelines for medical equipment donations, which address problems that might be encountered. These guidelines should be publicized and used