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Papua New Guinea has been providing expanded immunization services for more than 14 years. While immunization coverage has risen dramatically, recent surveys have raised serious questions regarding vaccine potency at the service delivery level. Operational practices in vaccine distribution and in the delivery system have been identified in this paper. The international and national standards for vaccine management are described along with the main requirements for maintaining vaccine potency. Quality assurance measures, the responsible personnel and the appropriate intervention points are detailed, along with easily applied guidelines for implementation. An approach to assessing the effectiveness of the quality assurance measures is proposed.

PIP: Although Papua New Guinea agreed to reach 90% immunization of children under one year of age, this country and 5 others were unable to reach the coverage target. A survey of facilities was conducted, and analysis revealed serious systems failures and operational problems. Consequently, large numbers of children were receiving ineffective vaccines. When immunization coverage is low, disease is transmitted to those without coverage. For example, a failure of a single dose of the diphtheria-pertussis-tetanus (DPT) or oral polio vaccine results in only partial protection and the ability to transmit the diseases purportedly covered. There is great waste of effort and work, money, health worker time, facilities use, and equipment and vaccines, when inadequate coverage is achieved. Improvements are needed in assuring vaccine potency, adequate distribution, maintenance of the cold chain, and transportation of vaccine supplies. The causes of vaccine damage include the distribution chain of international supplies, vaccine temperatures by type of vaccine, vaccine conditions, vaccine storage conditions, storage risk factors, kerosene refrigerator conditions, sanitary immunization practices, and quality assurance points in the distribution chain. There were situations where boxes were supposed to be lined with frozen ice packs, but there were inadequate numbers of ice packs; road transport time with packs should be 1 day or less, when in fact it took 1-2 days, and air shipments could take a week. Placement in refrigerators may mean warming on one shelf and freezing on another shelf. When mobile teams transported vaccines to rural areas, the carrying boxes were insufficiently packed for transport longer than 1 day. Recommended measures were procurement of appropriate vaccines and equipment, development of guidelines, instructions and supervision, and provision of training. Area medical stores need to perform quality assurance when vaccines arrive, are being unpacked, or are in storage before shipment to another location.

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From January, 1988, to March, 1989, a widespread outbreak (118 cases) of poliomyelitis type 1 occurred in Oman. Incidence of paralytic disease was highest in children younger than 2 years (87/100,000) despite an immunisation programme that recently had raised coverage with 3 doses of oral poliovirus vaccine (OPV) among 12-month-old children from 67% to 87%. We did a case-control study (70 case-patients, 692 age-matched controls) to estimate the clinical efficacy of OPV, assessed the immunogenicity of OPV and extent of poliovirus spread by serology, retrospectively evaluated the cold chain and vaccine potency, and sought the origin of the outbreak strain by genomic sequencing. 3 doses of OPV reduced the risk of paralysis by 91%; vaccine failures could not be explained by failures in the cold chain nor on suboptimum vaccine potency. Cases and controls had virtually identical type 1 neutralising antibody profiles, suggesting that poliovirus type 1 circulation was widespread. Genomic sequencing indicated that the outbreak strain had been recently imported from South Asia and was distinguishable from isolates indigenous to the Middle East. Accumulation of enough children to sustain the outbreak seems to have been due to previous success of the immunisation programme in reducing spread of endemic strains, suboptimum efficacy of OPV, and delay in completing the primary immunisation series until 7 months of age. Additionally, the estimated attack rate of infection among children aged 9-23 months exceeded 25% in some regions, suggesting that a substantial proportion of fully vaccinated children had been involved in the chain of transmission.

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A case of solitary spinal hemangioblastoma with spontaneous subarachnoid hemorrhage is presented. There was no features to distinguish the subarachnoid hemorrhage in this case from that due to an intracranial lesion. However, mild sensory symptoms involving the left arm and leg had preceded the hemorrhage by several months. The lesion was detected by cerebral angiography and computed tomographic scanning, and the diagnosis was confirmed at operation. A small syrinx was noted, and the lesion was totally removed without causing any deficit, despite its origin from the dorsum of the spinal cord. The tumor contained a false aneurysm, which had been visualized angiographically.

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