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N Dellepiane

Publications and source records attributed to N Dellepiane.

9 recordsLinked to original sources
PubMed2001

Laboratory testing of whole cell pertussis vaccine: a WHO proficiency study using the Kendrick test.

Whole cell pertussis vaccine (WCV), commonly in combination with vaccines for diphtheria and tetanus, has an important role in reducing morbidity and mortality among children in most parts of the world. Testing to assure the efficacy of such vaccines is essential. We have, therefore, carried out, under the Global Training Network (GTN) of the Department of Vaccines and Biologicals at the World Health Organization (WHO), a proficiency study involving 13 laboratories in 12 countries that routinely test WCV. Two vaccine samples were tested in this study and represented samples which were expected clearly either to pass (sample B, a full strength vaccine) or to fail (sample A, 1/8 strength of vaccine B). Data from this study showed good performance by the majority of participants. Most assays were statistically valid and were carried out to the level of precision achieved for these assays in previous studies. This study also indicated that, relative to the assay precision, the in-house reference (IHR) preparations are in general accurately calibrated. Statistically valid assays of the sub-potent vaccine, A, showed it to fail in all except one laboratory. Statistically valid assays of the potent vaccine, B, showed it to pass in all laboratories. Nevertheless, the between laboratory variability of estimates for vaccine B, and for comparisons of the two vaccine samples suggested that there are some differences in results in different laboratories. The introduction of a common working standard may assist in reducing inter-laboratory variation. This study has shown clearly satisfactory performance by most laboratories. However, a serious problem was detected in one laboratory where the sub-potent vaccine A could have been passed and was not distinguished from the eight-fold more potent vaccine B. There were also indications of possible problems in several other laboratories, where IHR preparation may not be accurately calibrated or where vaccine samples A and B may not be completely distinguished. Although this study provides reassurance that most laboratories perform well, it demonstrates the essential role of ongoing proficiency studies in high-lighting problems.

Animals↗
PubMed2001

Mass psychogenic illness following tetanus-diphtheria toxoid vaccination in Jordan.

In September 1998, more than 800 young people in Jordan believed they had suffered from the side-effects of tetanus-diphtheria toxoid vaccine administered at school; 122 of them were admitted to hospital. For the vast majority, their symptoms did not result from the vaccine but arose from mass psychogenic illness. The role played by the media, the children's parents, and the medical profession in the escalation of this mass reaction appeared, at first sight, to be unusual and even unique to the circumstances in Jordan at the time. A review of the literature showed, however, that this mass reaction was similar in many ways to previous outbreaks, even though the underlying causes varied. There are about 200 published accounts of mass responses to situations involving suspected poisoning or other events. Because such mass reactions are relatively rare and the triggers so diverse, individuals faced with responding to them are unlikely to have prior experience in how to handle them and are unlikely to take bold steps to prevent their escalation. Indeed they may be unaware that such events have been recorded before. The lessons learned from this incident in Jordan may help other immunization programme managers to handle crisis situations elsewhere.

Adolescent↗
PubMed2000

New challenges in assuring vaccine quality.

In the past, quality control of vaccines depended on use of a variety of testing methods to ensure that the products were safe and potent. These methods were developed for vaccines whose safety and efficacy were based on several years worth of data. However, as vaccine production technologies have developed, so have the testing technologies. Tests are now able to detect potential hazards with a sensitivity not possible a few years ago, and an increasing array of physicochemical methods allows a much better characterization of the product. In addition to sophisticated tests, vaccine regulation entails a number of other procedures to ensure safety. These include characterization of starting materials by supplier audits, cell banking, seed lot systems, compliance with the principles of good manufacturing practices, independent release of vaccines on a lot-by-lot basis by national regulatory authorities, and enhanced pre- and post-marketing surveillance for possible adverse events following immunization. These procedures help assure vaccine efficacy and safety, and some examples are given in this article. However, some contaminants of vaccines that can be detected by newer assays raise theoretical safety concerns but their presence may be less hazardous than not giving the vaccines. Thus risk-benefit decisions must be well informed and based on scientific evidence.

Humans↗
PubMed1999

Alternatives and developing countries.

Alternative tests have a role in vaccine testing, especially to confirm production consistency. Given the characteristics of these alternative tests and of the products for which they may be used, there are several factors which will influence their use. These include a good understanding of the test and the product to be tested, strong national regulatory infrastructure, a laboratory run in accordance with the principles of laboratory quality systems, and the ability to validate the alternative method. This means that national regulatory authorities will need strong expertise in epidemiology and quality assurance to complement laboratory experience.

Animal Testing Alternatives↗
PubMed1999

Availability of quality fixed-dose combinations for the treatment of tuberculosis: what can we learn from studying the World Health Organization's vaccine model?

SETTING: In efforts to promote the use of fixed-dose combinations (FDCs) for the treatment of tuberculosis (TB), the World Health Organization (WHO) and partners address the issue of quality assurance. OBJECTIVE: To provide guidance for the development of strategies for quality assurance of FDCs. DESIGN: This review examines the WHO strategies for and experience with quality assurance and supply of vaccines. RESULTS: Several elements in the strategies for quality assurance and supply of vaccines may be applicable for FDCs. At national level, the important strategies are to strengthen National Regulatory Authorities (NRA) and procurement systems and develop planning activities. Stressing quality assurance of FDCs in training activities for regulatory personnel and recommending that aid agencies require adherence to quality assurance policies as conditions for support would promote the implementation of quality assurance of FDCs at country level. At the global level, pre-qualification of manufacturers of FDCs should be explored as a mechanism to assure quality. The pre-qualification process should include evaluation of product files, initial testing for compliance and consistency of specifications, and site visits to producers and NRAs. The vaccine model defines criteria for reassessment that can be used for FDCs.

Antitubercular Agents↗
PubMed1990

Rabies reference vaccine for use as a regional standard for Latin America and the Caribbean countries.

A candidate rabies reference vaccine of suckling mouse brain (SMB) origin was prepared and standardized at the Pan American Zoonoses Center (PAHO/WHO) and evaluated in a collaborative study involving seven laboratories. On the basis of three different tests, its potency, immunogenicity, and stability were demonstrated to be satisfactory. The vaccine was proposed for consideration of the Latin American and Caribbean countries as a regional standard to determine the potency of SMB vaccines, the most widely used in the Region.

Animals↗
PubMed1989

[Antirabies vaccine from the brain of the suckling rat: antigen composition and immunogenic capacity].

Suckling mouse brain (SMB) rabies vaccine is the preparation most widely used in the countries of Latin American and the Caribbean. This vaccine, prepared according to the Fuenzalida and Palacios method, consists of three fixed rabies virus strains (CVS, 51, and 91). However, the World Health Organization recommends that rabies vaccines for human use be prepared using only a single strain of this virus. In order to determine whether any one of the antigens of the SMB vaccine could be eliminated from the preparation, the immunogenic capacity of the standard trivalent SMB vaccine was compared with that of experimental bivalent (CVS-51, CVS-91, and 51-91) and monovalent (CVS, 51, and 91) SMB vaccines. The study was conducted using adult and suckling albino mice provided by the laboratory at the Pan American Zoonoses Center, Buenos Aires, Argentina, and different strains of fixed and street rabies virus. The experimental vaccines were prepared using the Fuenzalida-Palacios method. Potency and cross-immunity tests were conducted. The results showed that the trivalent vaccine was the most effective in protecting the mice against both fixed and street rabies virus infections and also in inducing rapid development of neutralizing antibody at high titers.

Animals↗