Immunization standards

Recall and destruction of specific batches of yellow fever vaccine from Institut Pasteur, Dakar


15 December 2010

Following completion of a vaccine quality investigation which took place from August to November 2010, WHO recommends that, as a precautionary measure, lots 2148 (20-dose ampoules, expiration September 2012) and 2159 (20-dose ampoules, expiration October 2012) of yellow fever vaccine, Vaccin Amaril Stabilisé, produced by Institut Pasteur, Dakar, Senegal be recalled and destroyed by the manufacturer (50 000 ampoules total for both lots). From the quality perspective, since vaccine from the affected lots can be expected to have induced satisfactory immunity, there is no need for revaccination of persons who have already been administered vaccine from these lots. Corrective action has been implemented by the manufacturer, and thus the vaccine remains on the list of WHO prequalified vaccines.

Background

On 6 August 2010, WHO recommended the temporary suspension of the distribution and use of lots 2148 and 2149 of the yellow fever vaccine produced by Institut Pasteur, Dakar, due to the presence, in some ampoules, of dark brown material which was sticking to the neck of the glass ampoule. This action was taken as a precautionary measure pending investigation of vaccine quality complaints from the Central African Republic and Côte d'Ivoire, received by WHO on 29 July 2010.

The manufacturer conducted an investigation to determine the root cause of the defect. The national regulatory authority of Senegal also conducted an on-site inspection to investigate the root cause of the defect and potential implications for other batches of the vaccine. WHO checked whether any reports of adverse events following immunization (AEFI) with this vaccine had been received.

The investigation conducted by the manufacturer concluded that the residue found in ampoules of lots 2148 and 2159 resulted from a sealing problem. The inspection report by the national regulatory authority of Senegal concurred with this finding. These conclusions were supported by independent testing commissioned by WHO. No adverse events following immunization with Amaril have been reported to WHO.

Corrective action in the form of revalidation of the sealing process has been implemented by the manufacturer, and preventive action in the form of establishing acceptance limits for rejection due to appearance is being taken, to ensure compliance with good manufacturing practices.

In view of the rapid response by the manufacturer and regulatory authority to identify the root cause, and the introduction of simple corrective measures, WHO considers that the risk-benefit ratio for future batches of this product remains favorable, and so the product remains on the list of WHO prequalified vaccines.

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