Following a routine site audit conducted by a WHO team of the vaccine manufacturer, Panacea Biotec  and the conclusions of an adhoc committee convened by WHO, the following diphtheria-pertussis-tetanus-based combination vaccines: Easyfive (DTwP-Hep B-Hib), Ecovac4 (DTwP-Hep B), and EnivacHB (Hepatitis B); have been removed from the list of vaccines prequalified by WHO.

During the site audit, which took place from 27 June-1 July at the Lalru manufacturing site, it became clear to the WHO team that Panacea's quality systems on this site do not meet the requirements for WHO prequalification.

Specifically, deficiencies in the quality management system found at the Lalru site relate to the manufacture of the haemophilus influenzae type b (Hib) and hepatitis B bulks used for the formulation of the DTwP-Hep B-Hib, DTwP-Hep B and hepatitis B vaccines.

The WHO team asked Panacea to put on hold shipments of the DTwP-based combination vaccines until a final decision on the acceptability for UN supply had been made by a WHO-convened adhoc committee which would be constituted to review the findings of the audit team.

UNICEF and the Pan American Health Organization, through which prequalified vaccines are supplied to developing countries, were rapidly informed of the main conclusions of the audit team.

An adhoc committee composed of WHO staff and experts from national regulatory authorities was convened to advise on potential changes to the prequalification status of the DTwP-based combination vaccines manufactured by Panacea; the continued acceptability of the oral polio vaccines produced by the company in a different site to that which was audited and supplied to countries either through United Nations agencies or by direct procurement; and the ongoing prequalification evaluation of the company's inactivated polio vaccine (IPV).

Batches of these vaccines already distributed to countries should not be recalled and should continue to be used. This is because there is no evidence of quality or safety defects with batches already distributed whereas there is a real risk, if immunization is withheld, of death or morbidity from the diseases against which the vaccines protect. The evidence includes: testing by WHO-contracted laboratories that has been performed on batches of Panacea vaccines that have been supplied through the UN system in accordance with the continuous monitoring performed by WHO on prequalified vaccines ; and review of complaints and reports of adverse events following immunization from either immunization programmes, national regulatory authorities or the manufacturer.