Ensuring vaccine safety: Case studies of falsified influenza vaccines detected in Brazil.

Falsifications related to health technologies-including vaccines-are a growing threat to patient safety and health systems on a global scale and can cause serious harm to the population (especially vulnerable groups). In Brazil, the manufacturing and spread of counterfeit medicines are prevented through joint actions between different government agencies. In this study, we analyzed three cases of influenza vaccines suspected of counterfeiting. The samples were seized by officials and received by the National Institute for Quality Control in Health (INCQS), the national quality control reference laboratory of the Ministry of Health of Brazil, in 2010, 2017, and 2020. We report the results of our analytical investigations and emphasize the importance of strengthening the partnerships between various national agencies. The seized samples were visually inspected, and their information was compared with that of genuine vaccines (as recorded in the INCQS database). The specific analytical tests were based on quality control tests for biological products. Our results confirmed that all seized samples were falsified. We emphasize the importance of fostering international and intra-national collaborations between various national agencies (such as drug regulatory authorities, official laboratories, customs departments, police forces, and civil society). As demonstrated here, such collaborative actions are essential for combating the release of falsified medical products, safeguarding public health, and strengthening health systems.

Establishment and validation of an ELISA for the quantitation of HBsAg in recombinant hepatitis B vaccines.

Commercial enzyme-linked immunosorbent assay (ELISA) kits for the determination of the in vitro potency of recombinant hepatitis B vaccines, which detect hepatitis B surface antigen (HBsAg), have been used frequently as an alternative for traditional in vivo potency tests. With the constant need for validation procedures, an ELISA that could be employed to determine the in vitro potency of five recombinant hepatitis B vaccines simultaneously was established using two monoclonal antibodies. The use of two monoclonal antibodies produced "in house" specific for the small envelope protein S of the hepatitis B virus (HBV) resulted in the production of a highly specific, sensitive and stable ELISA. The standard ELISA parameters used in this study, considering the HBsAg content of each recombinant hepatitis B vaccine evaluated, resulted in a standard curve that could be applied for potency evaluations of different, commercial hepatitis B vaccine lots.