Evaluation of quality of hepatitis B vaccines circulating on the Ugandan market

Abstract

Vaccination is the greatest public health intervention in these modern times. Since the Ministry of Health -Uganda rolled out the Hepatitis B vaccination program, there has been a continuous decrease in the number of new Hepatitis B infections in Uganda. However, this can only happen when the vaccines are safe, effective and efficacious. There have been reports from the Ugandan media about ‘‘fake’’ vaccines circulating on the market. This study was aimed at evaluating the quality of the various brands of Hepatitis B vaccine circulating on theUgandan market. Five commercial brands of Hepatitis B vaccines (Euvax B, Engerix- B, Revac B, Bevac and Hepatitis B vaccine from the serum institute of India were purchased from different pharmaceutical suppliers in Uganda. Then after the purity of the different vaccine brands was evaluated by testing for the presence of free formaldehyde using a spectrophotometer, the concentration of the active antigen present in various vaccine brands was evaluated by using an indirect quantitative ELISA technique. Freedom from contamination of the different brands of the vaccine was evaluated by testing for the sterility and endotoxin levels. Here we demonstrate that 40% (2/5) of the investigated Hepatitis B vaccine (Bevac and Revac B) on the Ugandan market have endotoxin levels beyond the recommended limit but all the vaccine brands appeared sterile. Results of analysis show that all the sampled brands had the required amount of antigen required to elicit an immune response as stated by the manufacture. These results dismiss the false claims that all vaccines circulating on the Ugandan market are fake. This may restore public trust on the use of vaccines. However, more investigations should be done on the Bevac and Revac B vaccine brands that appeared to have endotoxin levels beyond the recommended levels. Hepatitis B vaccine quality testing provides confidence to the end users and this study recommends that there should be a strict analysis of all commercial vaccines before they are licensed for use in the country. This will ensure that only vaccines that meet the standard requirements are allowed on the market.