Effect of Storage on the Prevalent Alum‐precipitated Haemorrhagic Septicaemia Vaccine in Pakistan and Preparation of a More Efficient Oil Adjuvant Vaccine using Dense Culture of Pasteurella multocida Roberts Type 1 on an Improved Culture Medium

Abstract

Summary Significantly drastic effects of storage on the potency of the alum‐precipitated haemorrhagic septicaemia (APHS) vaccine are reported. The APHS vaccine, studied through challenge infection of vaccinated rabbits (post‐60 days of vaccination), showed 100% potency when stored at 4 °C for 30 days. The potency dropped to 20% when storage period was extended to 60 or more days. At 30 °C, the potency reduced by 40, 40 and 60%, respectively, after 30, 60 and 90 days of storage, while, at 37 °C, the decrease was 60, 60 and 100% after 30, 60 and 90 days of storage, respectively. In view of this, the oil‐adjuvant (OA) HS vaccine was developed by culturing Pasteurella multocida on a medium comprising yeast extract, sucrose, trypticase and sodium bicarbonate, under continuous aeration at 37 °C. This gave a far better bacterial count (maximum count 15 times 108/ml) than the conventional APHS vaccine (maximum count 6 times 108/ml). The OAHS vaccine‐carrying water‐in‐oil emulsion remained stable at room temperature for 1 year. The log protection values of the two batches of the OAHS vaccine, studied in mice, were 5.2 and 5.3, as against 1.9 of the APHS vaccine.

On-farm storage of livestock vaccines may be a risk to vaccine efficacy: a study of the performance of on-farm refrigerators to maintain the correct storage temperature

“…For the majority of vaccines, especially those used in cattle, sheep and pigs, the recommended storage temperature (RST) is between 2 °C and 8 °C [ 4 ]. Vaccines stored at different temperatures could result in potency loss and impaired efficacy [ 5 – 7 ]. Furthermore, emphasis is being increased nowadays on vaccine management to protect vaccines from freezing [ 8 , 9 ] as cold chain practices tend to prioritize protecting vaccine from heat damage.…”

A survey of the usage and storage practices of veterinary medicines among communal cattle farmers in the Kabbe South Constituency, Zambezi region.

“…To ensure efficacy, veterinary medicines should be protected from temperature changes, direct sunlight and moisture variations. Vaccines need to be stored at 2-8 o C (Sheikh et al, 1995;VMD, 2015) or following the manufacturer's recommendations as indicated on the medicine label (VMD, 2014). Inappropriate handling, storage and use of vaccines may result in limited, no effect or even adverse effects on human and animal health (CDC, 2015).…”