Effect of Extended Transit and Temperature Variations on EID50 Values of Thermostable NDVI-2 Vaccines

Abstract

Temperature alterations due to poor cold keeping condition have consistently posed a challenge to vaccines dose EID50 titre value. The sensitivity of Newcastle disease vaccine to temperature variations due to poor cold storage condition in rural settings, led to the development of the NDVI-2 thermostable vaccine, which is known to exhibit a thermostability of 3 hours at 56 °C. In this study, three Newcastle disease vaccines (NDVI-2) with EID50 titre per dose values of log10 EID50 7.7, 7.6 and 6.75 respectively from vaccine production facility at the National Veterinary Research Institute (NVRI), Vom Nigeria, were sent for certification at African Union laboratory at Debre Zeit, Ethiopia under cold condition; using ice packs for cold chain maintenance. Tracking of the vaccine in the course of freight to the certifying laboratory revealed changes in the original transit route by the airline and delay by custom at the receiving country port. Thus, a 12 hours transit freight was delayed for over 7 days before arrival at the certifying laboratory. Though, the EID50 titre per dose values of these vaccines were originally well above recommended EID50 5.5 per dose value by log 2.2, log 2.1 and log 1.25 for NDVI-2 respectively. Comparing these vaccines EID50 values obtained from the certifying laboratory in relation to values initially obtained by the Quality Control Division of the producing Institute (NVRI), revealed loss of EID50 titre per dose value by log101.2, and log10 0.8 among two of the certified vaccine batches; with one of the certified vaccines retaining its original EID50 titre per dose value. This result attest that NDVI-2 thermostable vaccine produced at NVRI, Vom Nigeria are robust and of high quality. Thus, the findings of this study have further demonstrated that temperature variations, prolonged vaccine transportation under poor cold chain can affect the EID50 per dose value of a wholesome, field fit vaccine irrespective of the vaccine thermostability.

Comparison of NDVI-2 Vaccine EID50 Titre Values After Three Weeks of Freight Under Cold Monitored Storage Condition

“…The re-validated vaccine final EID 50 titre per dose values were well within the acceptable EID 50 potency titre value for NDVI-2 ( 1), incooperated into these NDVI-2 vaccines batches while being compounded as observed in this study, were able to carter for the vaccine EID 50 titre loss observed (Table 2). Our finding and that of [10], is a further confirmation of the robustness, and integrity NDVI-2 vaccine, produced by the National Veterinary Research Institute Vom, Nigeria. It is thus suggested that for all vaccines, be it thermolabile or thermostable, that extra EID 50 value of about 1 to 2 EID 50 logarithm values be in-cooperated to carter for possible EID 50 titre loss that might occur due to poor cold vaccine storage conditions, especially in regions of the world with limited, or poor electricity supply.…”

“…The use of the NDVI-2 thermostable vaccine under poor cold storage conditions does not entail or encourage complete or absolute negligence of standard vaccine cold storage condition; despite the NDVI-2 vaccine thermostable nature. This is also in agreement with the findings of [10] where it was reported that the thermostable nature of the NDVI-2 vaccine does not exempt it from EID 50 titre value drop. It is therefore important to note that a thermostable vaccine must be handled with same care accorded to other thermo-sensitive biological products; thus, thermostable vaccine such as NDVI-2 cannot be expose to sunlight and frequent alterations in temperature and still be expected to remain potent [1].…”

“…Vaccination against ND has been shown to be an efficient control strategy against ND outbreak in susceptible poultry flocks [3,7,14,16]. Strategic Newcastle disease control through vaccination require the use of wholesome, safe, efficacious and potent ND vaccine [10]. Therefore, careful handling of vaccine according to the required standard method in regards to cold storage condition of vaccine after production till the time of use, is critical in effective ND vaccination control strategy, especially in Newcastle disease endemic regions.…”

“…Therefore, careful handling of vaccine according to the required standard method in regards to cold storage condition of vaccine after production till the time of use, is critical in effective ND vaccination control strategy, especially in Newcastle disease endemic regions. The strategic Newcastle disease control programme in endemic regions will involve series of vaccinations and re-vaccinations in accordance with stipulated NDVI-2 vaccination schedule [10]. Thus, vaccine cold storage and cold keeping condition during transit, till the time of use is critical for an efficient Newcastle disease eradication programme.…”