Author(s): Angus Nnamdi Oli
Context: There is need for continuous monitoring and validation of pharmaceutical
products (including vaccines) in circulation in every country. Vaccines must be
maintained in cold-chain from the manufacturer to the end user. Aims: This
study aims to validate the Oral Polio vaccines sourced from the Central Coldchain
facilities and used for vaccination programmes in South-East, Nigeria.
Settings and Design: The Study was an experimental in design and performed
in laboratory. Methods and Materials: The immunogenicity test was done using
Antibody Induction Method. This involved measuring the neutralizing antibodies
in a control group (mice given Oral Polio vaccines stored at 37°C for 12 months)
and test group (mice given Oral Polio vaccines sourced from South-east States)
after 30 days using Enzyme-Linked-Immunosorbent-Assay technique. Statistical
analysis used: One-Way Analysis of Variance (ANOVA), Dunnett’s Tests of
Multiple Comparison and Bartlett’s test for equal variances were used. Results:
All the vaccines used were within their shelf-life. The Mean ± Standard Deviation
of the temperature of the vaccines at point of collection was -19.60 ± 0.56, before
storage it was -13.00 ± 3.74 and at storage facility, it was -19.80 ± 0.60. The
mean antibody titres evoked by the Oral Polio vaccines from Enugu, Ebonyi,
Imo, Anambra, Abia and then the control were 22.90, 23.18, 18.55, 17.12, 17.38
and 7.36 IU/mL respectively. One way analysis of variance shows that there is
statistical difference (P value=0.0026) in the antibodies titres produced by the
vaccine samples. The antibodies were enough to confer protection against the
target diseases. Conclusions: This study showed that the oral polio vaccines
from the central cold-chain facilities in south-eastern Nigeria were still in good condition as at the time of sample collection and were immunogenic enough
to induce protection. The cost of immunizing a child is heightened by the inbuilt
cost of maintaining alternative power supplies to the national power grid.
It is, therefore, recommended that vaccines not requiring cold-chain storage is
urgently needed in resource-limited countries to reduce the high immunization
cost brought about by cold-chain maintenance system. This will strengthen and
enhance the process of achieving and sustaining the eradication of infectious
diseases, especially polio, in developing countries.
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