Detection of cold-adapted vaccine-strain influenza virus using two commercial assays.

This research study focuses on the detection of a cold-adapted influenza virus in horses that received an intranasal vaccine, using two commercial assays. The findings reveal that all horses tested positive with one assay during the study period, and an ongoing positive result in the other indicates possible infection among non-vaccinated horses due to the shedding of the virus by vaccinated ones.

Introduction to the Study

• The research aimed at studying the identification process of the influenza virus in animals after they were vaccinated.
• The commercial assays examined were the Flu OIA assay and the Directigen Flu A assay, which are both commonly used for antigen detection.
• The subjects of the study were ten horses, including seven vaccinated and three unvaccinated ones.

Process and Findings

• Intranasal vaccination was given to seven horses, all of which subsequently tested positive for influenza using the Flu OIA assay.
• However, with the Directigen Flu A assay, only one horse registered a positive result at one sampling period.
• Most of the horses were detected positive in the first three days following the vaccination, and several horses intermittently showed positive results over several subsequent days.
• The detection of positive results for the influenza virus in non-vaccinated horses indicates that they might have been infected by the vaccine-strain virus that was shed by the vaccinated horses.

Significance of the Study

• The research provides crucial insights into the interpretation of influenza antigen detection tests, especially under circumstances where vaccine-strain viruses are used.
• It highlights the importance of monitoring vaccinated and non-vaccinated populations post-vaccination alongside the correct interpretations of test results.
• It also points to the possible contagious effect of the vaccine-strain virus among non-vaccinated subjects.

Conclusion

• The study concludes that discrepancies exist between different commercial assays used for antigen detection post-vaccination.
• It underscores the need for care in interpretation and observation of test results, especially in times where vaccine-strain viruses are employed.
• Finally, it points out the risks associated with the shedding of vaccine-strain viruses.