Thirdly, the post-trial crossover vaccination with either bivalent HPV or hepatitis A may have been influenced by many factors and could be subject to unmeasured confounding, as women were no longer randomized.
Thirdly, the disbelief in the effectiveness of influenza vaccination in protecting themselves or patients was reported as a reason to not get vaccinated.
Thirdly, some observers argue that Islamist insurgents' animosity towards polio vaccination programmes is the logical result of Islamic theology.
Thirdly, this study could only document the willingness of people to accept vaccination against influenza A/H1N1, which may not necessarily reflect their actual behaviour.
Thirdly, the analysis excluded the programmatic costs that would be incurred in implementing a national vaccination programme.
Thirdly, the study was performed during and after the H1N1 pandemic alert, which allowed us to investigate both vaccinations.
Thirdly, the public interest.
Thirdly, the welfare state.
