Author, Year and Purpose
Jackson et al., (2010) conducted a double-blind, randomized study to evaluate the efficacy, safety, reactogenicity, and immunogenicity of a TIV (trivalent inactivated split virion influenza vaccine) against a VMCCI (vaccine-matched, culture-confirmed influenza).
Level of Experimental Design:
The level of experiment design was double level experimental study involving two general levels, one involving a placebo and the other, the real vaccine being tested.
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Sampling Measurement
The study was conducted within the USA over a two-year period between 2005 and 2007. More specifically, the study was carried out within the two respective flu seasons of 2005-2006 and 2006-2007. The total sample size was 7219 amounting to 95% of the initially targeted sample group. They were all volunteers between the ages of 18 and 49 years and all living in the USA. A larger sample had been selected in anticipation of some either failing to follow through or getting disqualified hence, the 5% did not affect the overall results of the experimental process. Among the definitive disqualifying factors was those found to be high-risk influenza patients based on Advisory Committee on Immunization Practices (ACIP) parameters, and those with a serious medical or psychological problem or for women, pregnancy. Enrolment was undertaken in 37 centers in the 2005-2006 season and in 44 centers in 2006-2007 . The sample group was then divided into two main categories of 18-34 and 35-49 years. For the purposes of variety, being in the season one trial automatically disqualified one from being in the season two trial.
Through a stratified randomization on the ratio of 1:1, the sample group got either a single 0.5 mL injection of FluLaval, a TIV trademarked to GlaxoSmithKline group of companies or a placebo. Three separate antigens and three lots of vaccines were used for each respective season.
Study Variable
The participants were divided equally into three different lots based on the three different antigens. Close monitoring, including regular telephone contact, was maintained for all participants throughout the pendency of the research. The primary endpoint was the ability of the vaccine to prevent the advent of type A and type B influenza in both respective seasons as compared with the control group who would be given a placebo. The hypothesis used for the research was based on an expected efficiency of 97.5% CI lower bound of >35% for vaccine efficacy.
Main Results and Findings
As per the final outcome, 3714 participants were in the VIT group while 3768 fell in the Placebo group. It is worthy of notice that no culture-confirmed influenza illness was among the 5% exempted group. Based on the results of the research, Influenza prevalence in the TIV group was 23/3714 which amounted to 0.6%. In the placebo group, it amounted to 45/3768 accounting for 1.2%. The rates among the placebo group were thus double that in the TIV group. The results of the study show that the use of a placebo exponentially improved immunity against influenza. However, the rate of immunity boost realized through the experiment was exponentially lower than the one that the researchers had anticipated, based on their hypothesis. Further, the researchers noted that there was an overall lower prevalence of influenza among all the participants, a fact that was also replicated in the general population within the two seasons. Nonetheless, the vaccine was still found to have a high level of accuracy. On the secondary parameters based on consistent monitoring of the participant, the vaccine was adjudged as safe as it did not create any noticeable adverse side-effects. Finally, with regard to consistency, the two seasons of testing revealed that the average reactogenicity and immunogenicity of the vaccine did exhibit consistency. At the same time, consistency was also found to transverse the three different antigen lots and the two selected age groups of 18-34 and 35-49 years.
Conclusion
Based on the totality of the research and discussion, TIV was adjudged as acceptable safety profile whose immunity benefits far exceeded any risks it may pose.
Discussion on Strength and Weakness of Article Submitted
Based on the letter of the article, it would be easy to assume that its strengths far outdo its weaknesses. The authors go out of their way to outline the many processes they underwent to ensure that the experimentation process was above board. Further, several groups and organizations were involved in the cross-checking and evaluation of the processes and procedures to augment the validity and reliability of the research. Secondly, the design of the experiment being a double-blind, randomized study with both a test group and a placebo group further augment the validity and reliability of the research. The fact that the researchers used a relatively large sample spread across the USA and over a duration of two influenza seasons is also among the strengths of the research.
When it comes to weaknesses, the primary admitted weakness in the research is that the two seasons selected by the researchers, being the 2005-2006 season and the 2006-2007 season exhibited a lower prevalence of influenza than is expected in the USA. Based on this weakness, it is not possible to tell whether the outcomes would be replicated in a relatively ordinary flu season. Another major weakness of the research study is not per se academic in nature since a specific product that is available in the market and trademarked to a major pharmaceutical marketer was not only used in the research but also indicated in the journal article. An active or passive bias towards the product cannot be ruled out, a fact that amounts to a weakness for the research. Finally, the research sample was made up of human beings in their natural habitat. Whichever steps the researchers may have undertaken to avoid secondary interference, there is no way to tell if such interferences played a role or to determine what role the interferences played.
Reference
Jackson, L. A., Gaglani, M. J., Keyserling, H. L., Balser, J., Bouveret, N., Fries, L., & Treanor, J. J. (2010). Safety, efficacy, and immunogenicity of an inactivated influenza vaccine in healthy adults: A randomized, placebo-controlled trial over two influenza seasons. BMC Infectious Diseases , 10 (1).
