28. Read the following Science Daily article: The Lancet . (2015, March 25). Pha

Question

28. Read the following Science Daily article:

The Lancet. (2015, March 25). Phase 1 trial of first Ebola vaccine based on 2014 virus strain shows vaccine is safe and provokes an immune response. ScienceDaily. Retrieved 06 December 2015 from http://www.sciencedaily.com/releases/2015/03/150325110731.htm  

Write a brief summary (one paragraph) about the study that answers the following questions:

What was the purpose of the clinical trial?

What was the overall design of the trial?

What were the independent and dependent variables?

What was the control?

What were the results of the experiments and the major importance of the findings?

Did the studies demonstrate that the vaccine prevented Ebola? Why or why not?

What is a limitation noted by the scientists?

Explanation / Answer

SOLUTION:

What was the purpose of the clinical trial?

The purpose of clinical trials was to decide if a new medication or treatment of ebola virus vaccine was safe and effective. Clinical trials are research studies that are conducted to find more effective ways to treat, prevent, or diagnose disease. They may also be done to find treatments with fewer side effects, or treatments that are easier for patients to tolerate.

What was the overall design of the trial?

In the design of the first phase trial 120 healthy adults were randomly assigned in equal numbers to receive placebo, a low dose, or high dose of the vaccine. The randomized, double-blind, placebo-controlled,

28 days after vaccination, 38 out of 40 participants in the low-dose group and all 40 of those in the high-dose group had a positive immune response to the vaccine, with participants in the high-dose group producing higher quantities of antibodies than those in the low-dose group. No specific immune response was recorded in the placebo group.

What were the independent and dependent variables?

Dependent variable:

Dependent variable is depend on independent variable.

In the low-dose group and all 40 of those in the high-dose group had a positive immune response to the vaccine and with participants in the high-dose group producing higher quantities of antibodies than those in the low-dose group.

Independent variable:

The high dose of vaccine used in the study appeared to partly circumvent pre-existing immunity to the vector, because participants in the high-dose group had a 100% response rate, with no resultant increase in adverse events.

What was the control?

Research has indicated that this type of vaccine may increase the risk of HIV acquisitionso so future trials will need to take control on it.

In the high dose group were more likely to report pain and redness at the injection site, with a smaller number reporting mild fever and vomiting. The incidence of adverse reactions was in line with findings from previous studies of other viral-vectored Ebola vaccines

What were the results of the experiments and the major importance of the findings?

Results from the first phase 1 trial of an Ebola vaccine based on the current strain of the virus .

The results suggest that the new vaccine is safe, and provokes an immune response in recipients, although further long-term testing will be needed to establish whether it can protect against the Ebola virus.

Did the studies demonstrate that the vaccine prevented Ebola? Why or why not?

The study does not show whether the level of immune response observed might ultimately be able to offer protection against Ebola virus, and previous trials of this type of vaccine have suggested that pre-existing immunity to the virus vector used to deliver the vaccine may affect its ability to protect against the virus. However, the high dose of vaccine used in the study appeared to partly circumvent pre-existing immunity to the vector, because participants in the high-dose group had a 100% response rate, with no resultant increase in adverse events.

What is a limitation noted by the scientists?

According to scientist

"On the basis of findings, we believe that the Ebola vaccine we assessed has some potential, and a significant advantage of this type of vaccine is that stable and much easier to store or transport in tropical areas with inadequate cold-chain capacity, such as Africa. However, whether this candidate vaccine could become a final vaccine for widespread use against Ebola outbreaks is still uncertain, because of the issues of HIV-1 acquisition rates and the pre-existing immunity, especially in West Africa. More evidence from clinical trials is needed about these concerns. Furthermore, these results only assess immune response up to 28 days, so we plan to assess the persistence of the specific immune response by following up the vaccine recipients of this study."

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