Your Guide To Vaccine Trials:
In the past month there has been growing attention to the prospects of a COVID-19 vaccine. There are many confusing aspects to the development of a vaccine and there will likely be some conflicting information out there. The goal for this letter is to try and provide you with the information and tools needed to accurately and effectively assess the information being provided to you. Today we will be focusing on the overall aspects of how a potential COVID-19 vaccine would work and how it will be developed so that you can navigate the news cycle in an informed way!
SARS-CoV-2 uses a protein spike on the surface of the virus to penetrate and enter human cells. Protecting against this mechanical intrusion at the cellular level is what will help provide us immunity from infection. According to the Johns Hopkins Center for Corona Virus, there are multiple ways in which to do this and will be briefly broken down below. (This is paraphrased from their website and has some analogous commentary in my own words):
· Inactivated Vaccines- Use “dead” virus to help expose your body and immune cells to “dummy” versions of the virus so that it can develop immunity. This is the same method for many types of the flu vaccines and has been a tried and true way to develop vaccines. Think of this as a sports team scrimmaging against the rival team in the pre-season.
· Protein-Based Vaccines- These types of vaccines use small bits of proteins from the virus, such as its protein spike in order to alert our immune cells to how a virus might present. Think of this like the “mug shot” method of catching a criminal virus. This method is used in the hepatitis B and shingles vaccines.
· Viral Vector Vaccines- Use DNA from similar or inactivated SARS-CoV-2 virus to allow human cells to identify and “map” or “copy” the viral DNA so that it can be recognized early when the patient is exposed. Think of this as searching a document for a specific word using the command “F” function like you can do in Microsoft word. This method is often used in cancer treatment research methods.
There are multiple vaccines under development from different companies using each of these methods. It is not yet clear which method will be most effective. However, the Center for Disease Control (CDC) has an established protocol for vaccine development. It includes:
· Exploratory stage
· Pre-clinical stage
· Clinical development
o Phase one: small groups receive the vaccine
o Phase II: clinical study is expanded to include a broader population with a focus on specific population
o Phase III: broad testing with thousands of people and is tested for efficacy and safety
· Regulatory review and approval
· Quality control
With Pfizer and Moderna each announcing this month that they believe their vaccine is 90-95% effective, it signals that they are both in phase III trials. At the conclusion of these trials they will face a regulatory review board which will conduct a thorough review of the biologics license application, inspection of manufacturing facility and a presentation of findings to the FDA’s products advisory committee. After approval, the FDA will continue to track and analyze side-effects and efficacy of different vaccines.
Types Of Trials And What They Mean
Moderna just released that they believe their vaccine is 94.5% effective. They released this information based on early results from a double blinded phase III study. In a double blinded study, some participants receive a placebo (a harmless substance used as a control in a study) and some participants receive the actual product (in this case the vaccine). Neither the volunteer patients nor those running the trial know who received which. This type of study is academically seen as the standard of a true scientific study. There may be “confounding factors” or additional disclosures that need to be made such as a certain number of trial participants that withdrew for some reason, or if there were conflicts of interest. The point going forward is that when learning about a new published study it is important to identify the type of study that was conducted and the possible pitfalls or upsides to that specific study. The link below provides a great breakdown of this topic and may be helpful guiding you as you analyze future reports during vaccine development:
According to the BBC, Moderna’s trial included 30,000 people with half receiving the vaccine and the other half receiving a placebo. The analysis was based on the first 95 people to be diagnosed with COVID-19 and found that only 5 of those who were diagnosed with COVID had received the vaccine and the other 90 had received the placebo. The company claims that this represents a 94.5% efficacy rate. It should be noted that this is an extremely small sample size when one considers the initial trial size of 30,000 people. Sample size is the number of participants in a study. Think of this like a representation of a population as a whole. How many people would you feel properly represent your immediate family, community, state or country?
Additionally, certain methods of statistical analysis can be used to manipulate data to fit a distribution curve and should be disclosed by those conducting the study. Statistical analysis can become quite complicated and burdensome but generally an article or published study should discuss their analysis methods and disclose any outlying data that did not fit the pattern of the rest of their findings. In summary, we don’t yet have enough information to truly assess whether this sample size is large enough to properly evaluate the efficacy of either vaccine.
Finally, the takeaway point is not to highlight or critique either prominent potential vaccine, but rather to provide a road map to the analysis of information that will be coming out in the future. Neither Moderna nor Pfizer have completed phase III trials, nor have they released a comprehensive report of their studies and this letter is not meant as an endorsement or condemnation of either potential vaccine.
Key Points in Analyzing Vaccine Information:
· How will the vaccine work (inactivated/protein-based/viral-vector)
· Type of study conducted (pitfalls/positives?)
· Sample Size (is it large enough to represent a population?)
· Disclosures (conflicts of interests, outlying data points, funding of the study)
· Efficacy (statistical analysis of the results)
If you found this helpful, please share it with friends and family members and tell them to subscribe to stay up to date on the latest developments in the search for a COVID-19 vaccine! If you have any questions or comments, please email:
Ben Velardi, Author/Founder
Where can I find more information?
Johns Hopkins Center for Carona Virus:
New England Journal of Medicine:
Study analysis methods and design: